16 OB Baby Owners - How Many Are Left? [Archive] - Page 3

Just Say N20

12-22-2013, 08:33 AM

One thing this discussion is proving beyond a doubt, is that the Volvo 290 is exceptionally inefficient. Rooty's 16 did run 16 mph faster than mine with just about the same hp, but I would guess it had less torque than my engine. The lower unit/prop would arguably be THE only significant difference between our boats that was responsible for the speed difference.

80 mph seems to be a wall of sorts unless something significant changes. I say this because Parnell's 1979 16 also maxed out at just over 80. I would say the structural beefing up his hull received, the exceptional interior and the 65 gallon fuel tank make his boat at least 300 - 400 lbs heavier than other 16s. But he was running the same SS, and over 500 hp.

Younger was able to run mid-80s with 400-ish hp and a Blackhawk drive. That is a significant change in the amount of lower unit drag. His was mounted a little deep, so it wasn't 100% surfacing, but it was much less lower unit in the water.

And I keep coming back to Greg's mule not hitting 80. It has plenty of power, current prop technology, a high "X" dimension almost to the point of being a surface drive, AND a pad bottom. All 4 of those elements are parts of the "holy grail" for combination necessary for big speed on a V-bottom.

There must be something else going on with my drive. I think it is mounted very deep. I spent about 6 hours truing the shape of the drive last Spring. There were some significant hills and valleys on the below water surfaces. I eventually ended up with "flat" surfaces.

However, all the other Classics with enough horsepower to spin the Solas 23 over 5,000 rpms are all running 70 mph or higher. Granted those folks are all running 18's, which are commonly accepted as being about 3 mph faster than 16's if everything else is the same.

The Solas props are also known for having very low slip numbers. The slip running my 260 hp engine, and the Solas 19 at WOT was 3.896%.

The Ultra props are known to have crazy high slip numbers. With the same 260 hp engine, running an Ultra 24 at WOT, slip was 18.17%.

However, both props turned 5,000 rpms at WOT, the Solas 19 running 53.7 mph, and the Ultra 24 running 57.3 mph.

With 430 hp, and a Solas 23 turning 5,300 rpms, running 65.2 mph, the slip calculates to 9.04% with is more than DOUBLE the slip. IF the Ultra 26 behaves consistently as compared to the Ultra 24, the engine should turn at least 5,300. At the same 18% slip the theoretical top speed would be 66.3 mph.

Ghost

12-22-2013, 08:44 AM

So Bill's experience shows that the need for longer inner strakes to go fast is not true. Once you are above 60mph they are not even in the water on the early 16 Ski Sporter's.

This sounds backwards to me.

Isn't the reason for longer inner strakes (extending further AFT, not forward) so that there is a functioning inner strake when only a little bit of the boat is in the water? I thought the reason the inner strakes didn't run all the way to the transom (on many, many models) was that the inner, aft section was always IN the water at speed, not out. So they carried the strake aft until it reached the point where it was always submerged, where anything further would only create turbulence down under water.

Any evidence that the short inner strakes were fully OUT of the water on a design is just making the case for longer strakes that could knock some of the flow of water water off of the hull and decrease wetted surface, no?

mattyboy

12-22-2013, 11:06 AM

Greg

I don't care how slick the omc lower was it would still need to put out more power than the 225 merc that pushed the baby to 74 so let's say it needed to be at 325 hp that would mean the rated HP of the super strangler would need to be DOUBLED( this rating was at the crank not the prop)

and at 155 hp I bet in 65 it would have given the 165 intercepter I/O 16 fits but in no way shape or form could approach 84 mph

from

http://www.boatracingfacts.com/forums/showthread.php?14653-omc-race-v4

The above is correct, actually the first v4 race motor was the Johnson GT115/Evinrude X115 (model # GT10S) introduced in 67, then OMC spent 2 years prototyping before introducing the Stinger/SS (Model # KC13R), then a year of prototyping again before introducing the Stinger GP/Super Strangler (model KR15M).

Horsepower wasn't officially rated on any of these but the grapevine reports I had seen and heard were:

GT10S-116
KC13R-128
KR15M-155

-at the crank.

KR15M had forged cranks and pistons and added rollers to the bearings which really added durability. GTs and KCs had a lot of issues with cast cranks and heavy cast pistons with snap ring clips and ring dowels that would work their way out.

Greg Guimond

12-22-2013, 03:27 PM

Isn't the reason for longer inner strakes (extending further AFT, not forward) so that there is a functioning inner strake when only a little bit of the boat is in the water? I thought the reason the inner strakes didn't run all the way to the transom (on many, many models) was that the inner, aft section was always IN the water at speed, not out. So they carried the strake aft until it reached the point where it was always submerged, where anything further would only create turbulence down under water.

Any evidence that the short inner strakes were fully OUT of the water on a design is just making the case for longer strakes that could knock some of the flow of water water off of the hull and decrease wetted surface, no?

Inner strakes running further aft serve a turning purpose and a lift purpose. The lift is only really relevant HELPING you to gain speed. Once you are at a certain velocity (and faster) in the wacker world you are running on a small amount of keel but mostly on the lower unit and a portion of the prop.

Greg Guimond

12-22-2013, 04:19 PM

I'm at 40% possible .... :yes:

Greg Guimond

12-22-2013, 04:33 PM

Greg, I don't care how slick the omc lower was it would still need to put out more power than the 225 merc that pushed the baby to 74 so let's say it needed to be at 325 hp that would mean the rated HP of the super strangler would need to be DOUBLED( this rating was at the crank not the prop)

and at 155 hp I bet in 65 it would have given the 165 intercepter I/O 16 fits but in no way shape or form could approach 84 mph

from

http://www.boatracingfacts.com/forums/showthread.php?14653-omc-race-v4

The above is correct, actually the first v4 race motor was the Johnson GT115/Evinrude X115 (model # GT10S) introduced in 67, then OMC spent 2 years prototyping before introducing the Stinger/SS (Model # KC13R), then a year of prototyping again before introducing the Stinger GP/Super Strangler (model KR15M).

Horsepower wasn't officially rated on any of these but the grapevine reports I had seen and heard were:

GT10S-116
KC13R-128
KR15M-155

-at the crank.

KR15M had forged cranks and pistons and added rollers to the bearings which really added durability. GTs and KCs had a lot of issues with cast cranks and heavy cast pistons with snap ring clips and ring dowels that would work their way out.

Matty, you have some hefty flaws in a lot of your information above. I'm not sayin that in a bust 'em kinda way either as you have been really helpful with a ton of info and I appreciate that. I'll give some specific comments in between the lines shortly. Everyone should remember that a few pages back, longer inner strakes were a must have. That idea got blown away. Then there was the naked weight of an early 16 which now everyone agrees is a 1,000 pounds max. I'm just saying that there are a lot of pieces to making a wacker on the backer go faster.

I need a beer, I had a jolly day on the water ........ho, ho, ho

Greg Guimond

12-22-2013, 05:05 PM

Johhny Reed is still in Ft Laud, he grew up in mine and Bert's 'hood, but he never had anything to do with OMC's or Donzi's.... may have played with a Missile or two though, he attends OFF every year, brings his red Allison/2.5

Call him up and see if he knew Walin. Johnny Reed 1971 pic Miami .............. looks like it is going to hurt

Ghost

12-22-2013, 05:42 PM

Inner strakes running further aft serve a turning purpose and a lift purpose. The lift is only really relevant HELPING you to gain speed. Once you are at a certain velocity (and faster) in the wacker world you are running on a small amount of keel but mostly on the lower unit and a portion of the prop.

Your first sentence is logically incorrect in that max speed is a limit, where gains cease. Gains in speed continue until that limit is reached. You don't get to a max velocity "and faster" but rather you increase speed until the increases cease, where you have arrived at that maximum.

All due respect, further, it is definitely incorrect to claim N2O's pic proves longer inner strakes would not add speed because the inner strake is fully out of the water. If you look at the pic in post 547, it is perfectly obvious that inner strakes, if carried further aft, would deflect water away from the hull, decreasing wetted surface. If the effect of this were the usual, that would add speed.

Wetted surface is not just below the plane of the surface of the body of water, it continues up along the hull, roughly in a triangular shape, and creates drag. Bill's pic not only shows this, but plainly obvious in the pic is where water has flowed above the lake' surface, PAST where a longer inner strake would be, only to be deflected by his outer strake. Thus it is indisputably true that a longer inner strake would impact the path of that flow, knocking some water down from the hull, and decreasing his wetted surface. And in so doing, would be expected to increase both lift and speed.

While one could argue about (or better yet, TEST) the point where this effect of decreasing wetted surface reaches diminishing returns, there is no basis to claim it would act oppositely from its normal influence. Your logic about his inner strake being out of the water is thus, exactly backwards.

The point that WOULD make sense is the opposite of yours, as follows. If Bill had inner strakes that went all the way to the transom, his WOT pic would (roughly) show a point where those inner strakes could stop, forward of the transom, without any increase in wetted surface. I suspect this is the rationale for most of our boats having inner strakes that don't carry all the way aft. It's pretty standard design.

If you look at the pic again and picture what effect longer strakes would have, I think you will see this. The only thing Bill's pic proves about not needing longer inner strakes is that you can achieve 65, or whatever speed he's going, without longer inner strakes.

Again, no offense, I'm just trying to help clarify this so you properly factor it into you analysis. Give it a look and see if you don't agree.

Greg Guimond

12-22-2013, 05:51 PM

Wetted surface is not just below the plane of the surface of the body of water, it continues up along the hull, roughly in a triangular shape, and creates drag.

In a high strung outboard application I have seen numerous rigs riding on lower units and props with only a splash of keel in the water. On I/O's you may be right because of the large extra weight. To prop ride there I/O Nordic has to use a 1350 to give some perspective.

Ghost

12-22-2013, 06:13 PM

In a high strung outboard application I have seen numerous rigs riding on lower units and props with only a splash of keel in the water. On I/O's you may be right because of the large extra weight. To prop ride there I/O Nordic has to use a 1350 to give some perspective.

Which could be a point of diminishing returns for the inner strakes going aft, as I mentioned. For instance, if the triangle of wetted surface were entirely inside of inner strakes running all the way to the transom, that'd make them superfluous at wot speed. My only point is that if you are dismissing longer inner strakes based on the inner strakes being out of the water in N2o's pic, that logic is backwards. In the pic, N2O has simply exceeded the speed where his too-short inner strakes matter, but there is every reason to think longer inner strakes might increase his top speed.

If you are correct about a particular boat running with so little hull in the water that inner strakes would not be wetted, even all the way at the transom, it is still theoretically possible that those strakes might be needed to get up to the speed where they didn't matter. (A bit like a boat that couldn't get out of the hole without tabs, even though the tabs weren't needed and actually slowed it down at WOT.). But the way to prove this would be a pic that shows the boat running with such a small amount of hull wetted.

Bottom line: if you're trying to plan/design optimum WOT speed for a 16 OB, to the extent that N2O's pic tells you anything, it is suggesting longer inner strakes would probably help. (Sounds like Rootsy knew this, if I read about his thoughts correctly.). Hope this is helpful.

Greg Guimond

12-22-2013, 06:38 PM

Some of my thoughts are below .............

Greg, I don't care how slick the omc lower was it would still need to put out more power than the 225 merc that pushed the baby to 74mph

No it would not. Horsepower plays a role but not the sole role. Slicker lower units commonly achieve the same speed as a slightly more powerful OB

so let's say it needed to be at 325 hp that would mean the rated HP of the super strangler would need to be DOUBLED( this rating was at the crank not the prop)

I'm not understanding what would need to be 325hp? Once I do I can answer.

and at 155 hp I bet in 65 it would have given the 165 intercepter I/O 16 fits but in no way shape or form could approach 84 mph

Your dates are way off. First the Super Strangler on Dr. Lou's Donzi would have been a 1975, not a 1965. The Super Stranglers were introduced in very late 1971

from ..........boatracingfacts.com/forums "actually the first v4 race motor was the Johnson GT115/Evinrude X115 (model # GT10S) introduced in 67, then OMC spent 2 years prototyping before introducing the Stinger/SS (Model # KC13R), then a year of prototyping again before introducing the Stinger GP/Super Strangler (model KR15M). Horsepower wasn't officially rated on any of these but the grapevine reports I had seen and heard were:

GT10S-116 KC13R-128 KR15M-155 -at the crank.

There is a bunch of info here but a lot of it does not apply at all. The only motor being discussed on Gerry Walin's "OB 1" is a Super Strangler KR15 8 pumper. The horsepower number of 155 is low. I am in contact with two people who will give be the straight scoop on the ponies. Ron Hill knows both of them btw.

Greg Guimond

12-22-2013, 06:50 PM

A lot of good info flowing about the purported Gerry Walin "1965 16OB#1" and "1967 Experimental 16 OB #452". Two short strake, light layup, Ski Sporter 16's that evidently hauled the mail. :bighug:

Greg Guimond

12-22-2013, 08:32 PM

If you are correct about a particular boat running with so little hull in the water that inner strakes would not be wetted, even all the way at the transom, it is still theoretically possible that those strakes might be needed to get up to the speed where they didn't matter. But the way to prove this would be a pic that shows the boat running with such a small amount of hull wetted. Bottom line: if you're trying to plan/design optimum WOT speed for a 16 OB, to the extent that N2O's pic tells you anything, it is suggesting longer inner strakes would probably help. Sounds like Rootsy knew this.

Time to re-frame the strake bake for context...............

The chat about "inner lifting strake length" for a '64-'68 16 started with a worry about chine walk. The concern was that a round hull with inner lifting strakes that terminated 55" forward of the transom could not run fast because it would chine walk. That was shown to not be true early on. My blah blah blah then progressed to the thought that you needed the longer strakes that terminate 21" from the transom to go fast. You needed more "lift" and the Ski Sporter's of 1965 and 1967 had the "55s" not the "21s" so going fast would be a challenge. That was killed as Bill's picture shows that at 65 and above they are not even in the water so they play no real role on the '65 and '67 that are the subject of the thread. The '67 goes 68mph, that has been confirmed by the owner who still has the boat. Matty is writing a story on #452 and is going to get the prop make and size from the current owner. At that point it will primarily be math to validate 68mph with the V6 JohnRude. I suck at math. At 68mph, the inner strakes are out of the water and again play no role. If the Walin '65 did in fact clock 84mph (I am still at 40% probability but moving toward 50%) it did not need/use the inner strakes at all.

The strake bake is laid to rest for the '65 and '67. Now it is on to the impact, both positive and negative, of lower unit drag and of course X for these early 16's. More for me to blah, blah, rat a tat tat about :hyper:

Just Say N20

12-23-2013, 05:51 AM

I'm thinking Ghost is making a good point (I know, shocker).

Why is it generally accepted/experienced, that a classic 18 with the same drive/power, will be about 3 mph faster than a classic 16?

One does not expect a longer, heavier boat to be faster than a shorter, lighter boat if they have the same drive/power. Both have the same 24 degree, rounded keel bottom. Both have a 7' beam. The hook in the chine of the classic 16 is completely out of the water at speed, so that hull difference is irrelevant to top speed.

The ONLY difference I am aware of, besides length and weight, is the 18 has longer inner lifting strakes. With everything else being equal, the longer inner lifting strakes are the only thing that would make a longer, heavier boat faster.

mattyboy

12-23-2013, 07:14 AM

the length of the running surface of the 16 and 18 are very close to the same except for the inner strake . when designed the added length was inserted just fwd of midship so the 16 was cut in two and the length added to the area of the helm and fwd.
The 18 to me IMO is a more symmetrical and balanced boat over the L seating 16.

mattyboy

12-23-2013, 07:25 AM

Greg

the info I posted is from guys who raced the v4

My point on HP we know 400 hp plus hp and an I/O slick shorty will see 80 mph

we know OB 200 hp and a jackplate will see 68 without strake and a 225 will see 74 with added strake

so are you saying just a slick lower is solely responsible for Lou's 16 mph gain, and that the SS OB was putting out more power than a newer 2oo hp ob if so how much more than the estimated 155 hp stated from the guys who raced them.

back to props for a second I bet Bill will see some chine walk at some point when he goes to the ultra, props on a 16 can really rock that round bottom.

Ghost

12-23-2013, 08:34 AM

Inner strakes running further aft serve a turning purpose and a lift purpose. The lift is only really relevant HELPING you to gain speed. Once you are at a certain velocity (and faster) in the wacker world you are running on a small amount of keel but mostly on the lower unit and a portion of the prop.

In a high strung outboard application I have seen numerous rigs riding on lower units and props with only a splash of keel in the water. On I/O's you may be right because of the large extra weight. To prop ride there I/O Nordic has to use a 1350 to give some perspective.

Time to re-frame the strake bake for context...............

The chat about "inner lifting strake length" for a '64-'68 16 started with a worry about chine walk. The concern was that a round hull with inner lifting strakes that terminated 55" forward of the transom could not run fast because it would chine walk. That was shown to not be true early on. My blah blah blah then progressed to the thought that you needed the longer strakes that terminate 21" from the transom to go fast. You needed more "lift" and the Ski Sporter's of 1965 and 1967 had the "55s" not the "21s" so going fast would be a challenge. That was killed as Bill's picture shows that at 65 and above they are not even in the water so they play no real role on the '65 and '67 that are the subject of the thread. The '67 goes 68mph, that has been confirmed by the owner who still has the boat. Matty is writing a story on #452 and is going to get the prop make and size from the current owner. At that point it will primarily be math to validate 68mph with the V6 JohnRude. I suck at math. At 68mph, the inner strakes are out of the water and again play no role. If the Walin '65 did in fact clock 84mph (I am still at 40% probability but moving toward 50%) it did not need/use the inner strakes at all.

The strake bake is laid to rest for the '65 and '67. Now it is on to the impact, both positive and negative, of lower unit drag and of course X for these early 16's. More for me to blah, blah, rat a tat tat about :hyper:

As I noted, N2O's pic shows you can go 65 without the longer inner strakes, if, as Woobs pointed out quite eloquently, you push hard enough. Context or no, several of your posts suggest the strakes are irrelevant and thus would not increase top speed based on N2O's pic. This logic was and remains 180 degrees from correct. The pic shows that the longer strakes WOULD be in play at 65mph, for his boat and probably for boats that were lighter and going faster. If one examines the geometry of the triangle of wetted surface, long enough inner strakes would likely be in play at virtually any speed imaginable.

As for context, there's no reason to use the broken logic cited above as part of a subjective probability estimate about whether a 16 with an outboard ever went 84 mph. In so doing, there is also the error of equating 65, 68 and 84 mph under the in-this-context-uselessly-vague heading of 'fast.' 65 is less than 68 is MUCH less than 84. As such, N2O's pic simply should not enter into your subjective probability estimate about 84. Except perhaps, in the way Woobs outlined, that from a power perspective, it seems doubtful with only 155ish HP.

Don't get me wrong. I understand the analysis that says the shorter inner strakes aren't doing anything at 65, even on a heavier 16 than an outboard. I agree with that. I'm only pointing out that this, while interesting, should have no bearing on your train of logic about the likelihood that someone reached 84 with a super Strangler.

FWIW, hope this helps.

Ghost

12-23-2013, 09:24 AM

Why is it generally accepted/experienced, that a classic 18 with the same drive/power, will be about 3 mph faster than a classic 16?

One does not expect a longer, heavier boat to be faster than a shorter, lighter boat if they have the same drive/power. Both have the same 24 degree, rounded keel bottom. Both have a 7' beam. The hook in the chine of the classic 16 is completely out of the water at speed, so that hull difference is irrelevant to top speed.

The ONLY difference I am aware of, besides length and weight, is the 18 has longer inner lifting strakes. With everything else being equal, the longer inner lifting strakes are the only thing that would make a longer, heavier boat faster.

This is a really interesting point--never thought about it that way. Now I want to lengthen the strakes on yours to see what happens...

Just Say N20

12-23-2013, 09:28 AM

Now I want to lengthen the strakes on yours to see what happens...

Where should I deliver the boat, so you can do this? :biggrin.:

duckhunter

12-23-2013, 10:18 AM

Holy smokes, it must be the beginning of winter and everyone is experiencing boating withdrawal. Interesting discussion though.

FWIW, I don't think a 16OB is breaking 80 without a perfectly rigged and propped 250+ unless it's behind a truck on the Interstate. I've messed around with bass boats with way more efficient hulls (probably heavier though) that struggled to break 80 with a 225 & a 10" jackplate. No worries about lifting strakes there either, just that 8" wide pad.

Not surprising that the 18 is faster given similar power; some hulls are exceptional like that. The 15 Whaler is significantly better-performing than the 13 Whaler, mostly due to the hook built-in to the 13s bottom. Guys have worked the hook out of the 13 with mediocre results. It's faster, but a handful to drive compared to the 15. The 15 just works, kinda like the 18.

Anyway, you guys get back to the hydrodynamic theory discussion - it's good reading. :drinkbeer:

Greg Guimond

12-23-2013, 10:24 AM

Two words for all you Dr Lou doubters and weedeater lurkers lol ........ "Parasitic Drag" :wink: I am now at 50% probability on 84mph. Will post some new info soon.

Ghost

12-23-2013, 11:29 AM

I'm going to say there's no way a 155 hp outboard pushed a real Donzi 16 to 84 mph. No way. Not 155 hp. Not possible. If an outboard 16 did 84, it did so with considerably more hp. Putting my subjective probability estimate at 95%. :)

mattyboy

12-23-2013, 12:45 PM

woobs

12-23-2013, 12:50 PM

Much of this discussion has been made comparing apples to oranges and "adjusting" with an estimate. I understand this as these are the only data points we have. good for discussion and bench racing...not great science.

So, just fer chits & giggles lets just go back here and really understand the assumptions.

1) the boat is 1000 lbs
2) the Ski Sporter is as efficient a hull as the baby (it's not but, let's live a little)
3) the strangler lower end is slick ( add 3mph)
4) a 225 hp Merc wacker will give you 74mph - benchmark
5) the Super Strangler is not 155 hp (lets generously say its 225hp)
6) 1975 prop technology is equal/better than current 2013 prop technology (While we're assuming let's not be stingey, right)
7) 10hp buys 2mph (of course there's diminishing returns but hey, it's Christmas)

So, given the above, a Ski Sporter with a 225hp Super Strangler with a low drag bottom end can meet the 74mph +3mph (77mph). This is in a perfect "planets aligning" situation. We are still 7mph short which should cost 35hp.

Is it reasonable to assume the Super Strangler puts out 260hp? (It would most likley need more than 260... again because of diminishing returns but, so what)

As optimistic as we can be and with the benefit of every doubt we still cannot hit the mark.

Is it reasonable to assume that an early version GPS was not as accurate as the current version? Early GPS used 4-5 satellites and slower cycle rates. Consumer hardware was also not near as precise as current units. I've heard the error range was 2-4mph. also other factors could affect early GPS readings. Currently, 7 to 10 satellites are the norm with high cycle precise insturments (even the $150..00 variety) and still a 0.5mph error is claimed.

Is it reasonable to assume that not ALL of the above assumptions will fall on the generous side of the comparison? I think it is wishful thinking at best that shows this boat travels at 84mph. Pick your cross... Probability .01% imho.

woobs

12-23-2013, 01:33 PM

Can anyone post a picture of a "modern lower foot" and a "vintage" one. I'd like to see the differences...
Thanks,
S.

duckhunter

12-23-2013, 01:54 PM

Here's an interesting nosecone chart from Bob's. Not sure any of these would be considered "vintage."

http://www.bobsmachine.com/images/Nose%20cone%20models.jpg

duckhunter

12-23-2013, 01:58 PM

This might do it...

http://forum.gon.com/attachment.php?attachmentid=157676&stc=1&d=1215048895

Ghost

12-23-2013, 02:09 PM

Just Say N20

12-23-2013, 02:40 PM

The picture Ghost linked was too cool not to share. Even if it was on a Mercury, rather than a Johnrude.

Greg Guimond

12-23-2013, 05:35 PM

Don't get me wrong. I understand the analysis that says the shorter inner strakes aren't doing anything at 65, even on a heavier 16 than an outboard. I agree with that. I'm only pointing out that this, while interesting, should have no bearing on your train of logic about the likelihood that someone reached 84 with a super Strangler.

Correct. As I have said, they (55s) have no bearing at 65mph, no bearing at 68mph, and would have no bearing at 84mph either which I now think is a 50% possibility. The logical train of thought is they play no role in this specific conversation regarding '64-'68 hulls powered by wackers. I was candidly shocked given Bill's I/O 16 boat is so much heavier that even in THAT instance they played no role. Very telling.

Ed Donnelly

12-23-2013, 05:39 PM

Is it reasonable to assume that an early version GPS was not as accurate as the current version? Early GPS used 4-5 satellites and slower cycle rates. Consumer hardware was also not near as precise as current units. I've heard the error range was 2-4mph. also other factors could affect early GPS readings. Currently, 7 to 10 satellites are the norm with high cycle precise insturments (even the $150..00 variety) and still a 0.5mph error is claimed.

It was not available to the public even in 1983
and didn't lose the MPH discrepency until 2000 ...Ed

Greg Guimond

12-23-2013, 05:42 PM

Greg Guimond

12-23-2013, 05:51 PM

Ghost

12-23-2013, 06:01 PM

155 is not accurate. That said, I feel you coming over to the dark side with 95% :beer:

Greg, you were right. (You suck at math.) :)

Greg Guimond

12-23-2013, 06:02 PM

I adjusted your assumptions below in red woobs ..........

Much of this discussion has been made comparing apples to oranges and "adjusting" with an estimate. I understand this as these are the only data points we have. So, just fer chits & giggles lets just go back here and really understand the assumptions.

1) the boat is 1000 lbs
2) the Ski Sporter is as efficient a hull as the baby (it's not but, let's live a little)
3) the strangler lower end is slick ( add 3mph)
Only add 3mph? Not even close to accurate. When you change car motor AQ's you pick up 5-7mph on the identical rig. I was conservative using +5
4) a 225 hp Merc wacker will give you 74mph - benchmark
The 225hp Mercury clocked a best GPS speed of 77mph, not 74.
5) the Super Strangler is not 155 hp (lets generously say its 225hp)
6) 1975 prop technology is equal/better than current 2013 prop technology (While we're assuming let's not be stingey, right)
These guys developed, raced and won multiple world records. I have a hard time thinking that they were disadvantaged in the prop area versus 2013.
7) 10hp buys 2mph (of course there's diminishing returns but hey, it's Christmas)

So, given the above, a Ski Sporter with a 225hp Super Strangler with a low drag bottom end can meet the 74mph +3mph (77mph). This is in a perfect "planets aligning" situation. We are still 7mph short which should cost 35hp.

Ghost

12-23-2013, 06:26 PM

I agree the lower is worth more than 3 mph. I could see 7.

There's no way the prop technology was better than what is available today. Best it could be is as good as the best today.

The folks who cite dyno tests on the Super Strangler say 180. Do we have reason to think it was modified and thus anywhere close to 225? Otherwise, back out 9 mph in the "math." :)

Netting out to 14 short of 84, adjusting the numbers in the prior post.

Greg Guimond

12-23-2013, 06:30 PM

Just a data point: a little digging on the web suggests the Super Strangler was about 180 hp at the crank.

i think there have been some pretty sleek lowers:

http://johnsoldmercurysite.com/phpBB3/download/file.php?id=694&sid=489f45876f77a14561d4d9730c519a8f&mode=view

Now you are starting to get to the "real stuff". I don't want to post my findings on this stuff until I speak with Bill Gohr tomorrow hopefully.

woobs

12-23-2013, 06:37 PM

Greg, you are a moving target sometimes....

4. A "new style" 1970-1978 OB 16 Baby (with the longer inner strakes) with a 2004 Mercury 225 making 225hp at 5400rpm does a video validated 74mph under perfect conditions with no trim tabs --

Also, we are looking at the performance of the 225 Merc. o/b... not an AQ "car motor" so 3mph is very reasonable.

...and prop technology hasn't improved in almost 40 years??? Really? They kept the secret that long?

I understand you have faith in your convictions however you really can't just pick and choose what supports your theory and disregard the rest. You are stretching... and even with concessions on every point it still does not add up.

I don't need to change your mind in fact, sometimes conviction like yours leads to great discovery. But, I'm an ol' fuddy duddy and although I'm Canadian, maybe I should be from MISSOURI. ( A dyno sheet on the Strangler would be a nice piece of info.)

I firmly believe that after all this discussion the power of that motor will tell the tale.

Greg Guimond

12-23-2013, 06:40 PM

Greg, you were right.

All in good fun! I'm more interested in getting to the truth one way or the other. I'm still at 50% on 84mph. That makes me Switzerland

Ghost

12-23-2013, 06:46 PM

There's an old joke about how many social-workers it takes to change a lightbulb. ("Only one, but the lightbulb has to want to change.")

But even in the joke, the wanting isn't enough on its own. :)

Greg Guimond

12-23-2013, 06:55 PM

Greg, you are a moving target sometimes....

Also, we are looking at the performance of the 225 Merc. o/b... not an AQ "car motor" so 3mph is very reasonable if not generous.

...and prop technology hasn't improved in almost 40 years??? Really? They kept the secret that long?

I understand you have faith in your convictions however you really can't just pick and choose what supports your theory and disregard the rest. You are stretching... and even with concessions on every point it still does not add up.

I don't need to change your mind in fact, sometimes conviction like yours leads to great discovery. But, I'm an ol' fuddy duddy and although I'm Canadian, maybe I should be from MISSOURI. ( A dyno sheet on the Strangler would be a nice piece of info.)

I firmly believe that after all this discussion the power of that motor will tell the tale.

woobs not trying to be a smart arse here so let me go through it for you as you are missing things again. I used the 74mph # because it was shown on youtube and a lot of folks would have been skeptical even with that. The BEST top # was 77mph with multiple runs at 76 for that boat. I wanted to use 74 to be conservative just like I decided to use +5 on the AQ's when most would say +6 or +7. On the car motor versus O/B 3 mph comment I actually don't follow that particular statement. On prop technology, you are correct that FOR THE MASSES the technology has made incredible improvements. On a race motor? Not so much. These guys were some of the best and brightest in the world for both Merc and OMC, they knew what worked and what did not for top end so I view it as neutral like Ghost.

I'm 50% as I said on 84mph. I have equal faith one way or the other. Only interested in the facts. And in keeping the banter line on full winter tilt.

What's the thingy with the car motor versus O/B you said/meant?

mattyboy

12-23-2013, 07:12 PM

Matty, there is NOTHING modern about the gear case on #452, nothing. In addition modern or old is irrelevant in this particular conversation. It is about three things, parasitic drag, horsepower, and WOT RPM, in that order. The gas tank location would not even matter as I have never attempted to post a big # with more than a 1/8 to 1/4 tank of fuel and those tanks a small so they don't weigh much empty. You boys would no how much an empty tank weighs.

ok so weight has nothing to do with it especially where it is or isn't ?????? then why do you have so many posts about weight in this thread

again your speed runs mean didley **** your boat is totally different bottom and all

the statement i made holds true hull 452 is the closest example to Lou's boat not yours not bill's not rootsy not a 16 classic outboard. a left handed helm lounge seat short strake OB 16. so again I ask where does the 16 mph increase come from

Fonzi just drank the cool aid and is lined up with the ramp

woobs

12-23-2013, 07:27 PM

Greg, I'm not trying to be a Mr. Smarty pants either. And, I don't think I'm missing too much. I have no stake in confirming or disproving any claim. I joined the conversation because I was interested in the subject and, your early arguments were all over the map comparing things with no base while combining conclusions. This hasn't really changed.

I didn't see the you tube. So, I can only go by what is posted. You posted 74. When it doesn't fit now it's 77. The Strangler was 155hp. That didn't fit so now it's more (okay, how much more). I'm not used to facts being so variable.

The 74 was recorded with th Merc... Not an AQ.

The difference between an AQ lower and a Strangler lower may be 5-7 mph.
The difference between an AQ lower and the the Merc lower... who knows but I bet the Merc is 3-5 better because the AQ in known to be inefficient.
The difference between the Merc and a Strangler...probably less than the 5-7 claimed from the inital comparison with the AQ. 3-4 sounds reasonable to me. Taking the largest delta and applying it to the closest competitor (which is different) is apples and oranges again.

I don't for a second believe that someone in 1975 had a prop that performed so well and it stayed a secret for all this time. Racing secrets are the most fleeting of all. I raced semi-pro cars fot 15 years... even in F1 secrets last but a few weeks. The intelligence and experience of the people that designed and made the prop is also moot as there are bright people in every industry... and this is a competitive industry. And whoever designed that prop (if that good) probably didn't retire just then. If they had that knowledge they'd be makin' props till the money ran out. At the cost of props today they're probably still makin' 'em.

It's a good conversation. Interesting to consider the factors needed for each occurance. But it's hard to jump between conclusions drawn from comparisons that are not like comparisons as each time there is a "fudge factor". Do it twice in one argument and we may as well be talking about ping pong balls vs. basketballs.

Greg Guimond

12-23-2013, 07:28 PM

More data fine Sir ...........

ok so weight has nothing to do with it especially where it is or isn't ?????? then why do you have so many posts about weight in this thread
I never said weight means nothing. I said that in the #452 situation and in the Gerry Walin '65 situation the gas tank placement would not mean much at all. It would have been run low on gas tank for top speeds Doc Lou knew. Now what a gas tank actually weighs empty I don't know. Is it 100lbs Matty? Do you know?

again your speed runs mean didley **** your boat is totally different bottom and all
I have not brought my boat into this thread although others have, not sure where you are coming from on this one.

the statement i made holds true hull 452 is the closest example to Lou's boat not yours not bill's not rootsy not a 16 classic outboard. a left handed helm lounge seat short strake OB 16. so again I ask where does the 16 mph increase come from
I agree that #452 is the closest to compare. We are getting to where the 16mph came from potentially but I am still at 50%. What I was saying is that the lower unit on #452 is in no way better than that of a Super Strangler's gearcase. Zero, nada, no way. Those cases are slow, thus a slow case went 68mph. I'm happy to bring you threw the specifics.

Fonzi just drank the cool aid and is lined up with the ramp
What you talkin about Willis lol

Greg Guimond

12-23-2013, 07:43 PM

More data for you woobs ............

Greg, I'm not trying to be a Mr. Smarty pants either. And, I don't think I'm missing too much. I have no stake in confirming or disproving any claim. I joined the conversation because I was interested in the subject and, your early arguments were all over the map comparing things with no base while combining conclusions. This hasn't really changed.
I have no stake either so we agree on that. I am 50% on 84mph.

I didn't see the you tube.
You should watch it. It's pretty cool.

So, I can only go by what is posted. You posted 74. When it doesn't fit now it's 77.
I'm still using 74mph, I'm just educating you that 74 is conservative (although I'm still using it) as that boat went 77. In other words you should take great comfort in 74 but when you build up your analysis you should attach a little thought to 76 & 77 as you accrue the mph "gap". How about you use an additional +1mph?

The Strangler was 155hp. That didn't fit so now it's more (okay, how much more). I'm not used to facts being so variable.
You should read the entire thread. Not once did I say 155hp. I said many times that I was trying to get the real prop horsepower. Matty said 155, not me, ever.

The 74 was recorded with the Merc... Not an AQ.
Yes, I know that, I was the person who first researched it and then posted it.

The difference between an AQ lower and a Strangler lower may be 5-7 mph.
You are jumping WAY ahead. No one yet knows what the drag difference is between the two. Btw, a Strangler is an entirely different motor from a race Super Strangler KR15. I'm not used to motor facts being so variable.

The difference between an AQ lower and the the Merc lower... who knows but I bet the Merc is 3-5 better because the AQ in known to be inefficient.
Which AQ Lower? I can't even attempt to answer the remainder of your statements below until I know this.

The difference between the Merc and a Strangler...probably less than the 5-7 claimed from the inital comparison with the AQ. 3-4 sounds reasonable to me. Taking the largest delta and applying it to the closest competitor (which is different) is apples and oranges again.

I don't for a second believe that someone in 1975 had a prop that performed so well and it stayed a secret for all this time. Racing secrets are the most fleeting of all. I raced semi-pro cars fot 15 years... even in F1 secrets last but a few weeks. The intelligence and experience of the people that designed and made the prop is also moot as there are bright people in every industry... and this is a competitive industry.

woobs

12-23-2013, 08:23 PM

Greg really, 1 mph...74 is what you posted ...okay 74 (+/-1). :)

I read ALL the posts in this thread...twice. (And many more than that cause I'm not that smart :) ). I stand corrected as in post #324 you posted a value for the SUPER strangler quoting JWTjr at 150-165hp (conservative would say 157-158 hp). in Post #326 you speculated a further 10% due to exhaust and in post # 341 you claimed 177 hp for the SUPER Strangler. After taking the max values and bumping it 12hp we have still assumed more as it doesn't fit your theory.

I must apologise for use of the name Strangler as we have ONLY really been talking about the SUPER Strangler in context and I didn't type it, believing to be on the same page as the conversation and a lazy typist. please don't let this distract from the point. You can assume I meant SUPER Strangler.

"I decided to use +5 on the AQ's when most would say +6 or +7" AGAIN, this is YOUR estimate. I didn't jump ahead. I followed your comparitive assesment. And this time you are right... Nobody knows. As to which AQ lower, it must be the one we were talking about at the time you made the statement... Bills perhaps? Early to late? The difference here does not correlate to a difference between the Merc and the Super Strangler but, you made that comparison. Apples and Oranges.

C'mon Greg, are you trying to lose me in the details???

Greg Guimond

12-23-2013, 09:09 PM

Some more info for you woobs .........thx

Greg really, 1 mph...74 is what you posted ...okay 74 (+/-1). :)
In this thread each mph obviously counts. Does this mean you agree to use 75mph for the Merc 225?

I read ALL the posts in this thread...twice. (And many more than that cause I'm not that smart :) ). I stand corrected as in post #324 you posted a value for the SUPER strangler quoting JWTjr at 150-165hp (conservative would say 157-158 hp). in Post #326 you speculated a further 10% due to exhaust and in post # 341 you claimed 177 hp for the SUPER Strangler. After taking the max values and bumping it 12hp we have still assumed more as it doesn't fit your theory.
Thank you for standing corrected given they were JWTjr's #s. I am in contact with Bill Gohr next. Now as to the stacker exhaust I did speculate 10% possible improvement which would equal between 165hp and 182hp total BUT the actual prop shaft horsepower that JWTjr claims for the race Super Strangler is yet to be confirmed by a second (and hopefully third) source. Thus, it fits my theory perfectly. Gain data from more than one source.

I must apologise for use of the name Strangler as we have ONLY really been talking about the SUPER Strangler in context and I didn't type it, believing to be on the same page as the conversation and a lazy typist. please don't let this distract from the point. You can assume I meant SUPER Strangler.
Super :smile:

"I decided to use +5 on the AQ's when most would say +6 or +7" AGAIN, this is YOUR estimate.
Wrong, this +5 is fact. The +6 to +7 is an estimate by others. The +5 has been provided by and verified by many, many people on this forum. The +5, (again conservative) is absolutely unchallenged. Ask Matty, BUIZILLA, and Ed D for starters.

I didn't jump ahead. I followed your comparitive assesment. And this time you are right... Nobody knows. As to which AQ lower, it must be the one we were talking about at the time you made the statement... Bills perhaps? Early to late? The difference here does not correlate to a difference between the Merc and the Super Strangler but, you made that comparison. Apples and Oranges.
I still can't quite understand your sequence here so let me say this. A lower unit is a lower unit. They each have an X dimension and the actual gearcase shape has certain parasitic drag tendencies. Whether a lower unit is attached to an O/B or an I/O it still has drag. Drag slows down boats. This is apples to apples unless I am missing something? The reason you jumped ahead was that nothing has been researched on the Super Strangler gear case option........yet. This is why I am at 50%.

C'mon Greg, are you trying to lose me in the details???
No, not at all. I'm not that bright.

woobs

12-23-2013, 09:34 PM

When you quote a number even with a different source you must own it. You quoted JWTjr.

Regardless where the AQ estimate originated, you used it (at 5mph) in refrence to a benefit the Super Strangler enjoys over other drives due to its lower drag. This is your comparitive estimate.

Just because the difference between AQ lowers is that much, it in no way relates to the slippery Super Strangler in any comparison. Non quantitatively we can estimate the Super Strangler is better than the AQ. We can estimate that the Merc is better than the AQ. We could even estimate that the Super Strangler is better than the Merc but, by a smaller margin than it's triumph over the AQ. But we still can't say the Super Strangler is worth 5mph more than the Merc.

I have not jumped ahead as it was you that claimed the slippery Super Strangler was worth a 5mph gain and justified it with a comparison of two completely different drives.

While we discuss +5-7 mph the case buys (or not) and the +1 mph of the Merc 225 details.... I believe , as I've said previously, that's mostly moot unless the power output of the SUPER STRANGLER exceeds 225hp. (48hp more than the max estimate including the 12hp we already bumped it = 60hp total increase minimum)

Greg Guimond

12-23-2013, 09:49 PM

Some more answers woobs ...........

Just because the difference between AQ lowers is that much, it in no way relates to the slippery Super Strangler in any comparison. But we still can't say the Super Strangler is worth 5mph more than the Merc.
I never said it was worth a guaranteed 5mph more than the Merc. I don't enough specific data yet. I do think it is faster though. With respect to the relation of the Super Strangler gear case to the E drive I believe that there is an absolute relational comparison, so we agree to disagree on that point.

While we discuss +5-7 mph the case buys (or not) and the +1 mph of the Merc 225 details
Are you agreeing to 75mph?

I believe, as I've said previously, that's mostly moot unless the power output of the SUPER STRANGLER exceeds 225hp.
I completely disagree. The lower unit is as or more important than the horsepower in O/B's. Let me ask you this. Why can I go 79mph with a Sporty and only 72-73 with a Torquemaster in my 16? What are your thoughts on that?

Ghost

12-23-2013, 09:58 PM

Greg, now you're double-counting. You already put in an estimate for the lower being slicker, increasing the speed at equivalent hp. You can't have it drop the hp requirement too. Rules is rules, even in La-La-land. :)

Greg Guimond

12-23-2013, 10:09 PM

Have we even arrived at what horsepower requirement the slicker lower unit requires to possibly get to 84? Not really sure where the "double" counting is occurring? Did I miss one of your posts?

Greg Guimond

12-23-2013, 10:12 PM

In theory Ghost, what horsepower would YOU think the Super Strangler would need to make to get to 84 given we do not yet know the hydrodynamics of the Super Strangler lower unit. Hazard a guess on that? I'd be interested ;)

woobs

12-23-2013, 10:14 PM

Ooooh. Purple, Must be getting ntime for more wine.

Some more answers woobs ...........

While we discuss +5-7 mph the case buys (or not) and the +1 mph of the Merc 225 details
Are you agreeing to 75mph?73-74-75 statistically within the margin of error, sure..it just shouldn't grow any more.

I believe, as I've said previously, that's mostly moot unless the power output of the SUPER STRANGLER exceeds 225hp.
I completely disagree. The lower unit is as or more important than the horsepower in O/B's. I don't think you can say the difference in drag can make up for 60hp without some data...I would venture to estimate the difference in drag would have to be huge to make up for a deficit of 60hp of drive. Plus you have already estimated 5mph for this advantage... are you counting it twice?

Let me ask you this. Why can I go 79mph with a Sporty and only 72-73 with a Torquemaster in my 16? What are your thoughts on that? I have no information to venture any analysis. And, why clutter the discussion with another comparison that has no bearing? I could guess a nose cone?

Greg Guimond

12-23-2013, 10:19 PM

woobs there is NO margin for error. I still have not heard you agree to 75 :smile: Are you, or are you not agreeing to 75mph for the Merc 225?

duckhunter

12-23-2013, 10:25 PM

Have we even arrived at what horsepower requirement the slicker lower unit requires to possibly get to 84?

What's the over/under?

I'm at 300 to do it at-will on any given day, and like Buiz said, with a weedwhacker that will turn way up.

275 to do it with all of the stars in alignment, light on gas, half a pack of smokes, and wearing sunglasses. Running downhill in a light chop in the Niagara River next to the Testarossa.

Greg Guimond

12-23-2013, 10:25 PM

If the quote thingy is no longer working that will make things go slooower for this blah blah blah session :D

Ghost

12-23-2013, 10:26 PM

Have we even arrived at what horsepower requirement the slicker lower unit requires to possibly get to 84? Not really sure where the "double" counting is occurring? Did I miss one of your posts?

Baked into your math was a 5 to 7 mph delta for the Strangler being more hydrodynamic. A delta like that is saying "other things being equal (including hp), the Strangler will be 5 to 7 mph faster." Piling on top of that an allowance for less hp based on the lesser drag is double-counting the effect of the presumably more efficient lower.

One or the other, not both.

Greg Guimond

12-23-2013, 10:29 PM

I'm at 300hp to do 84mph at-will on any given day

I like it duckie, a man with a stand. 300hp wacker = 84mph at will for the Gerry Walin 1965 short straked 16

Greg Guimond

12-23-2013, 10:30 PM

Baked into your math was a 5 to 7 mph delta for the Strangler being more hydrodynamic. A delta like that is saying "other things being equal (including hp), the Strangler will be 5 to 7 mph faster." Piling on top of that an allowance for less hp based on the lesser drag is double-counting the effect of the presumably more efficient lower.

One or the other, not both.

So I ask again, what wacker horsepower do YOU think would be required to get 84mph in 1996?

Ghost

12-23-2013, 11:08 PM

So I ask again, what wacker horsepower do YOU think would be required to get 84mph in 1996?

280 to 330.

So, a third time, you do see how you are double-counting the effect of a (presumably) slicker lower, yes?

mattyboy

12-24-2013, 08:14 AM

okay so let's see if we are going to use the 13 x 7 = 28 method of reasoning here

okay so a baby can do 75 with a 225 merc then with 200 a skisporter ob can do 68 that's 7 mph then a skisporter with 300 hp can do 84 then a baby with 300 can do 91

yup Lou is gold

easy peasy lemon squeezy

http://www.youtube.com/watch?v=XnICFjDn97o

Greg Guimond

12-24-2013, 08:19 AM

While this thread as gotten some great info out. Sometime it is a bit all over the place. Without any kind of verification dr Lou's 16 OB is very questionable We have to to speculate and verify with existing knowledge of current 16s but the setups vary to much. So lets take the closest known match which would be hull 452 experimental OB hull. It has the same bottom same basic overall weight with one exception the fuel tank weight is shifted to the back. With a raised X and a modern lower foot and 200 hp can hit 68. What can be reasonably credited for the 16 mph difference? Lou's boat would be at a weight placement disadvantage as the tank was up front leading to wetted surface. So is it just drag or can the 1971 rude SS put out more hp than a modern 1998 200 rude?

Twas the night before Xmas and Matty makes some good points Abbott and Costello aside lol. I agree that #452 is the best to use for a "baseline" comparison. So let's take a look ...........

1. You have to decide if Dr. Lou Benz was lying about his owning Gerry Walin's 1965 "OB#1" and his run of 84mph on GPS in 1996. That's an individual decision

2. #452 does have the same bottom design (with 55's) and the same weight (1000#), agreed.
3. I don't think the placement of the fuel tank means much at all. But to be thorough, how much did the early tanks weigh? We don't know that. Matty?
4. The X of the 1998 Johnson V6 175 (hopped up to 205hp) is higher, but not by much. Do we know where the current owner runs the jack plate? No, we don't. Matty?
5. The lower unit on the Johnson on #452 is not modern hydrodynamically speaking. It may be newer, but newer does not mean better in this discussion. An example is E drive vs AQ290. E drive is older but better.
6. The Super Strangler is a 1975. The horsepower of the Super Strangler has not yet been 100% verified. I'll be getting some additional data.
7. Do we know the WOT RPM of the 1998 Johnson on #452? The WOT RPM on the Super Strangler is 7200rpm
8. Do we know the size and style of prop that the current owner of #452 is running to get to 68mph? This will become very telling. Matty?
9. Do we know what steering system is being used on #452's O/B?

16mph is a ton of extra speed but there are a lot of questions above that still need to be answered. I'm still at 50% that 84mph was possible with a race motor.

Just Say N20

12-24-2013, 09:08 AM

I still don't see it. I know Ed commented that they thought he wasn't telling the truth when he got his 16 running 100. But, he did it with a boat that started life as a 16, but with the bottom mods (pad, notched transom, etc.), an e-drive and a jillion horsepower Gale Banks twin turbo engine, it was about as far from a Donzi 16 as it could be, and still be recognized as a Ski-Sporter.

And speed gains have more of a logarithmic growth curve relative to hp. If 10 hp more = 1 mph more to move from 57 mph to 58 mph, then using this formula, the additional 170+ hp I added to my boat, should have netted me 17 more mph. It didn't. It gave me about 8 more mph.

Maybe the first 1 mph gain required 10 hp, the second 1 mph gain required 15 hp (25 total), the third 1 mph gain required 20 hp (45 total), the forth 1 mph gain required an additional 25 hp (70 total), the fifth 1 mph gain required an additional 30 hp (100 hp total), the sixth 1 mph gain required and additional 35 hp (135 total), the seventh 1 mph gain required 40 additional hp (175 total additional hp), and then I got a bonus 1 mph for trying so hard. :)

Don't get all side tracked because I am using a car engine example. Especially in a short boat, the huge weight difference between a V8 and a Wacker makes a big difference.

Other things can come into play. In some boats (Allison, STV, Hydrostream and Baja type outboard potato chip boats, and cats) aerodynamics begin to help. With 140 hp, my Laser ran 68. With a 200 V6 Evinrude, nose cone, jack plate, dual steering, it ran 84 mph any day of the week. So how could 60 hp more give me 16 more mph? I think a more slippery lower, and a "surfacing" engine height helped a lot, but also at 84 the boat was more flying than riding. There was only about a 6" wide by 8" long portion of the pad in the water, so there was almost no water drag. And a this was a 450 lbs rigged (no engine) hull weight.

I don't see a round keel, short strake, twice as heavy, less flyable hull shape running 84. And for the record, I LOVED the V4 Super Strangler engines. When I lived in Houston there was a guy out of Louisiana named Thibideau (or close to it) that raced against fields of competitors of almost total Tower of Power Mercs, and did very well. And the engine sounded like a really pissed off mosquito. It was awesome!

Having said all that, I would say it would take at least 340 wacker hp running a super slippy lower to get to mid-80s.

Greg Guimond

12-24-2013, 10:23 AM

woobs

12-24-2013, 11:00 AM

Three stands for the needed ponies to get 84mph. Hmmmm. Anyone else?

Yup I'm in at just under 300hp. Say, 295hp... using my candy cane slide rule.

mattyboy

12-25-2013, 02:56 PM

or you could get some magic feed corn from this guy, I mean if it will make reindeer fly and get Santa around the world in one night.
just think what it'll do for a 16 .....

Merry Christmas :)

Greg Guimond

12-26-2013, 09:53 AM

Ok you wiseguys lol ................

Twas the day after Christmas and all through the house, there were skeptics a plenty, of Dr Lou’s rouse.
Impossible, improbable, it just can’t be done, even with the wind at Walins back and the Buizilla sun
Instead focus on Fonzi, Abbott and Costello, or Niagra Falls. We’ll say it was gas tank placement, that created the wall.
Matty can’t ask the prop size question, he won’t do the math, different lower units just can’t possibly go that fast
Our Donzi life has been labeled with AQ and E, if we start new learning now, we’ll be more like Ed Donnelly
So they stay in there hovels, afraid to learn more. If they dare step outside it, the Super Strangler may score
I’ll refuse to get data, on old lowers and new, I’ll prove that my thinking is institutional still
They are the archivests, the holder of facts. The numbers are sketchy, because there’s no photo intact
But wait it’s a wacker, it could rev to the moon, I don’t even know the ponies, so better to get my spittoon
All that matters is horsepower, I’m a car motor guy. If I review hydrodynamics, +16 might possibly fly
So woobs sits with his people, the clan with the key. It’s all apples to oranges, umm what’s a Sporty?
Ghost decrees its counting double, that’s just so unfair. I need a new abacus, or at least a T square
The clan they are mumbling at Dr. Lou’s rouse. They know everything and nothing, but remember Mighty Mouse

woobs

12-26-2013, 10:00 AM

Ok you wiseguys lol ................
Twas the day after Christmas and all through the house, there were skeptics a plenty, of Dr Lou’s rouse.
Impossible, improbable, it just can’t be done, even with the wind at Walins back and the Buizilla sun
Instead focus on Fonzi, Abbott and Costello, or Niagra Falls. We’ll say it was gas tank placement, that created the wall.
Matty can’t ask the prop size question, he won’t do the math, different lower units just can’t possibly go that fast
Our Donzi life has been labeled with AQ and E, if we start new learning now, we’ll be more like Ed Donnelly
So they stay in there hovels, afraid to learn more. If they dare step outside it, the Super Strangler may score
I’ll refuse to get data, on old lowers and new, I’ll prove that my thinking is institutional still
They are the archivests, the holder of facts. The numbers are sketchy, because there’s no photo intact
But wait it’s a wacker, it could rev to the moon, I don’t even know the ponies, so better to get my spittoon
All that matters is horsepower, I’m a car motor guy. If I review hydrodynamics, +16 might possibly fly
So woobs sits with his people, the clan with the key. It’s all apples to oranges, umm what’s a Sporty?
Ghost decrees its counting double, that’s just so unfair. I need a new abacus, or at least a T square
The clan they are mumbling at Dr. Lou’s rouse. They know everything and nothing, but remember Mighty Mouse

LOL...very creative :)

duckhunter

12-26-2013, 12:47 PM

mattyboy

12-26-2013, 01:36 PM

greg
very nice that took some time

i guess my feeling is this thread at times becomes comical and uses flawed logic.

comparing apples to bannanas

ed's 16 and mighty mouse both had 4 digit hp and modified hulls or running surfaces. something that has been said not to have happened on lou's boat

then you are saying that weight doesn't have a place in this discussion

you say the strakes aren't in the water and you site bill's 16 which has more weight in the back than lou's by 800lbs, the strakes are almost out of the water at the dock.
my point if lou is out on the biscayne bay i would think he is not out there on fumes and that the tank in the front has plenty of fuel and that the lack of weight in the back and the nose tank is going to make the boat ride at a flatter angle with more wetted surface. more wetted surface is going slower

if you have done any reading on mighty mouse you will see what geoo and the brains at arneson thought about moving weight back on the classic style hull not only to help with the lack of bow lift the arney provides but for higher speeds. the bow lifting capabilites of the ss also need to be proven

there is no way to prove lou's boat but i guess if the feeling is 300 horses will get you to 84 then a baby with the longer strakes should be in the 90s with the same hp that merc 300xs with the shiney little lower should do figure by now some 30 years after they stop making the baby someone would have done it if it is as easy as bolting on an ob

when the owner gets back down to 452 i will have more info.

Morgan's Cloud

12-26-2013, 01:36 PM

Very nice. :eek!:

I'm going to have to start a thread asking how much power it requires to get a 13 Whaler into triple digits.

Maybe it would be more effective to start a thread saying that you know someone who had a friend who said he once had a 13' Whaler that did triple digits. :jestera:

Greg Guimond

12-26-2013, 03:37 PM

All in good fun Matty,

At this point I think you being focused only on #452 as a proper baseline is fine. The only way to verify (and then build upon) the 68mph speed of that 1967 hull is to know what the specifics are on that prop and what RPM the owner is running at WOT. Once you get that info, the numbers will tell a part of the story, but remember only a part.

How much do you think that a fuel tank itself would weigh in a '64-'68 Ski Sporter? How many gallons do they hold? Was it 25 gallons?

mattyboy

12-26-2013, 04:03 PM

i would say with the original 23-25 gallon steel tank with fittings and foam would be around 50-55 lbs bone dry the aluminum probably about the same

the terne tanks were steel but thin the alum were much thicker.

Greg Guimond

12-26-2013, 04:30 PM

Matty, how many horsepower are you going with to get Dr. Lou to 84mph?

I'm at 300hp to do 84mph at-will on any given day with a weedwhacker that will turn way up.

I'm at 280hp to 330hp to get to 84.

I still don't see it although the huge weight difference between a V8 and a Wacker makes a big difference. And for the record, I LOVED the V4 Super Strangler engines. Having said all that, I would say it would take at least 340 wacker hp to get to mid-80s.

I'm in at just under 300hp. Say, 295hp...to reach 84mph

mattyboy

12-26-2013, 04:41 PM

on an unmodified hull short strakes

330-350 for an OB with a "speedmaster" lower and a higher X

450+ for I/O with a raised merc "speedmaster", or surface drive .

Greg Guimond

12-26-2013, 04:53 PM

Matty, how many horsepower are you going with to get Dr. Lou to 84mph?

on a hull short strakes, 330-350 for an OB with a "speedmaster" lower and a higher X

Ok, I'll put you in for 340hp :thumbsup:

Greg Guimond

12-26-2013, 06:56 PM

i would say with the original 23-25 gallon steel tank with fittings and foam would be around 50-55 lbs bone dry. the aluminum probably about the same. the terne tanks were steel but thin the alum were much thicker.

Ok so based on that I'll use 60lbs worse case. Gas weighs 6lbs per gallon. If the tank was 25 gallons total capacity, lets just say that Dr. Lou was running with 10 gallons on that day in 1996. That is 60lbs for the gas and 60lbs for the tank or 120lbs total "worse" case. With these size and type hulls you loose 1mph for each 100lbs of added weight. So my point is that, with respect to the center of gravity difference between 1967 #452 and 1965 OB#1 the effect would be very, very nominal. It would cost Gerry Walin's 1965 only 1mph in comparative speed between the two boats with identical motors.

1 mph. Do you see and agree so we can factor that in?

Greg Guimond

12-26-2013, 08:31 PM

I'm at 300hp to do 84mph at-will on any given day with a weedwhacker that will turn way up.

I'm at 280hp to 330hp to get to 84.

I still don't see it although the huge weight difference between a V8 and a Wacker makes a big difference. And for the record, I LOVED the V4 Super Strangler engines. Having said all that, I would say it would take at least 340 wacker hp to get to mid-80s.

I'm in at just under 300hp. Say, 295hp...to reach 84mph

on an unmodified 16 hull with 55s (short strakes) 330-350hp for an OB, say 340hp

you can't go anywhere on Bisc Bay at WFO for very long on 10 gal

BUIZILLA, how many horsepower do you say it would take for Dr. Lou to clock 84mph?

Greg Guimond

12-27-2013, 07:28 AM

welp.... since nobody knows the actual total gross WEIGHT, with fuel and driver, of whatever Lou was running that day, i'm not even going to guess, much less figure out, any calculations.. there's just nothing here to work with.. :biggrin:

Welp sure we do. The total weight with fuel, driver, motor, and prop is 1500lbs. What horsepower you thinkin for 84mph?

Greg Guimond

12-27-2013, 08:39 AM

1500# ??? that's just a bizarre low number to believe for a 16C... that would put a completely RIGGED hull, without power, fuel, prop, or driver, at wayyyy under 900#?

Huh? Are you counting double? Not bizarre at all. The naked '64-'68 Ski Sporter hulls are 1000lbs with an empty gas tank, everyone agrees including Matty. All the rest adds 500lbs so 1500lbs total.

Soooo ...... horsepower estimate? :rolleyes:

mattyboy

12-27-2013, 09:54 AM

as it seems we are back on weight lets look at where the weight would be

as a note i think a figure of 15-20 gallons is a better estimate from what i recall the gauge fell pretty quick after 1/2 a tank.

1966 16 skisporter with the standard 110 hp volvo aq 200 drive 1500 lbs approx. as stated by the 1966 literature. according to volvo penta documentation the 110 volvo with aq 200 complete weighs 495lbs the tank with 20 gallons would be 180lbs using greg's formula

the balance of the boat would look like e=engine/drive d=driver f = fuelwith tank

e495....d150..f180...

for a total of 1830lbs using the uscg avg weight for an adult of 150lbs for the driver

a v8 i/o like my old one or bill's would look like

e950....d150..f180...

for a total of 2285lbs using an average for published sb v8 aq drives of 950

experimental hull 452

ef590....d150.........

for a total of 1740 using the 1000 lbs for the bare hull and 410 lbs for the 1998 rude 175 and the 180 for the fuel and tank all of which is behind the back seat.

lou's boat

e300....d150..f180...

for a total od 1630lbs using 300 for the ss and the avg formula for driver and fuel.

when thinking of balance the engine weight is behind the rear seat, the driver weight is 4 feet fwd of that and the fuel weight is 3 feet fwd of that.

when thinking wetted surface and keeping the weight of the hull and deck equal in all cases. i can't see how 300 lbs is going to carry 330 lbs plus the weight of the boat that is way fwd

plus in looking for the weight of the ss it looks like the ss with the real slick lower had no shifting so lou when he picked up osiris at the dock would have had to do the mighty mouse paddle.

imo hull 452 has the best weight distribution and lack of weight to get the hull aired out all the weight is behind where the strakes end and keep wetted surface down the next one in line would be the i/o but needs way more hp to run fast

woobs

12-27-2013, 10:24 AM

The truth is that this cannot be proven unless the feat is recreated... ala-"mythbusters"...

It is an interesting (and fun) exercise to try to account for all the possibilities of "the claim" and satisfy ones curiosity for the validity of the claim. But, everything we have discussed has been assumption, guess, estimate, average, comprimise, comparison and conjecture.... all arguably circumstantial and fabricated. It really proves nothing.

It's why we have races (fastest guys are always in the bar) and actually drive for records because, anyone can do it on paper. (You should see what a real salesman can do with a pencil and paper.) So, since it cannot be proven, the culmination of this discussion will serve to re-ASK the question... Is it possible? The answer to each will still be different (as it is now) despite agreements concessions and averages. No consensus.

As another thought, the 84mph really has nothing to do with what really happened on whatever day the claim was made. This is because of many factors including the version of GPS used that day. What was claimed may have honstly been believed to be true on the day but, may not have been. So, the question really is... Can it be done now?

There's only one way to really find out. Anything else claimed will just be ego.

Greg Guimond

12-27-2013, 10:27 AM

as it seems we are back on weight lets look at were the weight would be

experimental hull #452

ef590....d150......... for a total of 1740lbs using the 1000 lbs for the bare hull and 410 lbs for the 1998 rude 175 and the 180 for the fuel and tank all of which is behind the back seat.

Dr lou's boat

e300....d150..f180...for a total od 1630lbs using 300 for the ss and the avg formula for driver and fuel.

Interesting. Take a look at your total weight of 1630lbs for Dr. Lou's 1965 OB#1. The Super Strangler with prop was weighed on a scale at 258lbs not 300lbs so you are down to 1588lbs. As far as fuel, I have never, ever achieved a best mph that full of fuel. I always wait for the needle to drop below the half full mark. So you are 60lbs high there, instead of 180lbs it would be 120lbs. That drops the total weight down to 1528lbs with 10 gallons of gas which could easily become a flat 1500lbs running on vapor.

mattyboy

12-27-2013, 10:55 AM

so lou looks like

e258....d150..f120.... still more weight fwd in my mind to to keep it aired out

and what did we decide could lou backup or was he just going fwd. if he was shifting the whole lower discussion gets thrown out

Greg Guimond

12-27-2013, 11:10 AM

Are we in agreement Matty that we are now using 1525lbs total weight up from 1500lbs?

Greg Guimond

12-27-2013, 11:14 AM

1500# ??? that's just a bizarre low number to believe for a 16C

You were right, 1500lbs is too low, it is actually 1525lbs :wink:

mattyboy

12-27-2013, 11:38 AM

no mixed gas is heavier and i don't see anyone that light on fuel in that area of boating. bays ocean running means that running on vapor would not be too smart. removing weight might also be fine for paper running but i know when mine got light on gas 1/4 or so it became a handful in rougher water. i would imagine lou's would do the same on the bay.

i have read the thread on scream and fly most estimates put the ss under 175 hp and the really slick lower had no shifting so that would make it a pleasure around the docks seems lou should remember that

so we need to button those two up.

duckhunter

12-27-2013, 11:41 AM

yup, i'm still in Missouri :kingme:

The truth is that this cannot be proven unless the feat is recreated... ala-"mythbusters"...

There's only one way to really find out. Anything else claimed will just be ego.

Yup, interesting discussion while the boat is sitting in the shop for the winter, but ultimately an exercise in mental masturbation.

Let's strap a 300 on The Mule, weigh it, and run it.

Greg Guimond

12-27-2013, 11:46 AM

no mixed gas is heavier and i don't see anyone that light on fuel in that area of boating. bays ocean running means that running on vapor would not be too smart. removing weight might also be fine for paper running but i know when mine got light on gas 1/4 or so it became a handful in rougher water. i would imagine lou's would do the same on the bay.

Just want to clarify first, are you agreeing with 10 gallons of fuel and 1525lbs total weight for 1965 OB#1?

mattyboy

12-27-2013, 11:48 AM

no i don't agree

Greg Guimond

12-27-2013, 11:53 AM

The truth is that this cannot be proven unless the feat is recreated. As another thought, the 84mph really has nothing to do with what really happened on whatever day the claim was made. This is because of many factors including the version of GPS used that day. What was claimed may have honstly been believed to be true on the day but, may not have been.

woobs the point you make on GPS is a great one. Lou said it was 1996 when the Garmin took the reading. Was GPS accurate then?

Greg Guimond

12-27-2013, 12:06 PM

no i don't agree with 10 gallons and 1525lbs

That's cool although I run exclusively in bigger water and the Ocean and being light on fuel is no biggie provided I know where I am, which most often is LaLa Land! I can say in decades of performance boating I never went to chase the big # with a full tank of gas.

Do you want to say Lou carried a full tank of 20 gallons and the total weight was then 1585lbs?

woobs

12-27-2013, 12:46 PM

woobs the point you make on GPS is a great one. Lou said it was 1996 when the Garmin took the reading. Was GPS accurate then?

Upgraded mid 2000.

if your down to one pound at at a time....You could say 12.5 gallons... mid point compromise. Was the weight of the tank included in the 1000 pounds estimate. Do wackers use a regular size battery... or a motorcycle sized one. That might make some difference.

Greg Guimond

12-27-2013, 01:13 PM

duckhunter

12-27-2013, 01:43 PM

So maybe Dr. Lou is not telling a lie woobs and he did see the Garmin read 84mph in 1996. I just don't see the guy making up so much of the story but if the GPS system was a bit suspect in 1996 and was not upgraded until 2006 perhaps it was giving him the reading that he relayed.

The GPS constellation in 1996 had a full 24 birds but it was limited by Selective Availability (dropped in 2000) in civilian use. SA had more of an effect on location precision vs. measurement of velocity. The precision of GPS has certainly improved in the last couple of decades, but I would argue that it probably didn't induce much of an error in Dr. Lou's measurements. As long as he had at least 3-ball coverage (which he almost certainly did on the eastern seaboard of the US) he should have gotten a measurement within a mph or two.

Ed Donnelly

12-27-2013, 01:48 PM

my pencil is faster than your pencil...

it's longer, has more lead, and it weighs less too

:spongebob:

Only because your pencil was custom made and the wood was Balsa

BG ????

Ed

mattyboy

12-27-2013, 04:18 PM

I would say 1600 is my bottom line on lou

and mixed gas at 6.50 lbs a gallon

mattyboy

12-27-2013, 04:45 PM

wonder what one of these kitchenaid eggbeaters would do on a baby

:eek!:

http://www.youtube.com/watch?v=azh0ycJa4Pw

woobs

12-27-2013, 05:18 PM

The GPS constellation in 1996 had a full 24 birds but it was limited by Selective Availability (dropped in 2000) in civilian use. SA had more of an effect on location precision vs. measurement of velocity. The precision of GPS has certainly improved in the last couple of decades, but I would argue that it probably didn't induce much of an error in Dr. Lou's measurements. As long as he had at least 3-ball coverage (which he almost certainly did on the eastern seaboard of the US) he should have gotten a measurement within a mph or two.

Yep, 24 birds working world wide from 1995. Generally, 4 or more satellites required for accuracy. Prior to mid-2000, signal degredation issues could affect speed readings up to 4 mph. Even todays upgraded 2013 system has an error factor od 0.5mph using 9 or 10 satellites. Early GPS units were susceptable to many errors (hardware, software and the GPS satellite system itself).
So system error plus hardware/software error...who knows what that was but, it could have been more than 4 mph.

Some common factors affecting GPS:
Ionosphere and troposphere delays - The satellite signal slows as it passes through the atmosphere. The current GPS system uses a built-in model that calculates an average amount of delay to partially correct for this type of error.

Signal multipath - This occurs when the GPS signal is reflected off objects such as tall buildings or large rock surfaces before it reaches the receiver. This increases the travel time of the signal, thereby causing errors.

Receiver clock errors - A receiver's built-in clock is not as accurate as the atomic clocks onboard the GPS satellites. Therefore, it may have timing errors.

Orbital errors - Also known as ephemeris errors, these are inaccuracies of the satellite's reported location.

Number of satellites visible - The more satellites a GPS receiver can "see," the better the accuracy.

Satellite geometry/shading - This refers to the relative position of the satellites at any given time. Ideal satellite geometry exists when the satellites are located at wide angles relative to each other. Poor geometry results when the satellites are located in a line or in a tight grouping.

Intentional degradation of the satellite signal - Selective Availability (SA) is an intentional degradation of the signal once imposed by the U.S. Department of Defense. SA was intended to prevent military adversaries from using the highly accurate GPS signals. The government turned off SA in May 2000, which significantly improved the accuracy of civilian GPS receivers.

Maybe Dr Lou saw 84 and I would never call him out on it... but it might not have been 84. We think Radar was accurate (read unfallible) and it is almost.... but you can still clock a tree moving 30mph when the wind is blowing the leaves.

woobs

12-27-2013, 05:36 PM

He has a much heavier back end than a wacker would but still the inner 55's are not playing any role at all.

Actually, I think the lack of inner strakes is playing a huge role. In the picture you can see the "splash line' (blue)78545
moving up the hull and missing the inner strake. At the outer strake the water travelling up the hull is shed to the air. This leaves a rather large wetted surface. IF the inner strakes were extended the splash line travelling up the hull would be ejected earlier reducing the size of the wetted area and associated drag.

This is another reason why a hull with longer inner strakes would be faster and have a better top end.

woobs

12-27-2013, 06:17 PM

My woodyboat has no strakes. And as such has a soft ride but, it has a tough time at the top end when compared to similar sized/powered plastic boats (with strakes).

My 18' 238HP 4.3 Greavette is about 12-15 mph slower than my buddies 18' 205HP 4.3 fiberglass boat. At first we thought it was weight.. but my woody boat is only 2,290 and his is actually heavier at 2,450.

In the picture below you can see the splashline move up the hull and get ejected at the chine.
The diagram shows the particulars of what is going on.7854678547

Greg Guimond

12-27-2013, 06:21 PM

I would say 1600lbs is my bottom line on Dr lou's 1965 16 total weight

Man you guys drive a hard bargain! I don't know if 1600lbs will be accepted by BUIZILLA, he's still smartin from not sharpenin his longer pencil and weighing his own 16 OB hull naked :biggrin:

So to get to 1600 lbs we now have ..........

1,000 lbs for the naked 1965 OB#1 with 55's and a dry 20 gallon gas tank
258 lbs for the 1975 Evinrude Super Strangler race motor with lower unit and prop
150 lbs for Dr. Lou or Gerry Walin grinning ear to ear
98 lbs for 15 gallons of pre-ethanol high test pre-mixed fuel at 6.5lbs per gallon
92 lbs for misc rigging
2 lbs for a 1 lb bag of winter bench race banter

I'll give you 1600lbs but I have to tell you that when I see my hull weigh in at 1107lbs I'm having a really hard time thinking that a "lighter layup" 1964-1968 hull is only 107lbs less. I have nothing but extra weight in my build up. When (and if) woobs weighs his 16 next year I'm going to say it clocks 900lbs.

Onward.......1600lbs it shall be :wavey:

dsparis

12-27-2013, 06:36 PM

From boatracingfacts.com

The above is correct, actually the first v4 race motor was the Johnson GT115/Evinrude X115 (model # GT10S) introduced in 67, then OMC spent 2 years prototyping before introducing the Stinger/SS (Model # KC13R), then a year of prototyping again before introducing the Stinger GP/Super Strangler (model KR15M).

Horsepower wasn't officially rated on any of these but the grapevine reports I had seen and heard were:

GT10S-116
KC13R-128
KR15M-155

-at the crank.

KR15M had forged cranks and pistons and added rollers to the bearings which really added durability. GTs and KCs had a lot of issues with cast cranks and heavy cast pistons with snap ring clips and ring dowels that would work their way out.

So, it was only 155 hp ? 84 mph ?

Greg Guimond

12-27-2013, 06:49 PM

Those horsepower #s are wrong for the later model Super Strangler and Stinger GP race motors. More to follow on that. The last motors were in OMC Brugge being raced alongside the CCC.

mattyboy

12-27-2013, 07:10 PM

for the record here is the boat that was featured on the powerboat cover

you can see with the woman sitting in the bucket seat facing backwards were the confusion of an 18 with lounge seating came from

oh BTW high 50's was all this 18 OB rigged by OMC could do before they say "" it ran out of hull"

hull number 18-390

Greg Guimond

12-27-2013, 07:23 PM

Greg, if you keep moving the goal posts your going to have more mole holes in your story than swiss cheese in Wisc. 150# for a driver???? come on, man, he was an adult not a 5th grader

Hey I already conceded 100lbs to Matty for no real reason, that is 1mph. Give it back to me and your driver can be an over fed soda drinking 250. I hope I did not just insult someone........:wink:

Are you ready to pony up a horsepower # yet? Let me guess, it'll start with a 3 :outtahere:

dsparis

12-27-2013, 07:32 PM

78549

Greg Guimond

12-27-2013, 07:46 PM

at 1600# it would take a solid 275-280 hp at the prop at 6800-7000 rpm using a 13.25-13.5" dia wheel with superior blade technology.

Holy crap, I think I just got BUIZILLA to commit to two numbers! 1600lbs all in and 280hp for Dr Lou to run 84mph. Next I'll get a phone call from Dr Lou with a picture of the under deck scribble. :lightning

Greg Guimond

12-27-2013, 07:49 PM

78549

So what horsepower am I putting you down for to get the 84mph? I might as well stack 'em and rack 'em.

dsparis

12-27-2013, 08:33 PM

Maybe the good Dr. filled all the storage areas with helium balloons to lighten it up :jestera:Sorry just can't see that hull doing 84 even with modern tech.

Greg Guimond

12-27-2013, 08:35 PM

And so what horsepower # do you think it would take?

duckhunter

12-27-2013, 08:38 PM

Yep, 24 birds working world wide from 1995. Generally, 4 or more satellites required for accuracy. Prior to mid-2000, signal degredation issues could affect speed readings up to 4 mph. Even todays upgraded 2013 system has an error factor od 0.5mph using 9 or 10 satellites. Early GPS units were susceptable to many errors (hardware, software and the GPS satellite system itself).
So system error plus hardware/software error...who knows what that was but, it could have been more than 4 mph.

Not gonna argue GPS issues any further, but I maintain that even in '96 if he had at least three birds in view (very probable in CONUS) he could get a fairly accurate doppler ground speed +/- 2mph. Particularly in a straight line at a consistent elevation and at a relatively high speed. Shoot, we were stuffing supersonic cruise missiles in people's bedroom windows in '91 using slightly better technology with fewer spacecraft available.

Bottom line, the 84mph number is the one that got thrown down (along with the 150# metrosexual hipster, apparently). :tooth:

woobs

12-27-2013, 09:23 PM

I'm not saying it was 84mph, I'm not saying it wasn't 84...I'm saying there is a lot of room for doubt there and sometimes not everything is as absolute as we think it is.

In 91 the US military had acurate use of GPS. Signal degredation was built in the GPS system so other military organizations (countries) did not have the benefits the US military had. This practice ended in May of 2000 when consumer use was up graded. And this is but one instance that may account for erroneous readings.

I will weigh my hull/deck in the spring. The hull will be accurate as it is pretty much factory. The deck however will not be accurate as it has already been re-cored and sports a heavier layup.

Greg Guimond

12-28-2013, 03:48 PM

for the record here is the 18 Classic boat that was featured on the powerboat cover in 1971

you can see with the woman sitting in the bucket seat facing backwards were the confusion of an 18 with lounge seating came from

oh BTW high 50's was all this 18 OB rigged by OMC could do before they say "" it ran out of hull"

hull number 18-390

Very cool in yellow. Can you post the article's content itself?

Greg Guimond

12-29-2013, 08:17 AM

Not gonna argue GPS issues any further, but I maintain that even in '96 if he had at least three birds in view (very probable in CONUS) he could get a fairly accurate doppler ground speed +/- 2mph. Particularly in a straight line at a consistent elevation and at a relatively high speed.

This explanation of GPS in 1996 is very complete so that takes the validity of Dr. Lou's technology off the table.

1967 OB#1 weight is now agreed to by all at 1600lbs worse case. woobs will weigh his 16 in the spring to validate 1000lbs. I'm still goin with 900lbs
GPS technology now agreed by all that in 1996 it was accurate and capable

Prop technology?

Greg Guimond

12-29-2013, 08:31 AM

I'm taking prop technology as a neutral, even Ghost thinks so...........

I agree the lower is worth more than 3 mph. I could see 7. There's no way the prop technology was better than what is available today. Best it could be is as good as the best today.

And it looks like Walin had just a few wheels available to him .........

Carl, I think you might be right on the year being 1971. That was the last year that I raced and Gerry Walin may have been using more than one setup at that time, I remember his trailer sure had a lot of motors and more props than I had ever seen in one trailer with the possible exception of Ted May. If I remember right Gerry was running his Kilo setup at the Divisional and I think he had just upped the kilo record (98mph?) It was the first time that I had seen bounce pipes. Gerry and I had the longest boats of any of the AOH's at the time. Jerry

Greg Guimond

12-29-2013, 08:57 AM

So what's left? How about the strake bake again? 55's versus 21's and what three feet of additional inner lifting strake is worth at 59mph and above in a 16 Donzi.

Greg Guimond

12-29-2013, 09:04 AM

BUIZILLA, does your 1996 16 OB also have 21's or did they change the inner strake length again for those five boats? Also, are they still at 31" apart width?

woobs

12-29-2013, 10:11 AM

This explanation of GPS in 1996 is very complete so that takes the validity of Dr. Lou's technology off the table. GPS technology now agreed by all that in 1996 it was accurate and capable

Hold on there Skippy...

Just because you post it 3 times it majically does not become more accurate. What's agreed (because it's published fact) is that GPS in 1996 had systematic built-in error for anyone except the US military. So unless Dr. Lou was "borrowing" government equipment that day it is fact that an amount error existed. Accurate? Sure, within the parameters of error known to exist at the time.

How much error? Somewhere between the 0.5 mph as current equipment to 4mph in the system (of the day) alone. Then adding additional error for the plethora of reasons previously posted maybe another 1-2mph....for a possible variance of 0.5 to 6mph.

So Check? I hardly think so and certainly not for the purpose of this discussion when the accuracy of the weight of fuel is discussed with a 0.5lbs varience and agreement of some conditions must be pinned at 1mph! So, why not apply the same standards to the system of measurenment?

FWIW, I'm sure it was definately more accurate than an on board hull mounted speedometer... a (circa 1996) recreational hand held radar or using a stopwatch as you pass the pier....

woobs

12-29-2013, 10:22 AM

Greg Guimond

12-29-2013, 10:34 AM

Hold on there Skippy...

Just because you post it 3 times it majically does not become more accurate. What's agreed (because it's published fact) is that GPS in 1996 had systematic built-in error for anyone except the US military. So unless Dr. Lou was "borrowing" government equipment that day it is fact that an amount error existed. Accurate? Sure, within the parameters of error known to exist at the time.

How much error? Somewhere between the 0.5 mph as current equipment to 4mph in the system (of the day) alone. Then adding additional error for the plethora of reasons previously posted maybe another 1-2mph....for a possible variance of 0.5 to 6mph.

So Check? I hardly think so and certainly not for the purpose of this discussion when the accuracy of the weight of fuel is discussed with a 0.5lbs varience and agreement of some conditions must be pinned at 1mph! So, why not apply the same standards to the system of measurenment?

FWIW, I'm sure it was definately more accurate than an on board hull mounted speedometer... a (circa 1996) recreational hand held radar or using a stopwatch as you pass the pier....

Sorry woobs, I'm going with duckhunter. He seems to be very comfortable that GPS worked in 1996 and very comfortable with the location in the US :yes:

Greg Guimond

12-29-2013, 10:40 AM

As far as the continuing strake bake...

I`m pretty confident that I`ve shown the lack of inner strakes in the last 55 inches leads to a significantly increased wetted surface. (see posts; 674-675)

To quantify this you`ll have to figure out how much area is wetted between the short strake and long strake version for a given speed. Then we must quantify the amount of drag for the wetted surface of each hull at that speed. Calculate the difference, convert to estimated mph equivilent then account for the power required to overcome the drag difference to achieve the target speed.

That`s a lot of math....probably a thesis (or two) worth.

On the strake bake and 55s versus 21s I have to look back in my design notes from when we were noodling through hull bottom options. I am 100% agreeing with you that having 21's instead of 55's helps you with acceleration and lower speed lift. I just want to check a couple of things from when Jim Russell and I spoke.

Also, BUIZILLA's inner strakes on his 1996 OB could be a totally different length?

woobs

12-29-2013, 10:43 AM

Props.

I have no doubt that the racing props of the day used on the SUPER Strangler were of cutting edge design. I don`t believe that they were as good as what is available today but, as purpose built units they gotta be real good by any standards.

Do we know which prop Dr. lou used in 1996. Given that Gerry Wallin had a whole trailer full of props we can estimate that they were pretty specific in design and most likely sensitive for set up. What do you think the chances are that Dr. Lou had the exact prop required for the perfect set up in 1996 when Gerry Wallin needed a whole trailer of props to dial in his racing set up.

woobs

12-29-2013, 10:55 AM

1965 Ski Sporter boat weight .......... check
1996 GPS technology ......................check
Propeller technology .......................check

Possible 84mph? ............ priceless :bighug:

1965 Ski Sporter boat weight .......... reasonable estimate.
1996 GPS technology ......................nope
Propeller technology ....................... wishful
Inner strakes.................................. unaccounted for
SUPER Strangler HP.......................... 175Hp + unknown
SUPER Strangler Cd......................... guesstimated
Clostest comparison......................... inaccurate

Possible REAL 84mph ?..................... I wouldn`t bet the farm.
:nilly:

Greg Guimond

12-29-2013, 11:06 AM

Sorry woobs, I'm going with Ghost on the props being equal. That one is off the table but I'm with you on the strake bake and 21s v 55s, have to check that a tad.

Edit: The closest comparison is #452 which everyone agrees to, so that one is off the table as well. Sorry.

Ghost

12-29-2013, 11:09 AM

I'm taking prop technology as a neutral, even Ghost thinks so.

More precisely, what I said was that the prop technology was NOT better then than now.

That said, I didn't notice anything in this thread which clearly documented which modern props people ran in the various benchmark runs being cited. Can imagine the absolute best speed prop might be lousy all-around, so without clear info, who knows how close to the fastest-available-prop-at-the-time any given benchmark run actually used.

Not sure any of that was in English.

woobs

12-29-2013, 11:23 AM

Sorry woobs, I'm going with duckhunter. He seems to be very comfortable that GPS worked in 1996 and very comfortable with the location in the US :yes:

Well, I suppose you can negotiate your premise to 84mph but, it does not mean it ever happened or ever could. I thought this was a reasonable exercise that actually accounted for the information put forth, and attempted to quantify the factors that might support (or refute) an early Ski Sporter with a modified Super Strangler reaching a top speed of 84mph.

If you are just going to ignore real information and at the same time claim maximum benefit of circumstantial evidence in all areas of estimations and negotiations while continually posting a moving target.... Well winter blahhhhs or not, this has become just a fantasy quest.

Greg Guimond

12-29-2013, 11:32 AM

duckhunter

12-29-2013, 11:39 AM

Still a whole lot of "what ifs" to account for. The prop pictured is certainly sexy, but I've got three or four props hanging in the shop that are sexy as hell and still don't work on my boat.

As far as GPS goes, I have been purposefully vague and kept everything in the realm of what is already in the public domain. To clarify a little, I mentioned in my first post that Selective Availability (SA) was indeed a factor in 1996 for civilian use, but that it affected position accuracy much more than ground speed. Speed is a straightforward doppler measurement between the handheld instrument and multiple spacecraft. Given a constant elevation (sea level or thereabouts), over an extended period (multiple tens of seconds), at a relatively high speed (multiple tens of mph), in the eastern US (multiple ball coverage), it is very likely that the speed over ground measured by a relatively primitive device was accurate enough for our purposes here.

In my mind the bigger question is can a relatively inefficient round-keel deep-V hull like the 16 hit 80+ mph with the outboard technology of the time? I think it would be a feat with a modern screamer like the 330+ crank hp black motor, and I'm not convinced that it was possible with the now-infamous "super strangler." I'm still sitting on a dock in Missouri with Buizilla, but I wouldn't mind being proven wrong.

duckhunter

12-29-2013, 11:45 AM

It does account for the info put forth woobs.

Now before I check my Jim Russell notes, I'm taking a look at Bill's great picture at 65mph. If a Super Strangler weighs 258lbs, how much more does Bill's I/O set up weigh above that? With that additional car motor weight removed from the boat how much higher would the hull ride at the same 65mph? It would have to be a higher ride, but who knows by how much :screwy:

Weight is also way farther back with the whacker. The 16 looks to be running out of hull already, even with the cast iron lump in the bilge. You guys are smarter on this stuff than me, but I personally wouldn't want to be fighting the round keel at high speed. That said, I grew up with pads so maybe there's a trick to it.

dsparis

12-29-2013, 11:49 AM

woobs

12-29-2013, 11:58 AM

It does not account for potential error in the measuring system. You just decreed 0% error on GPS and 84mph in absolute. not so. Moving on....

The reason for the strake debate is because of the comparison of a 225 Hp boat with longer strakes travelling 74mph vs one of unquantified Hp and shorter strakes being able to do the same. This presumably at the same or similar cost in power and thus, the comparison.

As Bills picture showed the strakes clearly above the water level you concluded that at this speed the strakes are out of play and serve no purpose. I have shown this to be incorrect. Without a quantitative hydrodynamic study of the two hulls the comparison is not valid. We can`t use the 74mph boat in the discussion.

The question of how much wetted surface on a heavier boat vs. a lighter one of the same design and at the same speed is a different animal. As presumably some amount of a V hull has to be in the water. I think the difference in this instance is real but, again very difficult to quantify. It is difficult to ascertain the ride height (and therefore the wetted surface) difference and how significant that is in relation to the drag.

Greg Guimond

12-29-2013, 12:04 PM

I talked to a buddy of mine this a.m. who raced an allison (he races stv's now) with a factory prepared and sponsored super strangler. The best they EVER saw was 82. Think about that. 82 in a purpose built race boat. He agrees that no way no how did that 16 ever see 84.

I'm still hovering at 50% on Dr Lou. If he only saw 82 in an Ally than something is wrong with that, it seems low. Ask him what year the Super Strangler was and what lower he had on it.

How many horsepower do you think it would take to push Dr Lou to 84 dsaparis?

Greg Guimond

12-29-2013, 12:10 PM

As Bills picture showed the strakes clearly above the water level you concluded that at this speed the strakes are out of play and serve no purpose. I have shown this to be incorrect. Without a quantitative hydrodynamic study of the two hulls the comparison is not valid. We can`t use the 74mph boat in the discussion.

The question of how much wetted surface on a heavier boat vs. a lighter one of the same design and at the same speed is a different animal. As presumably some amount of a V hull has to be in the water. I think the difference in this instance is real but, again very difficult to quantify. It is difficult to ascertain the ride height (and therefore the wetted surface) difference and how significant that is in relation to the drag.

woobs, simple question for you. If you took Bill's boat with his current set-up, and ran 65mph, and then you took out his car motor and I/O drive completely and installed a 258lb Super Strangler do you think the boat would ride higher or lower at the same 65mph on the same day with the same fuel?

Simple woobs, higher or lower ?

mattyboy

12-29-2013, 12:10 PM

It does account for the info put forth woobs.

Now before I check my Jim Russell notes, I'm taking a look at Bill's great picture at 65mph. If a Super Strangler weighs 258lbs, how much more does Bill's I/O set up weigh above that? 500lbs, 600lbs more? I don't remotely know the answer to this one. With that additional car motor weight removed from the boat how much higher would the hull ride at the same 65mph? It would have to be a higher ride, but who knows by how much :screwy:

with lack of weight in the back the 16 would be higher in the back but LOWER in the front and would bow steer, stern lift or having the nose lower than the back is deadly in a 16. volvo v8 application ranges from 800-1000lbs so say 550 to 750 lbs which would totally shift the balance of the boat to the front.

woobs

12-29-2013, 12:21 PM

woobs, simple question for you. If you took Bill's boat with his current set-up, and ran 65mph, and then you took out his car motor and I/O drive completely and installed a 258lb Super Strangler do you think the boat would ride higher or lower at the same 65mph on the same day with the same fuel?

Simple woobs, higher or lower ?

If Bills boat were majically lighter, and the angle of attack were able to be maintained I would expect it to ride higher. How much higher... I don't know. How significant this would be in regards to drag... I don't know. There is a finite limit and the issue of dimishing returns as SOME of the hull must remain in the water

In terms of a planing hull, Is it possible that ride height varies with speed and not weight? That two boats both at 65mph have the same ride height but require different power output to maintain that height? I don't know.

Greg Guimond

12-29-2013, 12:26 PM

If Bills boat were majically lighter, and the angle of attack were able to be maintained I would expect it to ride higher. How much higher... I don't know. How significant this would be in regards to drag... I don't know. There is a finite limit and the issue of dimishing returns as SOME of the hull must remain in the water

In terms of a planing hull, Is it possible that ride height varies with speed and not weight? That two boats both at 65mph have the same ride height but require different power output to maintain that height? I don't know.

Thanks, exactly, the answer is higher.

woobs

12-29-2013, 12:39 PM

Thanks, exactly, the answer is higher.

Okay, higher. How much higher? If, say 550lbs lighter...what is the difference in the amout of wetted surface? How much less drag does this equate to? What is the difference in power required at this speed? Are any of these differences significant? How significant?

Greg Guimond

12-29-2013, 12:53 PM

Ghost

12-29-2013, 12:54 PM

Matty makes a good point. There is no such thing as simply riding 'higher' by removing weight from the stern. If one could remove weight throughout the boat such that angle of attack remained unchanged, lighter means higher. If one removes weight but moves the centroid significantly forward, the result is less clear.

This is most commonly observed with boats floating at rest. We usually talk about boats sitting low but it's actually stern-low, bow-high. Single vs twin models of the same hull illustrate this well.

So, while lighter should generally mean higher, it could be more complex.

Ghost

12-29-2013, 01:15 PM

Side item, per someone else's point above, who knows what happens to stability with a round keel and only a small amount of hull in the water. I *believe* one of our own went pretty flipping fast in a 16, and lengthened the strakes for stability.

woobs

12-29-2013, 01:53 PM

I know that you seem to like the benefit of a Cray and MIT in this thread so we'll never know precisely. However, I think at one point Matty and Jay were comparing notes on how squat there two 16s sat at rest at the dock. I could be wrong but I thought it was those two guys. I would guess it is fairly substantial.

I think the difference is substantial at rest and at lower speeds. But the hull can only rise to the point of coming out of the water to be airborne. The amount of power required to do this is tremendous and way past anything we are discussing here.

So, as we approach the maximum height the hull can rise; any increases towards this height are higher up the curve and the forces required to do this increase exponentially (diminshing returns). The difference in height that 550lbs gravity imposes acting against the lifting force from the water resistance on the hull, generated at high speed (close to maximum height) by the drive are not very much at all, and more insignificant the closer you get to maximum height.

This is definately more complex when a change in weight distribution is taken into account. The trim angle of the drive may need to be increased for correction, which also increases drag and decreases the efficiencies of the prop. As more energy is expended to maintain the angle of attack, there is less available for forward propulsion.

...very complicated indeed.

For arguments sake, I'd say that the ride height is near maximum in any case this close to the limits of the hull, and the height difference while real, is negligible. (even easier to say when we can't measure it).

This is a techncal discussion after all. You may need a supercomputer and a big brain to get the exact numbers however, common sense , logic and some reasonable powers of analysis can usually suss things out and put you on the right path.

Greg Guimond

12-29-2013, 02:13 PM

The 16 hull can only rise to the point of coming out of the water to be airborne. The amount of power required to do this is tremendous and way past anything we are discussing here. So, as we approach the maximum height the hull can rise for a given speed, increases in this height are higher up the curve and the forces required to do this would increase exponentially. The difference in ride height that 550 additional lbs imposes acting against the strakes lifting force resistance on the hull, generated at high speed may not be too great.

I agree that we are NOT talking about the hull being fully airborne so move that aside for the moment.

Let's say for chits and grins that Bill's car motor short strake 16 would ride 3" deeper at 65 mph than the exact same hull with a 258lb Super Strangler wacker on the backer. 3 inches deeper. His picture shows that the inner strake 55s are already well out of the water at 65mph. Not just touching spray water but well out, perhaps by 6" plus. So say that 55's just became 49s. Now, if you pulled his picture UP magically by 550lbs of weight (or 3") at that speed, what would the 49s further drop down to if the angle of attack remains at the same 9/10 degrees?

Put that in the CRAY .............

Greg Guimond

12-29-2013, 02:19 PM

The higher res shot of Bill hauling the mail ............

mattyboy

12-29-2013, 02:39 PM

what has sealed this in my mind is my hornet project with the motor and drive in I could pick the nose up and move the trailer by hand with the motor and drive out I could not lift the nose.

jay's 16 was not as azz heavy as mine his is a 302/200 mine was a 351/250 mine also had the battery in the back on the port side so mine sat lopsided at the dock.

if you look at the water line on the drives you can see mine sat an inch or so lower than jay's on jay's you can see the shift cover screw

here are a few pics

mine jays and mine running

woobs

12-29-2013, 02:39 PM

[QUOTE=Greg Guimond;647041]Let's say for chits and grins that Bill's car motor short strake 16 would ride 3" deeper at 65 mph than the exact same hull with a 258lb Super Strangler wacker on the backer. 3 inches deeper. His picture shows that the inner strakes are already well out of the water at 65. Not just touching but well out, perhaps by 6" plus. So say that 55's just became 49s. Now, if you pulled his picture UP magically by 550lbs of weight (or 3") at that speed, what would the 49s drop down to if the angle of attack remaining at the same 9/10 degrees?/QUOTE]

First of all, I think 3" is way too optimistic at speed. 1" (or less) at speed...maybe.

Secondly, out is out. At 65mph out at 55" and out at 49" regardless of the increase in ride height. This hurts your case as there is no edge to break the adhesion of the water to the hull (and eject it to the air) until the outer strake. You can see in the picture the wetted surface is there. The drag is there. Bills 430Hp can push it to 65 though.

note** In Mattys 3rd pic above you can see the spray coming off at the outside strake (and the pressure line up to that point)

Greg Guimond

12-29-2013, 03:07 PM

here are a few pics, mine, jays and mine running

Matty how fast are you going in that picture? Do you remember what your WOT speed was. Also, for the AQs that have trim, anyone know how many degrees was stock? Was it 10 degrees before you hit tilt?

Greg Guimond

12-29-2013, 03:12 PM

Doc, ran his big number in salt. we all know salt is more BOUYANT than fresh...

Yessiree, salt water is faster than fresh water, everyone agrees with that. How you makin out with that prop depth against keel on that never weighed naked '96 ya got there :rofl:

mattyboy

12-29-2013, 03:22 PM

Matty how fast are you going in that picture? Do you remember what your WOT speed was. Also, for the AQs that have trim, anyone know how many degrees was stock? Was it 10 degrees before you hit tilt?

as far as I remember that was the third hole and about 45 mph with an ultra just about 50 was wot before the boat became uncontrollable. I was tucked in behind another boat letting them flatten the water for me. the ultra had issue ventilating and blowing out in rough stuff

on the 280 t it will let you set the trim anywhere there is no preset trim/ tilt/trailer range point like on the modern stuff, not sure a 290 setup.

Ghost

12-29-2013, 03:23 PM

Agreed, 3 inches higher at speed sounds absurdly above reality without the bow going way down and the wetted surface moving many feet forward.

The pressure area times the pressure gives a force, a good chunk of which is lifting the boat out of the water. At speed, with a small pressure area, the pressure is relatively very high. A small change in height corresponds to a significant change in pressure area and thus in force to compensate for the weight change.

I'd expect less than an inch rise at the transom if the attitude doesn't change a lot.

Also, all those factors about changing trim and prop angle might be very significant. The trim part I'd thought about but I hadn't considered prop efficiency based on changing angle of attack. Good thought.

Greg Guimond

12-29-2013, 03:37 PM

mattyboy

12-29-2013, 03:42 PM

here is a pic with the solas on it at about 55 could run up to 60 and the best was 62 the boat ran flatter with more wetted surface but was stable and predictable

Greg Guimond

12-29-2013, 03:52 PM

First of all, I think 3" is way too optimistic at speed. 1" (or less) at speed...maybe. Secondly, out is out. At 65mph out at 55" and out at 49" regardless of the increase in the hulls ride height. note** In Mattys 3rd pic above you can see the spray coming off at the outside strake

as far as I remember that was about 45 mph with an ultra, just about 50 was wot. I was tucked in behind another boat letting them flatten the water for me.

woobs do you want to use 1" then? Now onto "out is out". We have already agreed that 55s are completely out of the water at 65mph. In fact, at 65mph, 49's would just be touching. That is your baseline. Baseline = 49's and 65mph with 500lbs extra.

Even if Bill was the donor boat (forget for the moment the wacker) each additional MPH he added in speed (think blower) would place slightly less hull in the water.

Do you agree with me on this? Again, all other items are the same. Gas, conditions, prop, Bills cajones, etc etc. Do you agree?

Morgan's Cloud

12-29-2013, 03:58 PM

And speaking of salt ..

Something's been going through my mind for a few days now and it hasn't come up yet.

84 , if possible in a 16 , is way past the point of what they were engineered/designed for in terms of the hydrodynamic and aerodynamic forces at work on the hull and deck. Such a speed in such a small boat could surely only be attained on a very safe and smooth surface. I'd say even smoother than the water in Bill's great photo.

Biscayne Bay is a pretty exposed and large area of water for a 16 footer before you even factor in wakes from other boats and weather.

It would take , I imagine , a good while for a Super Strangler to build up enough of a head of steam to wind a 16Classic out completely. So it's not going to happen with a quick jab of the throttle .

There's a huge difference between driving , say , an older classic Cig 35 at 84 and a Donzi 16 .

Could it be safely done on Biscayne Bay because it would hinge on a one in a million day that was glass calm and no other boats around to cause disturbance ?

Greg Guimond

12-29-2013, 04:03 PM

Is Biscayne Bay similar to Long Island Sound and New York Harbor?

Ghost

12-29-2013, 04:20 PM

So do we agree on 1" "higher" then?

Not exactly, no, but what would (could?) it even matter for your swaggy avalysis if 1" is believed to be about right? Not sure where you'd try to plug that number in at the front end of any calculation that would be meaningful?

So, let's assume it is accurate, then what?

Morgan's Cloud

12-29-2013, 04:23 PM

If Jim would get up off the dock in Wisconsin or wherever it is and come to the computer for a minute I have a feeling that he would know best .

(that was in reference to the conditions on Biscayne Bay seeing the post didn't appear directly under Greg's question)

duckhunter

12-29-2013, 04:33 PM

Is Biscayne Bay similar to Long Island Sound and New York Harbor?

Never boated in the LIS or NYH, but I GUARANTEE that none of them are as glassy as the TN River. Get the mule rigged up and drag it to 'Bama and I'll throw some beer in the shop fridge. We can dunk her right down the road.

78562 78563

Greg Guimond

12-29-2013, 04:33 PM

Not exactly, no, but what would (could?) it even matter for your swaggy avalysis if 1" is believed to be about right?

Not exactly? I thought you were an MIT guy as well. And as I said to BUIZILLA none of this matters, but it is cold and rainy outside where I am in lala land :biggrin:

Greg Guimond

12-29-2013, 05:09 PM

Ok so I'm lookin at Matty and Jay's 16 and how they sit at rest. I can now say with certainty that both Ghost and woobs are downright looney if they think that removing 600lbs of extra weight would only hike the hull higher by 1" at 65mph. Not possible when you look at the picture of the two I/Os side by side albeit at rest. Now before I head out to check out Llewyn Davis I'm taking another strake bake fly bye.

A. 55er strakes are out of the water completely at 65mph
B. They would just be touching (at 65mph) if they were 49" from the transom
C. The faster a hull goes (same prop) the less of that hull stays in the water as you air it out and find the sweet spot
D. Center of Gravity would not be an issue as the wacker is further back (albeit lighter) and the CofG on the 16's is at 75" or 38%
E. Angle of Attack would go to the wacker. Trim is infinite and carrying the bow is of no issue once correctly propped to do so. That is a fact using 1976, 1996, or 2013 data

Question - Would 10mph of extra speed to 75mph and 600lbs (per Matty) less weight toward the transom mean that only 2' of hull would be in the water and not 4' ?

Answer - :outtahere::outtahere:

woobs

12-29-2013, 05:50 PM

Call me "looney" if you like. Feel better?

I'm done with this for a while...........

Ghost

12-29-2013, 06:04 PM

Ok so I'm lookin at Matty and Jay's 16 and how they sit at rest. I can now say with certainty that both Ghost and woobs are downright looney if they think that removing 500lbs of extra weight would only hike the hull higher by 1" at 65mph. Not possible when you look at the picture of the two I/Os side by side albeit at rest.

You can say it with certainty because you don't understand the forces that lift the boat at speed and at rest, and how they are different. :)

Take a super strong 16, laden with a very heavy, infinite hp motor that's so heavy that only 6 inches of the boat are above water. So, it's drawing what, say, 3 feet at rest? It probably weighs what, 4500 pounds or more? Now, run it faster and faster until it draws only 2 inches of water.

Then, take out the heavy motor and put on an infinite hp outboard that weighs 300 lbs. Now, at rest, the boat draws nine inches of water. So, it rides 27 inches higher at rest. Run it up to the same speed as before, will it draw 27 inches less at that speed? Or even 13 inches less? Or even 6 inches less? Of course not--it'd be hovering above the water. It was only drawing two inches at speed to begin with.

But your logic would have it up there anyway. Nothing more fun than physics in LaLaLand. :)

jl1962

12-29-2013, 06:34 PM

Greg Guimond

12-29-2013, 07:51 PM

Biscayne Bay is a large area. We have zero proof at this point, absolutely zero, and in the 49 years since Walin supposedly did it no one else has even come close with proof.... 49 years....... :umbrella:

I 100% agree with you that we have no proof. That is why it's Winter banter. The only proof is if one could find Osiris Perez and so far no go. That said, you are a bit confused. It is not 49 years. Dr. Lou Benz said he did it in 1996 so that is 17 years friend since it was claimed to be done in Gerry Walins hull.

Are you using the "new" math - 17=49

Greg Guimond

12-29-2013, 07:56 PM

Call me "looney" if you like. Feel better? I'm done with this for a while...........

No worries, and the looney reference was to both you and Ghost and all in good fun. I appreciate your position but I just don't agree with removing 600lbs and only gaining 1" in waterline at 65mph. I'm pretty sure you don't either if you think about it. The math just does not support your logic.

Ed Donnelly

12-29-2013, 08:16 PM

Ghost

12-29-2013, 08:27 PM

No worries, and the looney reference was to both you and Ghost and all in good fun. I appreciate you position but I just don't agree with removing 600lbs and only gaining 1" in waterline at 65mph. I'm pretty sure you don't either if you think about it. The math just does not support your logic.

This is laughable. Did you read my example case above? You are basing you analysis on the boats at rest. The MATH of how the boats differ in waterline height at speed is based on different forces.

Did you try to understand the example I gave? It shows the absurdity of your logic, unless you expect a sixteen at speed would run several inches above the water at 65, If you could get the weight down a ways. Doesn't work that way.

Greg Guimond

12-29-2013, 08:34 PM

I honestly mean no disrespect Ghost but I can't really follow anything you have said below ..............

You can say it with certainty because you don't understand the forces that lift the boat at speed and at rest, and how they are different. :)

Actually I understand the forces pretty well. I engaged Jim Russell when I was putting together my build. He is pretty much "the man".

Take a super strong 16, laden with a very heavy, infinite hp motor that's so heavy that only 6 inches of the boat are above water. So, it's drawing what, say, 3 feet at rest? It probably weighs what, 4500 pounds or more? Now, run it faster and faster until it draws only 2 inches of water.

Buizilla weighed his 1996 OB and it was (I think) 3000 pounds on the money without the trailer but filled with 65 gallons of fuel, rigged to the hilt and with a heavy TRP wacker. How are you getting to 4500lbs with a 25 gallon tank full of fuel and a V8 mated to an AQ? There is no way that V8+AQ is drawing 36" at rest.

Then, take out the heavy motor and put on an infinite hp outboard that weighs 300 lbs. Now, at rest, the boat draws nine inches of water.

Where are you getting 9" of drawt? A 16 Donzi at rest draws 14". That 14" will increase based on the weight in the stern. With a 300lb O/B ( it is really 258) it would go a touch deeper. Then if you have a light I/O like Jays, a little deeper. Then if you have a V8 a bit deeper stiil. It is NEVER drawing 3 feet at rest.

You are saying that swapping out the car motor and I/O at 1500lbs stand alone static weight with a 300lb wacker and the boat elevates at rest by 27"? 2+ feet? Huh?

Where the heck did you come up with 27"? I actually can't go any further with this because I have lost the logic. I actually like that you take a stab at it but not really following the pieces and parts that you use. I may be wrong, but doubt it.

So, it rides 27 inches higher at rest. Run it up to the same speed as before, will it draw 27 inches less at that speed? Or even 13 inches less? Or even 6 inches less? Of course not--it'd be hovering above the water. It was only drawing two inches at speed to begin with.

First off, it never sat at 27" deeper. Explain that and then I can comment on the rest. Now to take the story forward, at 65mph, look at Bill's picture

But your logic would have it up there anyway. Nothing more fun than physics in LaLaLand. :)

Greg Guimond

12-29-2013, 08:38 PM

So my son asks "Dad, do you know how to fit an elephant on the subway? It's easy, just take the "S" out of SUB and the "F" out of WAY."

To which I said "Wait, there's no F in Way"

Exactly, he said.........

Great thread but until Greg can get The Mule or Surface Tension (both w/ all mod cons) to duplicate this feat, then I remain at ZERO. :)

How was the movie?

Movie was very good. I will say that if you get a chance to watch the documentary on the way the music and the film was put together with T Bone and the Coens, that piece is pretty special. Having lived in NYC for 20+ years there is lot of musical history and the folks doing the playing are pretty dang amazing. Check it out. :yes:

Greg Guimond

12-29-2013, 08:42 PM

Buizilla weighed his 1996 OB and it was (I think) 3000 pounds on the money without the trailer but filled with 65 gallons of fuel, rigged to the hilt and with a heavy TRP wacker.

uhhh. no I didn't, I said it weighed 3000# on the trailer, full fluff

Oops, sorry. That's why I said (I think) So does that mean it was 3000 pounds, including the 625lb alum trailer and full of fuel?

Greg Guimond

12-29-2013, 08:47 PM

This is laughable. Did you read my example case above? You are basing you analysis on the boats at rest. The MATH of how the boats differ in waterline height at speed is based on different forces.

Did you try to understand the example I gave? It shows the absurdity of your logic, unless you expect a sixteen at speed would run several inches above the water at 65, If you could get the weight down a ways. Doesn't work that way.

You might want to review the posts ;) I tried to understand it but actually couldn't ........... at all.

Greg Guimond

12-29-2013, 09:10 PM

84mph in a 64-68 Ski Sporter 16 with 55s is still a 50% proposition for me. Not willing to give up on Dr Lou (could he just lie outright?) just yet based on the prior posts. Matty's wheel info for #452 will be telling to me.

That said, the importance of the 21s versus the 55s certainly plays a role but that has diminished in my mind. I think that properly rigged and propped, that a 16 could exist on 2 feet of azz end hull. Not a cakewalk for sure, but when I run my pad bottom I am on 8 or 9" of back end with (surprisingly) a ton of trim. YES apples and oranges with the pad, but my gut tells me that throwing out the 75mph (actually 77 best case) speed that the long straked 16 OB clocked could be a bit harsh. We have 49s at 65mph. I don't know exactly what 10mph faster does hydrodynamically but it has an effect for sure. Does it clear 21s? Not 100% known at 2" or even 1" higher waterline and 10mph faster speeds. Again, faster means less wetted surface with a wacker that has unlimited X and unlimited trim. Still a possible amount of keel to run on from my experience running them factory stock and then with a pad, thus 50% in my book.

Greg Guimond

12-29-2013, 10:51 PM

There are numerous idle zones and few WFO zones north of Dodge Island to Sunny Isles to air it out but in select areas.... in '96 it could have been done in certain area's but I am pretty adamant on staying in MO on this without unequivocal proof it was done... we have zero proof at this point, absolutely zero, and in the 49 years since Walin supposedly did it no one else has even come close with proof.... 49 years....... :umbrella:

Jim, you a missing several chapters. Has the sun down there gotcha? Gerry Walin is dead. He died in late 1976. No one ever said that Gerry Walin clocked 84mph. Gerry Walin did not say it because he is dead, and Dr. Lou Benz who bought the boat in 1976 did not say that Gerry said it. Capiche? Ok, next.

Dr. Lou Benz (dormant donzi.net board member) said he did 84mph in the 1965 OB#1 hull on a day in 1996. He said it had an Evinrude Super Strangler race motor pushing it. It sounds like your waters are a bit lighter then mine, so there is room to air it out as you say. There is room in certain areas so that makes the length needed for the run probable. Btw, dead flat water is not needed, the hull appreciates a small chop, just ask me. Capiche? Ok, next.

Dr. Lou told me he made this pass with Osiris Perez watching him. He told me that in 2012, and then again this year in 2013. He said he did the pass in 1996, 17 years ago, but he told me the information, again, this year after I resurfaced this thread. He made a point when he told me this year, that it was marked on Garmin, and that he remembered it like it was yesterday. Capiche? Ok, next.

If you want to call Dr. Lou Benz a liar, that is aok with me. As I have said that is an individual decision and I could give a rats arse what you decide. But, you need to get your facts straight first. Capiche good buddy? :)

Greg Guimond

12-29-2013, 11:39 PM

for the record here is the boat that was featured on the powerboat magazine cover. you can see with the woman sitting in the bucket seat facing backwards were the confusion of an 18 with lounge seating came from. hull number 18-390

Thanks Matty. A little picture update ...........

jl1962

12-30-2013, 06:07 AM

Movie was very good. I will say that if you get a chance to watch the documentary on the way the music and the film was put together with T Bone and the Coens, that piece is pretty special. Having lived in NYC for 20+ years there is lot of musical history and the folks doing the playing are pretty dang amazing. Check it out. :yes:

It's on our list. "O Brother", and "Raising Arizona" are my favorite Coen Bros movies. I saw T-Bone play with Squeeze and Elvis Costello many years ago in Chicago, he was great.

This is a terrific thread and I love the discovery and the reverse engineering, but if 84 can't be/hasn't been done with modern engines, steering, bottom design, it seems a real stretch that it could have been attained with 50 year old technology. OK, maybe I'm at 1%!

Now get one of your boats done (I think you're just using this thread to distract you ;) ) and get an old outboard with the baseball bat exhaust (an o/b guy like you should have both vintage and modern in your quiver) and bring it all to LG in the Spring!

:)

Greg Guimond

12-30-2013, 07:11 AM

I suspect that they are releasing a soundtrack to the Davis movie which would be awesome. The thing that was amazing was who they found to play the lead. Great actor and great musician.

mattyboy

12-30-2013, 07:48 AM

Greg Guimond

12-30-2013, 08:00 AM

Is that picture on the left an actual 16 Ski Sporter?

mattyboy

12-30-2013, 08:28 AM

looks like a clone splash same hull with a different deck layout to get the 10% different status. so anyone have an estimate on how heavy a merc setup is drive and transom housing? 100- 125 lbs??

Greg Guimond

12-30-2013, 08:32 AM

mattyboy

12-30-2013, 08:48 AM

Matty, are you saying this specific to a short straked 55er Ski Sporter 16 or ANY 16 Classic?

I would imagine this applies to any small boat. I would also think that a long strake 16 would do this even more so as the azz end sits higher to begin with

Greg Guimond

12-30-2013, 08:53 AM

removing 600lbs of weight from the back of a 16 type hull will drive the nose down look at this 16 type hull with just the outdrive no engine the hook is above the water but look how much of the front is now wet then look at mine at the dock how high my nose is. sorry the balance with 258 on the back is not enough to carry the front not no way not no how.

I don't think you are factoring in where the Center of Gravity is on a Donzi 16. It is at 38% naked.

Greg Guimond

12-30-2013, 09:02 AM

I didn't call anyone a LIAR.... Capiche?

until such postulated facts, as you and Lou stated, are proven, then it becaomes TRUTH, Capiche?

until then, everything is RUMOR and CONJECTURE and GUESSING, and up until now pretty ridiculous unproven permutations over 49 years worth of babbling

PRETTY SURE MY FACTS ARE STRAIGHT, I knew when Gary died, suicide right? okayyyyy

what was Gary's speed in 1965 again? I think i've asked that

with that said, i'm outa this one

Facts? No one is saying it is fact. There are no pics. It is Dr. Lou's claim. What does Gerry Walin's speed in 1965 have to do with anything? He set several world records in 1965 in various boats. The only thing being chatted about here is Dr. Lou's claim of 84mph that occurred in 1996 in Miami. 49 years? I must be missing something. Don't be so sensitive btw, it's only a chat board. Cya.

Greg Guimond

12-30-2013, 09:15 AM

I would imagine this applies to any small boat. I would also think that a long strake 16 would do this even more so as the azz end sits higher to begin with

I hear you but not sure I follow. My first 16 OB had a 1978 Evinrude 235 mounted directly to the transom. That motor weighs 380lbs. It carried the bow of that 16 Baby no problem with 21's and did not drive the nose down?

mattyboy

12-30-2013, 09:17 AM

Greg

please stop putting words in my mouth , quote me any time but please don't edited the quotes I didn't say 600lbs in that post I said weight.

we don't run them naked so where is the cog on a fitted rigged fueled one for running with an avg American driver?

I am looking for pictures I have Of John Benkcozy's baby 16 and mine side by side I looked like I was sinking from the stern next to his.

Greg Guimond

12-30-2013, 09:29 AM

removing weight from the back of a 16 type hull will drive the nose down look at this 16 type hull with just the outdrive no engine the hook is above the water but look how much of the front is now wet then look at mine at the dock how high my nose is. sorry the balance with 258 on the back is not enough to carry the front not no way not no how.

I think we are comparing what would happen with a 258lb Super Strangler on the back of a 1964-1968 Ski Sporter as opposed to a much heavier I/O boat. I think you said that an I/O boat would be between 550 and 750 pounds heavier than the wacker. I decided to use 600lbs, sorry for that but it seemed reasonable. You are saying that the balance of a 16 with only 258lbs on the back WILL NOT "carry the front". I'm saying I disagree, 258lbs is enough. My first hand experience with 380lbs was also enough to carry the front.

The Center of Gravity at 38% naked tells you how the bow would be carried at birth, it is just for overall perspective.

mattyboy

12-30-2013, 09:33 AM

I hear you but not sure I follow. My first 16 OB had a 1978 Evinrude 235 mounted directly to the transom. That motor weighs 380lbs. It carried the bow of that 16 Baby no problem with 21's and did not drive the nose down?

122 lbs heavier than lou's SS so yes I would imagine the balance on your baby was different from lou's 16 what speeds did you see with the 235hp?

I think you had mentioned when the SS blow up on Lou he went to a rude 135 hp what speeds do we think he ran with that motor?

Greg Guimond

12-30-2013, 10:29 AM

122 lbs heavier than lou's SS so yes I would imagine the balance on your baby was different from lou's 16 what speeds did you see with the 235hp? I think you had mentioned when the SS blow up on Lou he went to a rude 135 hp what speeds do we think he ran with that motor?

Yes, my 1978 Evinrude 235 was 122lbs heavier than the 1975 Evinrude Super Strangler Race motor that Dr. Lou had on the back of the 1965 16. I can tell you from extensive experience that 122lbs would have inches of effect on the 16s balance. Not even a foot but inches. Also, being 122lbs lighter would in no way effect the ability to carry the bow, zero. My 235 did 60-61. Lou never went to an Evinrude 135 after the Super Strangler blew up after his claimed 1996 run of 84mph in Miami. The Donzi factory however did rig there production 16 OB Baby's with Evinrude 135 fishing motors when they were shipping them in 1972.

mattyboy

12-30-2013, 11:01 AM

The next year, 1973 Evinrude introduced the Starfire 135hp model. This upgraded 135 ran from 1973 to 1976 and those years align with the motor Dr Lou said was on the 1965 16 OB Baby when he bought it from Gerry Walin in 1976.

?????????????????????????????????????????????????

with 235 hp you ran 60-61???????????????

and that's the ball game!

finute!

Greg Guimond

12-30-2013, 11:24 AM

Don't jump the gun yet. Most of the fun is in the journey. Not sure how many race wackers you have been around Matty but there is just a touch of difference between a race motor and a fishin motor. Just a touch, but I digress and that'll come later. ;) And you might also want to consider that the 1967 #452 hull is running 68mph with a 205hp fishin motor. How can he run 68mph with less horsepower than I had? Answer please?

Sidebar - what lower unit did Rootsy run on his 16 Ski Sporter that did 80mph?

Greg Guimond

12-30-2013, 11:56 AM

Back to the strake bake for a vacation re-visit. I took another look at Bill's 16 picture where he is running 65mph. He has 55s. His inner lifting strakes terminate 55" from the transom just like woobs strakes do on his 16 that he evidently measured himself. I had said earlier that I thought there was still more room in the photo before the strakes would be touching water based on the pic and there is. I laid it out to scale with a little clear ruler thingy that our youngest has for her school backpack. She and I did a little math experiment and scaled the 55s. Then we used that scale to lay over the "open space" in Bills pics. That scale indicates that IF the inner strakes on his 16 would have been 9" longer only at that point would they even be touching water.

So, at 65mph with 600lbs of extra stern weight iron, you could have inner strakes that terminated 46" from the transom before they touch water and offered any lift.

21ers - '70 - '78 Baby 16 OB inner strakes terminate 21" from the transom at rest
46ers - '64 - '68 Ski Sporter 16 (running 65mph)
55ers - '64 - '68 Ski Sporter 16 inner strakes terminate 55" from the transom at rest

Hmmmmmm

Greg Guimond

12-30-2013, 12:43 PM

Greg Guimond

12-30-2013, 10:07 PM

I'm ready to put a stake in the strake bake. Here are two photos of 16s. One one the left has a V8 I/O, probably similar in weight to Bill's. The other has a 175 Evinrude mounted to the transom. The extra 600lbs of weight of the I/O at rest looks to easily draw about 4-5" more water in the pic. Ghost was thinking that at 65mph the O/B boat would be 1" higher in the water. He has no chance based on these photos at rest. It would easily be 3" higher for the wacker and maybe 4". If the boat is running at 3"-4" higher at speed that means less strake in the water and less wetted surface (or drag) when running the Mercury 225 at 75mph.

Bill's inner strakes, which if they were 46" from the transom would be out of the drink at 65mph set the bar for me. With the lighter O/B on the back, the hull would raise easily 3" at the identical speed of 65mph. Now less inner strake is in the water. Then, you add 10mph in speed and EVEN LESS inner strake is in the water. At 75mph with a Mercury 225 on the back, the 21s are barely touching water. Maybe a touch here and there, but they are really offering no "lift" and thus no speed gain.

Speed plays a very large role with the inner strakes. If you are doing 45 they are very much in play. At 75mph, they are not helping gain more speed. You are running a 5-10 degree attack angle and you are aired out.

Greg Guimond

12-30-2013, 10:15 PM

At slow speeds the inner strakes played a role, no doubt. At high speeds, they are out of play. Here are two very early 16 Ski Sporter hulls...............

Greg Guimond

12-30-2013, 10:20 PM

.
.
This picture gives a perspective of attack angle at mid range cruise speeds. Notice the angle is at 5 degrees. As speed climbs, attack angle tends to increase. Fully aired out at 65mph it might grow to 8 or 10 degrees.

Greg Guimond

12-30-2013, 10:41 PM

1965 Ski Sporter boat weight .......... check
1996 GPS technology ......................check
Propeller technology .......................check

Possible 84mph? ............ priceless :bighug:

And so we update the puzzle pieces..............

1965 Ski Sporter boat weight "naked" with empty tank and brightwork - 1,000lbs (I still think it is 900lbs) .............................................check
1965 Ski Sporter total weight with 25 gallon tank full, Super Strangler O/B, a driver, and all the bits & pieces - 1,600lbs (per Matty) ........check
1965 Ski Sporter 55ers as compared to 1975 16 OB Baby 21 inner strakes considering weight difference - no effect ..............................check
1975 race propeller technology as compared to 2005 - equal at best .................................................. ...........................................check
1996 Garmin GPS technology in Miami and GPS reading quality in general .................................................. ..............................check

Walking parched through the Sahara, in search of water and 84mph ............. priceless :smile:

Greg Guimond

12-30-2013, 11:07 PM

And a cameo appearance from Dr. Lou ..............

There were several '65 and '66 outboards sold. I have a "stinkin" 1965 16 outboard that was sold to Gerry Walin by Donzi. He used it as a test mule for the Starflite and it still has the motor on it. I know of another 1965 "stinkin" 16 outboard that was used by Mercury for testing in 1966 on Lake X and was destroyed while in tow in Lakeland Florida. Donzi also built another "stinkin" 1965 19 foot outboard and it was built for the great Jerry Langer who drove it to first place at the 1965 Sam Griffith Memorial Race in Miami. I believe that Allan Brown is a treasure of Donzi history and a wonderful part of this registry. I am only sorry that my boat offends him so.

Ghost

12-31-2013, 12:07 AM

I'm ready to put a stake in the strake bake. Here are two photos of 16s. One one the left has a V8 I/O, probably similar in weight to Bill's. The other has a 175 Evinrude mounted to the transom. The extra 600lbs of weight of the I/O at rest looks to easily draw about 4-5" more water in the pic. Ghost was thinking that at 65mph the O/B boat would be 1" higher in the water. He has no chance based on these photos at rest. It would easily be 3" higher for the wacker and maybe 4".

What is the difference in waterline height at the transom of those two boats, at rest? Sounds like you are saying it is 4 to 5 inches, just confirm. So it is certain what you are saying. 5 inches looks okay to me, based on the pictures, just want to confirm.

And what is your predicted difference in transom waterline height at 65 mph? Sounds like you are claiming it would be 3 to 4 inches, again, please just confirm.

Then, explain the relationship of the predicted number at speed to the observed number at rest. Explain how you get the latter based on the former. What's the logic? What's the math?

Greg Guimond

12-31-2013, 08:44 AM

my inner strakes ends are approx. 58" inboard of the transom..definately NOT 55"

No picture no proof :wink:

Greg Guimond

12-31-2013, 08:45 AM

What is the difference in waterline height at the transom of those two boats, at rest? Sounds like you are saying it is 4 to 5 inches, just confirm. So it is certain what you are saying. 5 inches looks okay to me, based on the pictures, just want to confirm.

And what is your predicted difference in transom waterline height at 65 mph? Sounds like you are claiming it would be 3 to 4 inches, again, please just confirm.

Then, explain the relationship of the predicted number at speed to the observed number at rest. Explain how you get the latter based on the former. What's the logic? What's the math?

Do I have to? I'm on vacation ;)

Greg Guimond

12-31-2013, 08:51 AM

Like my Mom use to say
"It's all fun and games til someone loses an eye

Too bad Lou didn't document, take pictures and swore on the Bible or Torah
It's all here say now
just like my over a 100 in my 16' I saw the radar gun but didn't take a pic of it
So it's just here say ..Ed

I'm still blown away Ed that you did triple digits in a 16. That must have scared the livin fugh out of you. Truly amazing work. Yeah, the Doc should have taken a picture. Oh well, I tend to believe people. ;)

Greg Guimond

12-31-2013, 10:26 AM

What is the difference in waterline height at the transom of those two boats, at rest? Sounds like you are saying it is 4 to 5 inches, just confirm. So it is certain what you are saying. 5 inches looks okay to me, based on the pictures, just want to confirm.
I am confirming that the red 16 with the 351/250 I/O combo is sitting lower in the water than the HH 16 with the '80s vintage Evinrude 175 O/B. I took a closer look at the photos and I now believe that the I/O boat is sitting 6" lower. I'm happy to use 6". I'm also happy to say that this would also apply to Bill's yellow 16 as I think the weight could be similar to the red 16.

And what is your predicted difference in transom waterline height at 65 mph? Sounds like you are claiming it would be 3 to 4 inches, again, please just confirm.
Transom waterline was not my focus here. It's just a static starting point. My comments were around how much of the hulls entire wetted running surface would be elevated at 65mph. I am saying that the lighter Evinrude 175 O/B 16 would be 3" higher at the identical 65mph speed. This is because the extra 600lbs of the I/Os weight is behind the hulls 38% CoG. So to confirm, yes, wetted surface would be 3" higher at the same speed and attack angle with the wacker. There would be 3" less wetted running plank to create drag.

Then, explain the relationship of the predicted number at speed to the observed number at rest. Explain how you get the latter based on the former. What's the logic? What's the math?
I'm like BUIZILLA and his strakes, too lazy to go to the warehouse where the CRAY is for the precise math. The short answer though is hydrodynamics and my owning and running 16 OB Baby's for a decade, with many different wackers on the back. There is a direct relationship to speed and wetted surface. Even if you are the heavy I/O boat and start static 6" deeper, once you get to about 45mph you will begin to shed wetted surface as you move the speeds higher. This is why the inner lifting strakes play a role at lower speeds, but loose some of that benefit as the speeds increase, until they are out of the water entirely. You have to remember that attack angle tends to increase slightly over the speed range assuming you are propped correctly which is important. But if you are, your attack angle might be 5 degrees at 50mph, but then climb say to 7 degrees at 65mph, and 9 or 10 degrees at 75mph as you tap the trim to find the sweet spot. At that point in a 16 you are riding on say 2' of hull length and the same 2' of the outer lifting strakes. If you can't drive worth a chit then you may never get there, but that is another thread. These 16's are about 12" deep from the outer waterline chine to the bottom of the round keel, but what you are really running on at say 65mph is probably only the V depth triangle of the outer lifting strakes (48" apart) and the bottom of the keel. I don't know what that exactly is but it is obviously less than 12" of depth.

Ok, second cup of coffee. I'll take the bait :jester: My thoughts above.

Greg Guimond

12-31-2013, 10:47 AM

One other note. There is always a lot of talk on this board about 16's "running out of hull" such that they can't go fast and are uncontrollable. Both Rootsy and Parnell proved that 80mph is well within reach with proper setup. This is part of the reason I am still 50% of Dr. Lou clocking 84mph with a wacker. You have two guys that clocked 80mph with car motors and another guy that clocked 75mph with a wacker. That shows the hull can get there, provided the driver can bring it. :yes:

Gotta go watch the game now ......... :outtahere:

mattyboy

12-31-2013, 10:50 AM

again apples to oranges

how can you assume a 175 rude is going to push a 16 to 65??? you couldn't do that with your 235 rude??????.

someone is going to have to explain how a 235 rude can only reach 61 but a 225 merc can hit 74?? sounds like newer technology is faster than 1970s technology on the same hull???

now we have pics of a sutphen with a pad??

so with 235 hp you get 61 then let's add 1 mph for the weight difference of 122 lbs over lou's ss 62mph

then let's say lou had no shifting and had the racing lower for another 10 mph that is 72 mph now how are we going to make up that 12 mph to get to 84

I know Lou had his gps set to KPH

Greg Guimond

12-31-2013, 10:58 AM

Do you have a lot of experience with wackers? Here is a quicky but gotta go

again apples to oranges

how can you assume a 175 rude is going to push a 16 to 65??? you couldn't do that with your 235 rude??????.
You said that #452 has a worked 175 that did 68mph. I did not say that, you did.

someone is going to have to explain how a 235 rude can only reach 61 but a 225 merc can hit 74?? sounds like newer technology is faster than 1970s technology on the same hull???
That will be easy but no time now

now we have pics of a sutphen with a pad??
The Sutphen picture was just to show the lack of inner lifting strakes. It is competitive with 5 other boats that have much longer inners

so with 235 hp you get 61 then let's add 1 mph for the weight difference of 122 lbs over lou's ss 62mph. then let's say lou had no shifting and had the racing lower for another 10 mph that is 72 mph now how are we going to make up that 12 mph to get to 84
I don't understand any of what you have here

I know Lou had his gps set to KPH

Ghost

12-31-2013, 12:03 PM

Ok, second cup of coffee. I'll take the bait :jester: My thoughts above.

LOL, good God man, how about you stop rambling about other things and answer the question? Earlier in the thread you said Woobs and I were "looney" about the ob only running an inch higher than the v8. Your basis for this was that the ob sits 4 to 5 (now 6, fine, happy to use your number) inches higher at the transom. Since you are able to base your claim that the ob boat will run 3 inches higher at 65 based on the 6" difference at rest, what is the relationship of one to the other? Other than that you just made it up? And stop blathering about a Cray. I'm not asking for a precise calculation, just a rationale with more substance than "because you think so." WHY would 6 inches of displacement difference at rest translate to half that height difference at 65? (If it were 8 at rest, would you estimate 4 at speed? if it were 10 at rest, would you then estimate 5? Understand that if you say no, it stays at 3" regardless of what happens at rest, then you are not basing the number at speed on the number at rest.)

And by by the way, how did your estimation logic change so much in the last day? (Before, 4 to 5 inches of difference at rest meant 3 to 4 inches at 65 mph. Now, 6 inches of difference at rest means 3 inches at 65 mph. You have gone from a range of 60-100% ratios, to now claiming it's 50% ratio. This is a HUGE change if one is actually using any sort of logic to take an observed number at rest to estimate the number at 65. Of course, if you're just making numbers up, as I contend, it's only an inch or two, whatever that means.)

So again, cut the bs comments about a Cray (nobody asked for "precise" math, just the rough logic) and instead just explain HOW THE NUMBER SEEN AT REST factors into your estimate of height difference at 65 mph. It is worth noting that your third paragraph earlier doesn't relate the at-rest and at-speed numbers at all, it actually makes a logical case for there being ZERO height difference at speed, as it only describes a relationship between speed and height. Seriously, read your own words. Not only did you NOT give any logic relating the height difference at 65 to the height difference at rest, what you did give was an argument why the difference would be ZERO at 65, regardless of the difference at rest. If you don't see this now, read your own words again.

mattyboy

12-31-2013, 12:33 PM

That's half the problem with this thread there is some much stuff thrown out to see what sticks

I was referring to your post 780 where you pictured a 175 rude on an austraillan 16 then state 65 mph

when I refer to 452 i use hull 452 or the stated hp of the motor 200 hp not what the motor started as.

the last statement I made was that you mentioned 100 lbs would be a 1 mph gain so take your 235 hp 61 baby add the 1 mph gain from the difference in weight of the SS and the 235 of 122 lbs

then if i am correct from what i have read on other forums on the fact that the slippery super fast lower of the SS came with only fwd so lou couldn't shift I will add a generous 10 mph gain bringing you do 72 mph 12 mph short of lou's number. so let's add a mph for every increase of 20 hp ( which may be accurate in the first few jumps then not so much) 100 hp to 335 a gain of 5 mph that leaves you at 77 mph still 7 mph off the pace

Ghost

12-31-2013, 12:35 PM

Another strake bake factoid. YES woobs a bit of apples to oranges for sure but ..................

The boat below is one of the (6) fastest rough water deep Vs in the world with an O/B on the back end. See any long running inner strakes? The other 5 boats it competes with range in speed from 84mph to 102mph.

I'm in complete agreement that longer inner strakes help in acceleration and at slower cruise speeds. However, in this thread I'm still not sure they are even in the water when you combine the relative lightness of an O/B, the infinite trim of an O/B, and the speed of 75mph that was achieved with the 16 O/B Baby with the 225 Merc on youtube.

Sidebar--not sure what this should make anyone conclude, given how different a pa bottom is from a round keel. A round keel provides VERY little stability to oppose roll compared to a pad, and a pad may well decrease wetted surface like inner strakes would, by giving a pronounced transition in the direction of water that tries to make its way outward on the hull. Or not, depending on the geometry at speed, that one feels like it could go either way. I think the pic may be misleading in that it almost certainly can't be showing steady-state, the boat has surged up out of the water or has something that acts like the most effective inner strakes ever. This is great for showing us the bottom, but not useful for shedding light on what the boat does hydrodynamically when up above 80.

Also, it sounds like the confusion continues over strakes, speed, acceleration, etc. The part that Greg is right about is that for boats that have exceeded the speed where their inner strakes are wet, those dry inner strakes don't affect the top end. Yes, no doubt (aside from aerodynamic effects, whatever, but that should be a tiny fraction of the other things we are discussing.). As such, their strakes only matter at lower speeds where they are wet, and likely do help with acceleration.

But this truism in no way should suggest that inner strakes would not improve the top speed if they went further aft to where they were deflecting water. Greg is wrong to the extent he says inner strakes inherently help acceleration but not top speed. Top speed is a limit of acceleration. Yes, strakes that are too short to matter don't help top speed, but that does NOT mean those strakes would not increase top speed if they weren't too short to matter.

Greg Guimond

12-31-2013, 03:41 PM

So again, cut the bs comments about a Cray (nobody asked for "precise" math, just the rough logic) and instead just explain HOW THE NUMBER SEEN AT REST factors into your estimate of height difference at 65 mph. regardless of the difference at rest.

Sure thing Ghost, here is the simple version for you. If the 16 is 600lbs heavier and sits 6" lower at rest, it will sit 6" lower under way until about 50-55mph. At 55mph and above the hydrodynamics change and the depth relationship is altered. It continues to adjust (proportionally) as the speeds increase. The light wacker will have even more of an advantage above 55mph. I can't remember exactly but I believe the math was about 1" less wetted surface for each mph gained above 55mph to start for a wacker 16.

I'm not sure I can make it much simpler for you but would love to hear how you look at it :doh:

Greg Guimond

12-31-2013, 03:51 PM

That's half the problem with this thread there is some much stuff thrown out to see what sticks. I was referring to your post 780 where you pictured a 175 rude on an austraillan 16 then state 65 mph. when I refer to 452 i use hull 452 or the stated hp of the motor 200 hp not what the motor started as.
the last statement I made was that you mentioned 100 lbs would be a 1 mph gain so take your 235 hp 61 baby add the 1 mph gain from the difference in weight of the SS and the 235 of 122 lbs. then if i am correct from what i have read on other forums on the fact that the slippery super fast lower of the SS came with only fwd so lou couldn't shift I will add a generous 10 mph gain bringing you do 72 mph 12 mph short of lou's number. so let's add a mph for every increase of 20 hp ( which may be accurate in the first few jumps then not so much) 100 hp to 335 a gain of 5 mph that leaves you at 77 mph still 7 mph off the pace

Matty, let's then use 1967 Hull #452. You said that the current owner claims it does 68mph with a warmed over Evinrude 175 that is putting out about 205hp. Do you agree with him? Lets just start with that question and then I will answer all the rest easily.

Do you agree with 68 mph?

Greg Guimond

12-31-2013, 04:48 PM

The part that Greg is right about is that for boats that have exceeded the speed where their inner strakes are wet, those dry inner strakes don't affect the top end. Yes, no doubt. As such, their strakes only matter at lower speeds where they are wet, and likely do help with acceleration.

But this truism in no way should suggest that inner strakes would not improve the top speed if they went further aft to where they were deflecting water. Greg is wrong to the extent he says inner strakes inherently help acceleration but not top speed. Top speed is a limit of acceleration. Yes, strakes that are too short to matter don't help top speed, but that does NOT mean those strakes would not increase top speed if they weren't too short to matter.

I don't believe I ever said that. My "inner" lifting strake comments were in the context of 55s and 21s only and if you HAD to have 21s to achieve the Dr Lou claim of 84. The answer IMO is that we have shown that you don't need the 21s to achieve even 75mph. At 75mph they are probably JUST touching the water because of the lighter wacker weight.

Ghost

12-31-2013, 05:21 PM

I don't believe I ever said that. My "inner" lifting strake comments were in the context of 55s and 21s only and if you HAD to have 21s to achieve the Dr Lou claim of 84. The answer IMO is that we have shown that you don't need the 21s to achieve even 75mph. At 75mph they are probably JUST touching the water because of the lighter wacker weight.

Actually, if you look, Post 572 makes it clear that your context claim in incorrect (at least there, which is why I mentioned it again now where it seemed ambiguous). In 572, it is clear that the true relationship of acceleration to top speed has been confused. After all there is no going faster without acceleration. Top speed occurs at the limit of increases in acceleration. One doesn't reach top speed and then go "faster." One keeps going faster until one cannot accelerate further, the point of top speed. Fwiw.

Greg Guimond

12-31-2013, 05:39 PM

I'm cool with that but the focus is on how important 55s and 21s are. I'm saying that 55s are not in play at 65mph in an I/O and 21s are not in play at 75mph on an O/B powered boat. I wasn't sure earlier in the thread, but now I am confident. That said I am now at 60% confidence that Dr. Lou achieved 84mph in Miami 17 years ago racing Osiris Perez.

Direct question. Do you agree that 21s are not in play at 75mph?

Ghost

12-31-2013, 05:47 PM

I'm cool with that but the focus is on how important 55s and 21s are. I'm saying that 55s are not in play at 65mph in an I/O and 21s are not in play at 75mph on an O/B powered boat?

Direct question. Do you agree that 21s are not in play at 75mph?

Fair enough, and not sure on that question Have to think on it, though my instinct is that 21s would be in play in almost any flavor of 16 at 75. But have to think more.

Ghost

12-31-2013, 05:51 PM

Greg Guimond

12-31-2013, 05:53 PM

That's fine. Let me know. If someone was good with geometry I suspect you could plot it out using an attack angle of 9/10 degrees with 48" outer strake width and a max of 38% Center of Gravity.

:band:

woobs

12-31-2013, 06:26 PM

Okay, i said I was out but... I'll try explain 1 more time...

3 boats.
All at the same speed (say 65mph)
All with the same amount of hull in the water.
All strakes are above the water level

A=No strakes, B=short inner/long outer strakes, C= long inner and outer strakes

A: Water pushes up the hull to the chine where it's adhereance is broken and the water ejected as spray (44 squares of resistance in pressurised area of hull)

B: Water adhering to the hull misses the inner strakes and is pushed to the outer strakes where it is ejected and becomes spray (38 squares of resistance in pressurused area)

C: Water adhering to the hull is caught by the inner strakes and ejected as spray.(29 squares resistance in pressurized area)

Longer inner strakes reduce drag even though they are higher than the water level. This is why a baby 16 with 21" strakes is more efficient than a Ski Sporter with 41", 55", 58" or whatever inner strake that does not reach back to the pressurized area of the hull.

You can see on the woody with NO strakes how the water adheres to the hull all the way up to the chine.
.785857858478586

Greg Guimond

12-31-2013, 06:44 PM

Welcome back woobs! You've got a lot of data up there and I am grounded with a serious cold :frown: so now I have to make my small brain work three times as hard. Hmmmmm

woobs

12-31-2013, 06:49 PM

Now to explain ride height....

Gravity does not change.
Thrust we assume to be constant
Assume both heavy boat and light boat have enough power to plane the hull.
Resistance decreases as the boat rides higher...okay so far?

Now here's the tricky part...Lift decreases with decrease in wetted surface area (resistance). Once the amount of lift is equal to gravity the boat will rise no farther (IE the hull is fully planed or aired out.)

If the hull is planed/aired out before 65mph both a heavy boat and a light boat will be at the same ride height. (unless you expect it to fly...then you need a helluva lot more power for a lifting body)

woobs

12-31-2013, 06:51 PM

Welcome back woobs! You've got a lot of data up there and I am grounded with a serious cold :frown: so now I have to make my small brain work three times as hard. Hmmmmm
It's a pretty simple concept.

Greg Guimond

12-31-2013, 07:13 PM

Another 16 OB owner with 21s.........

Look at your 16 OB boat's bottom. The inner strakes end a couple feet forward of the transom. When you are running fast with the motor trimmed out to raise the bow, you have only a smooth, convex surface on which to run. Your outer strakes are out of the water because at high speeds the lift raises you up. If you trim your bow up, then little, if any, of the inner strakes are in the water. Thus you are skimming along on a spoon.

Greg Guimond

12-31-2013, 07:28 PM

woobs

12-31-2013, 07:41 PM

woobs, what speed are you assuming that Bill is doing in his yellow 16 in that photo? It is irrelivent as long as the hull is planed....and it looks to be.

Also, in your sketch what width apart assumption are you making for the outer strakes? Also irrelivent as long as the outer strakes are in the pressurized part of the hull.

Answers in red

Ghost

12-31-2013, 07:46 PM

woobs, what speed are you assuming that Bill is doing in his yellow 16 in that photo? Also, in your sketch what width apart assumption are you making for the outer strakes?

Greg, I don't think either answer matters, at least not yet. In fact, I doubt woobs tried hard, if at all, to model the diagram on scale with a 16, with the various strake lengths and widths, etc. I think what's important, at least to start, is the CONCEPT of how the hull is affected by water flow with strakes in and out of play. Don't get lost in the specific arithmetic of the example drawings. The numbers of squares of pressurized area is probably arbitrary, except as one gets a rough idea of the RELATIVE amounts of drag/lift/etc when the strakes are in and out of play, based on the relative numbers of squares (44 vs 38 vs 29).

(Woobs, please accept my apologies if I am wrong and you've tried to make all the scales exact based on the 16 hull, I simply assumed you had not.) EDIT: looks like we responded in parallel...so, I think I have my answer. :)

Greg Guimond

12-31-2013, 07:46 PM

Answers in red

Did you use that as the basis for your sketches?

Ed Donnelly

12-31-2013, 07:49 PM

Woobs; Hang in there. You bring as much to the table as anyone....Ed

Ed Donnelly

12-31-2013, 07:51 PM

BUIZILLA; Get back in on the action. The more the merrier....Ed

woobs

12-31-2013, 08:15 PM

Drawings not to scale.
Understanding the concept is paramount. The pictured examples just prove this is what is happening on these hulls no matter what the actual math.

Thanks for the help Ghost/ED! :)
Happy New Year!

Greg Guimond

12-31-2013, 09:11 PM

Ok, happy New Year........

Okay, i said I was out but... I'll try explain 1 more time...

3 boats.
All at the same speed (say 65mph)
All with the same amount of hull in the water.
All strakes are above the water level

Just want to confirm that we are talking about car motor I/O Ski Sporters and holding off on 16's with OB power for the moment. I'll assume YES car motor

A=No strakes, B=short inner/long outer strakes, (55s) C= long inner (21s) and outer strakes

A: Water pushes up the hull to the chine where it's adhereance is broken and the water ejected as spray (44 squares of resistance in pressurised area of hull)

In a car motor boat doing 65mph I agree. That break in surface tension however is miniscule on drag overall because its the chine

B: Water adhering to the hull misses the inner strakes and is pushed to the outer strakes where it is ejected and becomes spray (38 squares of resistance in pressurused area)

You must scale here. That's why I am telling Matty that you have to start with a CoG of 38% naked. The key is "how many length inches" of the two outer lifting strakes are collided with by water off the round bottom keel. Staying with 65mph and a car motor in this particular example, no problem, but if you did not use 48" of space that would also effect things. I don't know what you used.

C: Water adhering to the hull is caught by the inner strakes and ejected as spray.(29 squares resistance in pressurized area)

At 65mph the 55s inners are not engaged. The water is breaking BEHIND the 55s as Bill's high speed picture shows clearly. Not in his cruise pic that you made your markings against. Your concept of a boat just "being at plane" does not occur in a performance hull. At plane is 30-50mph or so and maybe 5 degree attack angle. Once you climb to 65mph your hull will raise up and your attack angle will climb a bit in a non-pad bottom speed boat. Again, the example is a car motor 16 carrying 600lbs of extra weight so I'm not touching on a wacker yet.

Longer inner strakes reduce drag even though they are higher than the water level.

Generically you are correct on "inners", but in this thread with these two boats they have only miniscule relevance, even for the car motor 16s at 65mph

This is why a baby 16 with 21" strakes is more efficient than a Ski Sporter with 41", 55", 58" or whatever inner strake that does not reach back to the pressurized area of the hull.

The '70-'78 OB Baby 16's are more efficient because of the 21's at cruise speeds, I 100% agree. However, this thread is really focused on do you have to have 21s to attain 84mph or even speeds of 68, and 75 so that has to be the analysis. As a general statement irrelevant of speed, you are spot on.

.7858578586

Just Say N20

12-31-2013, 09:48 PM

I was going 40 in the second picture. That was with the 260 hp engine which weighed about 150 lbs. more than the current engine.

woobs

01-01-2014, 01:11 AM

Sorry Greg, hull hydrodynamics do not change with "car" motors vs. "wackers". These are the forces on the hull and thrust is thrust from whatever produces it.

In example A there is no break until the chine which means more wetted surface (pressure area) and more drag. So no strakes mean more wetted hull and more drag.

To understand the concept a scale is not required. Only the presence of a strake in the pressure area to eject water and therefore reduce wetted surface (and drag). The photos corroberate this. 38% is meaningless unless you are calculating the exact values of the wetted surface (that's a lot of math) and this is not an exact quantitative discussion. Either the strakes are in the pressure area or their not. In is IN and out is OUT.

You are correct, with Bills boat at 65mph, the inner strakes are not engaged in the pressure area. Therefore there is MORE drag. And it's why a Baby can do 74mph with a 225hp motor and a similar Ski Sporter can't (or at least not easily).

Of course a performance hull achieves full plane. Using your numbers it's between 30-50mph....(I'm not sure at what speed the hull is 100% at plane) and stays on full plane upward to max speed. Once at 100% plane the boat rides no higher (please see explanation of ride height). Angle of attack will increase or decrease the wetted surface and therefore effect drag. Again there is no difference for I/O or OB in terms of hull drag.

Conceptually, I am correct that the lack of inner strakes in the pressure area means more wetted surface and more drag. The pictures of both boats bear this out. The difference in hydrodynamic drag from the hull of a Ski Sporter Super Strangler and a Ski Sporter 430HP I/O when both at 100% plane, is zero.

The 21" straked hulls are more efficient through the entire range of speed. As I have shown they have less wetted surface and less drag. I don't know how much power is required to achieve speeds of 68, 75, or 84mph. I can tell you that a 21" inner straked hull will do it more easily (with less power) and probably do it more quickly than a 41", 55" or 58" inner straked hull.

As you can see, strakes serve more purpose than just providing lift when accelerating from stop to plane and helping stability in the turns. They also reduce drag on plane.

The benefit of wackers is in that they are light, which helps with acceleration and handling. Also because they are light they require less power to get on plane (and stay there) and therefore have more of their available power to devote to increasing thrust. They probably get better fuel mileage and are quite adjustable which helps with optimum set up... And in the case of your Super Strangler, it has less drag from the lower foot. But they are limited when it comes to producing HUGE power.

So, in terms of a 55" inner strake hull achieving 74mph... when looking at a (ball park) similarly powered/weighted 21" inner strake hull... NO comparisons can be made because they are just too different.

woobs

01-01-2014, 01:25 AM

I was going 40 in the second picture. That was with the 260 hp engine which weighed about 150 lbs. more than the current engine.

My purpose in using that picture was to show the entry point of the hull (at keel) in relation to the spray coming off the strake. This shows the water pressure area line on the hull moving up the hull away from the surface (The surface is where one might incorrectly assume the pressure area ends.) and ejecting from the hull at the edge of the strake...not making it up to the chine.

It does not matter that the boat was not at 100% plane to show this.

Just Say N20

01-01-2014, 01:34 AM

Woobs, you stated your position well. Someone had asked how fast the boat was running in the second picture, so I presented that info and thought it might be interesting to know the engine in the boat was both less powerful and heavier.

Ghost

01-01-2014, 01:52 AM

Sure thing Ghost, here is the simple version for you. If the 16 is 600lbs heavier and sits 6" lower at rest, it will sit 6" lower under way until about 50-55mph. At 55mph and above the hydrodynamics change and the depth relationship is altered. It continues to adjust (proportionally) as the speeds increase. The light wacker will have even more of an advantage above 55mph. I can't remember exactly but I believe the math was about 1" less wetted surface for each mph gained above 55mph to start for a wacker 16.

I'm not sure I can make it much simpler for you but would love to hear how you look at it :doh:

Greg, i think that unusually, the best place to start here is to explain that you are wrong rather than to explain what instead is right. Which, I acknowledge, is unusual. But I would ask that you bear with me as I give you two examples to challenge your thinking. First is a pair of sixteens that weigh exactly the same amount, but where one draws six inches more at the transom, due to a different center of gravity. Same weight, different COG, so how does this fit into your model of ride heights at speed? Back to this later.

Second, and more important, is an illustration of the general concept at play here. Consider a pair of identical helicopters, except one has an extra 600 pounds of weight strapped on. Both have skids that ride on springs, such that the lighter one is 6 inches higher at rest, due to the compression of the springs. Flying forward, at 50 mph and run angle X, it would be absurd to predict that the lighter one would be at 6 inches more altitude than the other, or 3 inches, or 10 feet, or ANYTHING based on the 6 inch observation at rest, because the forces that created the 6 inches of difference at rest are so different than those in play during flight.

Well, with this, while I haven't explained the RIGHT answer, this is a useful parallel for understanding the useless basis of your wrong answer. The reality is that the forces accounting for the difference in heights at rest are RADICALLY different from the forces that determine height at speed. The boats at rest are given lift simply by displaced water, using Archimedes's Principle to give centers of buoyancy, acting in opposition to their centers of mass. Whereas the boats at speed are lifted based on the pressure applied over an area required to push water out of their way at any given speed.

I will offer some math about the right answer in time, but what's more useful first is understanding the near total disconnect between the at-rest and at-speed numbers you've tried to connect. I think you will eventually see that the real relationship to uncover is between the weight (and thus, lift and height) of the lighter boat at speed versus the weight and lift and riding height of the heavier boat at speed. Waterline height at the transom at rest has nothing to do with it. After all, look back at my first paragraph. In that example, the weights were the SAME, but the waterline heights at the transom differed by 6 inches at rest.

Greg Guimond

01-01-2014, 08:45 AM

I was going 40 in the second picture. That was with the 260 hp engine which weighed about 150 lbs. more than the current engine.

Thanks Bill, I was thinking 50mph

Greg Guimond

01-01-2014, 10:04 AM

Had it backwards......typo. Glad you agree with me and not woobs.

Greg Guimond

01-01-2014, 10:07 AM

Sorry Greg, hull hydrodynamics do not change with "car" motors vs. "wackers". These are the forces on the hull and thrust is thrust from whatever produces it.

100% agree, water flow is the same. Wetted surface is NOT. This thread is specific not generic.

In example A there is no break until the chine which means more wetted surface (pressure area) and more drag. So no strakes mean more wetted hull and more drag.

I agreed with you on Example A, but this example again does not include "no strake" performance hulls.

To understand the concept a scale is not required. Only the presence of a strake in the pressure area to eject water and therefore reduce wetted surface (and drag). The photos corroberate this. 38% is meaningless unless you are calculating the exact values of the wetted surface (that's a lot of math) and this is not an exact quantitative discussion. Either the strakes are in the pressure area or their not. In is IN and out is OUT.

I know that you are keyed in on the concept. Your concept generically is correct and yes scale would not be required in that approach. That said, this thread is not just conceptual, it is specific to Donzi 16, further specific to 55s and 21s, and then even further specific to car motors and wackers. You MUST deal with the two boats being discussed and apply the concept specifically to those two designs. The photo you used to illustrate your concept is aok. It is 100% not ok when focusing the conversation on these two hulls with 55s and 21s, adding 65mph, 75mph, and 84mph. Thus, while I am not looking to CRAY this discussion, all of the above is at the essence of how Dr. Lou's right might/might not have achieved 84mph and therefore scale is required albeit just rough scale.

You are correct, with Bills boat at 65mph, the inner strakes are not engaged in the pressure area. Therefore there is MORE drag. And it's why a Baby can do 74mph with a 225hp motor and a similar Ski Sporter can't (or at least not easily).

Wrong here, there is LESS wetted surface on Bills which means LESS drag

Of course a performance hull achieves full plane. Using your numbers it's between 30-50mph....(I'm not sure at what speed the hull is 100% at plane) and stays on full plane upward to max speed. Once at 100% plane the boat rides no higher (please see explanation of ride height).

NO Donzi 16 stays at an identical ride height from 50 mph to 84mph.

Angle of attack will increase or decrease the wetted surface and therefore effect drag. Again there is no difference for I/O or OB in terms of hull drag.

Wrong again, say angle of attack is constant at 5 degree from 40 to 84. 600lbs less weight means more wetted surface. That is just physics.

Wrong again. 600lbs extra weight means more keel is on the water EVEN though the strakes are not playing a role. In a performance boat, it is not like an on

Conceptually, I am correct that the lack of inner strakes in the pressure area means more wetted surface and more drag. The pictures of both boats bear this out. The difference in hydrodynamic drag from the hull of a Ski Sporter Super Strangler and a Ski Sporter 430HP I/O when both at 100% plane, is zero.

The 21" straked hulls are more efficient through the entire range of speed. As I have shown they have less wetted surface and less drag. I don't know how much power is required to achieve speeds of 68, 75, or 84mph. I can tell you that a 21" inner straked hull will do it more easily (with less power) and probably do it more quickly than a 41", 55" or 58" inner straked hull.

As you can see, strakes serve more purpose than just providing lift when accelerating from stop to plane and helping stability in the turns. They also reduce drag on plane.

The benefit of wackers is in that they are light, which helps with acceleration and handling. Also because they are light they require less power to get on plane (and stay there) and therefore have more of their available power to devote to increasing thrust. They probably get better fuel mileage and are quite adjustable which helps with optimum set up... And in the case of your Super Strangler, it has less drag from the lower foot. But they are limited when it comes to producing HUGE power.

So, in terms of a 55" inner strake hull achieving 74mph... when looking at a (ball park) similarly powered/weighted 21" inner strake hull... NO comparisons can be made because they are just too different.

Before I go any further, I have to ask you a question and it is no way intended to be disrespectful. What experience have you had with high performance hulls over the years and more specifically what OB performance hulls have you owned? I'm curious.

woobs

01-01-2014, 10:07 AM

Greg Guimond

01-01-2014, 10:11 AM

woobs, what experience do you have with high performance boats? I completely understand your concept, but I'm only interested in how it impacts these two hulls and this discussion. I'm happy to have you prove me wrong as it pertains to these two 16s. So far though, I'm just not seeing it.

woobs

01-01-2014, 10:12 AM

Enough.
I'm exactly on point and relivant to this discussion.

Greg Guimond

01-01-2014, 10:18 AM

Sorry, but much of what you said just does not relate. No hard feelings at all I hope woobs. Can I ask for an answer on the high performance experience? You may have had a lot, I just don't know. Again, I'm more curious then anything else as you obviously have a lot of feedback.

Greg Guimond

01-01-2014, 10:32 AM

The reason a no strake example was put forth is so you could understand the concept.

Apparently you don't understand at all. Please tell me why a hull cares where the thrust comes from?

The theory is correct, not generically correct. Once you understand it then we can apply it to specifics (which you seem to get bogged down in).

I understand it. It's interesting.

Greg, really? Just look at the picture. The inner strakes DO NOT TOUCH the pressure area of the hull and are therefore of NO BENEFIT. This means that the water adheres and moves up the hull until it is ejected from the outer strake. ...More wetted surface area = more drag.

I already agreed with you three times that the inner 55s do not touch the pressure area. I'm the one who highlighted that to you in Bill's 65mph photos. Again, how much of the outer strakes are playing a role in water collision is a needed specific before you can even talk about wetted surface.

Once a boat (any boat, as Donzi's are not majical) is 100% on plane it cannot go any higher. A boat can reach 100% on plane and not be at top speed. It's when the amount of LIFT = The force of GRAVITY.

Wrong, if the Donzi planes at say 40, by 70mph it would be slightly higher, and by 85 more so. We agree to disagree on this one.

I am talking about a constant speed while at 100% on plane. You are talking about a transition in speed from 40 to 84. This is dynamic and each point of data at a given speed will be different from another. In this transition, the lighter wacker will accelerate more quickly and come to plane more quickly given the same amount of power.

I only care about the transition speed from 40 to 84, correct.

You can't compare dynamic performance without a lot of actual data. maybe then you could plot it and compare graphs.... but you can't just pick points of willy-nilly data and make conclusions.

My points are not willy-nilly. They are 65mph, 75mph, and 84mph. While you can't CRAY it, you can estimate it. I have done it multiple times over the years while setting up my boats.

Thank you. Again, no bad intentions. It is ok to disagree.

woobs

01-01-2014, 10:47 AM

Had it backwards......typo. Glad you agree with me and not woobs.

Is that what he said????

Greg Guimond

01-01-2014, 11:36 AM

As I have said it is fine to agree to disagree. I'm standing pretty firm on this one. It's not only based on practical experience with the two Superboat 21 footers, one with a race motor, and one without, a Warlock with two different motors and a 24 degree V, and three different Donzi 16s with a wide variety of motors. Also based on some pretty detailed discussions with a marine engineer and designer.

No slam intended to woobs or your nephew ............ :salute:

Greg Guimond

01-01-2014, 11:39 AM

btw give your nephew the variables and have him plot it out for all of us to see. Maybe he can use it as a case study in class. RPI's a great school. Oh, right, he would probably rather be boating down there! Drats.........I'm jealous.

Ghost

01-01-2014, 11:55 AM

Sure thing Ghost, here is the simple version for you. If the 16 is 600lbs heavier and sits 6" lower at rest, it will sit 6" lower under way until about 50-55mph. At 55mph and above the hydrodynamics change and the depth relationship is altered. It continues to adjust (proportionally) as the speeds increase. The light wacker will have even more of an advantage above 55mph. I can't remember exactly but I believe the math was about 1" less wetted surface for each mph gained above 55mph to start for a wacker 16.

I'm not sure I can make it much simpler for you but would love to hear how you look at it :doh:

Greg, i'm curious if you were able to follow my earlier post with the helicopter analogy.

Continuing that train of thought, let's look further at what's wrong with your logic above. Ironically, the closest your logic comes to reality is that as the two boats start to move, their 6 inches of difference in transom-waterline-height (observed at rest) stays the same until it changes. So far, so good for your logic, except the change doesn't wait until they are up near 50 or 55 mph as you claim, not even close.

Further, you offer no rationale nor evidence why the 6 inches of difference in waterline at the transom would change "hydrodynamically" at 50 to 55 rather than at some other speed. The real (and obvious, btw) point where things change hydrodynamically is where the boats come up out of the hole. This is where they have clearly ceased operating as displacement hulls and have started acting as planing hulls. (The helicopters are now aloft. The old difference in height based on one's extra 600 lbs compressing its springs 6" more? That set of forces is gone. Now their relative heights are determined not by the battle between their weights and some springs pushing against the ground, but instead by the battle between their weights and the lift generated by their rotors, pushing against the air.).

For further clarity, let's not get confused by the messy transition from displacement behavior to planing behavior, where elements of both are significantly in play. Clearly, at 1 mph, the boats are basically lifted by traditional displacement forces only. By 25 to 30, they are, for practical purposes, lifted by planing forces only. The real transition from displacement to planing gets rolling between maybe 8 and 18 mph. But we need not define the messy transition, rather we just need to know that by 25 or 30 mph THE LIFT THAT IS BATTLING THE WEIGHT, AND THUS iS DICTATING RIDE HEIGHTS, COMES FROM PLANING FORCES, NOT FROM THE TRADITIONAL DISPLACEMENT FORCES THAT WE OBSERVED WHEN THE BOATS WERE AT REST.

Do you follow me this far, and agree so far?

woobs

01-01-2014, 12:42 PM

It's not only based on practical experience with the two Superboat 21 footers, one with a race motor, and one without, a Warlock with two different motors and a 24 degree V, and three different Donzi 16s with a wide variety of motors.

Ummm.... what happened to;"specific to Donzi 16, further specific to 55s and 21s", and being concerned with only those two hulls?

Stand firm if you like. I didn't ask for your resume.

Greg Guimond

01-01-2014, 12:46 PM

Ummm.... what happened to;"specific to Donzi 16, further specific to 55s and 21s", and being concerned with only those two hulls?

Stand firm if you like. I didn't ask for your resume.

Geez..........I've had three Donzi 16's. How many have you had?

Greg Guimond

01-01-2014, 12:57 PM

Narrowing it down a bit ..........

Greg, for further clarity, let's not get confused by the messy transition from displacement behavior to planing behavior, where elements of both are significantly in play. Clearly, at 1 mph, the boats are basically lifted by traditional displacement forces only. By 25 to 30, they are, for practical purposes, lifted by planing forces only. The real transition from displacement to planing gets rolling between maybe 8 and 18 mph. But we need not define the messy transition,

I agree, we need not define the messy transition.

rather we just need to know that by 25 or 30 mph THE LIFT THAT IS BATTLING THE WEIGHT, AND THUS iS DICTATING RIDE HEIGHTS, COMES FROM PLANING FORCES, NOT FROM THE TRADITIONAL DISPLACEMENT FORCES THAT WE OBSERVED WHEN THE BOATS WERE AT REST.

I do not agree, there is a "battle" between lift and weight and that battle is moving in tandem as speed increases. The issue with the battle is what are the proportional elements of "lift" versus "weight".

What are the proportional contributions of each at ..............

30mph =
50mph =
65mph =
75mph =
84mph =

Do you follow me this far, and agree so far?