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View Full Version : 80+ mph....time to upgrade the tabs?



zimm17
07-15-2007, 08:44 AM
I'm hesitant to run my bennett trim tabs down when I'm running over 80mph. Since not much of the hull is in the water- one of the local guys I met on the dock said I should be running some K-planes to help keep everything settled at top speeds.

Should I be looking at a set of 280 k-planes? Maybe go with eddie marine or dana tabs? Will it make much of a difference for $2000+

justleft
07-15-2007, 10:45 AM
When my 22c is running WOT the tabs are high and dry. But I am no where near 80 mph !!!!

Any tab at all makes my nose run too low and these gals have been known to bow steer.

Any tab upgrade would be mostly for bling. IMHO (But I like bling)

I don't think there is too much difference between the brands. I would go with the ones that have a seperate pump per tab.

ChromeGorilla
07-15-2007, 12:04 PM
Catch22 runs 90+ and if I recall correctly he has 280's on his boat. I thought I remember him saying he thought they were too long for him.

A pair of 180's may actually be better for you.... just food for thought.....

blackhawk
07-15-2007, 12:08 PM
IMO it depends on what type of water you run in. If running in relatively flat water most of the time the Bennetts should be adequate. If you run in some good sized chop and use the tabs to run level I would want the K-planes

I ran the 280s on my Blackhawk and also have them on my Pantera. I run in some nasty slop sometimes and use the tabs to keep her running level and I'm glad I have the K-planes on there.

Just my $.02

catch 22
07-15-2007, 06:06 PM
Catch22 runs 90+ and if I recall correctly he has 280's on his boat. I thought I remember him saying he thought they were too long for him.
A pair of 180's may actually be better for you.... just food for thought.....
Chrome, You remember me saying something was to long for me but it wasn't the K plains. :eek: At WOT the K Plains are high and dry. Anything above 55 or 60 mph they are out of the water. Unless there is a weight issue or sloppy water. Yes I have 280s and they have worked flawlessly for 3 1/2 years. :yes:

Cuda
07-15-2007, 08:12 PM
I have K planes on my Formula, had Bennets on my Minx, and I rarely used either one. I don't worry about them on the 22, since it doesn't have any. The K planes shouldn't make a difference at 80+, because if you're running that fast, the water is probably smooth, and the planes should be out of the water.

BigGrizzly
07-15-2007, 09:40 PM
I run in the 80s too with Bennets they are high and dry too. You haven't prayer of running above 80and change dragging tabs. The guys at the dock love to spend your money don't they. I bet he was a professional racer who owned a Donzi with a shorty and a blower too-Yea Right. Catch has a shorty on his. I have a TRS on mine. As you know who we are my suggestion is listen to us. Save the money for now.

ChromeGorilla
07-15-2007, 10:37 PM
Chrome, You remember me saying something was to long for me but it wasn't the K plains. :eek: At WOT the K Plains are high and dry. Anything above 55 or 60 mph they are out of the water. Unless there is a weight issue or sloppy water. Yes I have 280s and they have worked flawlessly for 3 1/2 years. :yes:


Well poo.... there ya go folks.... I guess I didn't remember correctly.:boggled:

Too long...LOL... your lucky I'm not at home with access to my pctures.....:wink:

zimm17
07-16-2007, 05:19 AM
Thanks Griz. Hopefully I'm done with modifications soon. As soon as I get a oil temp gauge and re-plumb the oil cooler so it gets cooling water first- I should be done for a while. Oh, and getting the ECU dialed in.

blackhawk
07-16-2007, 11:43 AM
IMO it really boils down to how you run your boat. If you run hard in 2'+ slop I would think they would be very helpful. Now, that being said I don't have any experience driving a "normal" classic and they may not need much tab input. I just know that I run the tabs about neutral an the slop with my Pantera and it helps keep the boat level.

If you don't feel the need for them I wouldn't spend the money. $2k is a lot of gas! :D

roadtrip se
07-16-2007, 02:14 PM
Pretty much worthless in my eyes. Wired backwards, too slow to react, and not needed any ways.

I guess I qualify since I get up over 80, barely, on most days.

If you must, I would go with a small k-plane and stay away from the big stuff like a 280. Longer tabs will just slap the nose.
I've run the BHLE with 150's and for a boat that you truly need a bunch of tab to control it, these are big enough and don't introduce other
handling issues.

Look at it this way, now you have $2K to spend on props. Better use of money in my opinion coming from this dock racer, or shall I call it, keyboard racer! I have five for the 22, that I can find, and an example of the "Miracle Prop" on the way for testing.

Never done.

BigGrizzly
07-16-2007, 02:28 PM
I am with Road trip and my boat do well over 80 on most days too. Right now you need to learn what you drive now! When you get to the point that you go 100mph then a new boat is in order. Save the Dollars and spend on gas and come to Lake Eufaula on Labor day.

blackhawk
07-16-2007, 02:36 PM
RT I respectfully disagree on the bigger tabs. The single best thing I did on my Blackhawk was put 280s on there. Why? Because less angle was needed for them to actually control the attitude of the boat. Which equaled MUCH faster reaction.

Zimm bottom line only you can decide if you need a sturdier tab. Don't let some guy at the dock tell you what you need. :D

glashole
07-16-2007, 03:15 PM
RT I respectfully disagree on the bigger tabs. The single best thing I did on my Blackhawk was put 280s on there. Why? Because less angle was needed for them to actually control the attitude of the boat. Which equaled MUCH faster reaction.
Zimm bottom line only you can decide if you need a sturdier tab. Don't let some guy at the dock tell you what you need. :D

I am sure you know blackhawks are a different breed of boats than std 22's
in the case of blackhawks- yes must have k-planes and you can decide from there 280's or 150's

but in relation to the question, I have seen alot of fast 22's that run just fine with the bennett's

blackhawk
07-16-2007, 03:27 PM
I am sure you know blackhawks are a different breed of boats than std 22's
in the case of blackhawks- yes must have k-planes and you can decide from there 280's or 150's
but in relation to the question, I have seen alot of fast 22's that run just fine with the bennett's

Yes I know first hand! :D My point was regardless of what model you have the longer tab will make them faster to react. The 150s were a joke on my Blackhawk.

Maybe the Classic 22 doesn't need tabs at all. Like I said I have no experience with them.

If you never/rarely use your tabs at WFO I can see where the Bennetts would be fine. If you use them often at WFO I would want some K-planes. But that is just me.

Like I said, zimm needs to make the choice based on how and where he drives the boat and what makes him comfortable. :)

BigGrizzly
07-16-2007, 07:01 PM
For all intense and purposes Catch22 and RT have the same boat.
he has a shorty, a blower, hydraulic steering, and a 22 cla$$ic He doesn't use trim unles it is to balance at slower speeds. Since he really does 90mph it is safe to say he DOES know how to go fast and stable in a Cla$$ic. He has Kplanes but doesn't use them. RT has virtually the same boat, the shorty 80 mph and never tries to steer anyone in the wrong direction except Don cig, but no body is perfect. So the point is I feel sorry for the guys who can't drive their boats without using the trim tabs.

Cuda
07-16-2007, 07:15 PM
Catch told me he only uses the K planes to get up on a plane, probably due to the shorty drive. The other times he uses them, is when cruising with a stiff wind or steep chop on his beam, but not at high speed. He also told me when he first had the K planes installed, he about flipped his boat due to the much faster operation of k planes compared to Bennets.

I just figured I'd type it in for him so Gina wouldn't have to.:cistineb:

gcarter
07-16-2007, 07:20 PM
So the point is I feel sorry for the guys who can't drive their boats without using the trim tabs.
Well Randy, there is the point of the later 22's having a 2" LOWER "X" dimension..........
This is a fact and it does take a different driving style.
I'm talking about the boats that recently had their bottoms reinforced because of a difference of stringer location, different motor mounts, and a lower X to (I'm assuming) lower engine placement, which increases the outdrive moment arm and induces porpoising.

blackhawk
07-16-2007, 09:37 PM
So the point is I feel sorry for the guys who can't drive their boats without using the trim tabs.

I think maybe you should say "drive their 22 Classics", not boats. :D

Every boat is different and if the standard 22 Classic doesn't need tabs then you definitely don't need K-planes. My U-19 didn't have tabs on the boat and definitely didn't need them. It would have been a wasye of money.

But I know there is NO WAY you could put the tabs up and just use the drive my Blackhawk or my Pantera, especially in the rough. If anyone thinks they can I will gladly stand on shore and watch! :D

There is a reason that all the OFFSHORE race boats have K-planes and use them!!!

roadtrip se
07-16-2007, 10:51 PM
Well Randy, there is the point of the later 22's having a 2" LOWER "X" dimension..........
This is a fact and it does take a different driving style.
I'm talking about the boats that recently had their bottoms reinforced because of a difference of stringer location, different motor mounts, and a lower X to (I'm assuming) lower engine placement, which increases the outdrive moment arm and induces porpoising.

George, I disagree with your X-dim comment. My 2001 X-dim is no different than the newer boats and I have checked several newer vintage rides. They are the same X dim and therefore engine placement/CG is the same. Something else is introducing the porpise and by the way, it isn't a universal handling issue with all new boats either. I have seen several run fine without the use of tabs. My boat has never needed tabs with and without the shortie installed. I won't go as far as to say the driver is the difference, because I have tried to control a few of these beasts without tabs and couldn't, but your assumption about the x-dim being lower as a contributing factor isn't accurate from my experience.

If anything, it has been some of the newer boats with a slightly raised X-dim from the typical stock location, that have had the more pronounced porpising issues. The boat that sticks in my mind, the owner will remain nameless, was up 15/16's from my location and when he spaced it down with a 1/2 inch spacer, the boat ran better with less tab input. Not perfect, but better. I have also heard, but not witnessed, that some of the Shelbys will walk their noses too, and they are typically up 2 inches from the stock location.

Either way, a lot of things factor into how these boats will handle with tabs and without the use of tabs.

gcarter
07-17-2007, 05:11 AM
George, I disagree with your X-dim comment. My 2001 X-dim is no different than the newer boats and I have checked several newer vintage rides. They are the same X dim and therefore engine placement/CG is the same. Something else is introducing the porpise and by the way, it isn't a universal handling issue with all new boats either. I have seen several run fine without the use of tabs. My boat has never needed tabs with and without the shortie installed. I won't go as far as to say the driver is the difference, because I have tried to control a few of these beasts without tabs and couldn't, but your assumption about the x-dim being lower as a contributing factor isn't accurate from my experience.
If anything, it has been some of the newer boats with a slightly raised X-dim from the typical stock location, that have had the more pronounced porpising issues. The boat that sticks in my mind, the owner will remain nameless, was up 15/16's from my location and when he spaced it down with a 1/2 inch spacer, the boat ran better with less tab input. Not perfect, but better. I have also heard, but not witnessed, that some of the Shelbys will walk their noses too, and they are typically up 2 inches from the stock location.
Either way, a lot of things factor into how these boats will handle with tabs and without the use of tabs.
Todd, I know there isn't a simple answer, but the examples I'm refering to were evident last June at Lake Powell. I was riding as guest in an '02 22 that had the issue and it all led to a very animated discussion on a shallow bay where the water was a convenient depth where X dimensions could be compared. If I remember correctly all the '02 and newer boats had a lower X, while the older boats had the higher. For variety, there was a Blackhawk, and Rick from Ariz. had his much newer SE w/a 500 and a RAISED X. The oldest 22's were '86's. It seemed the consensus was the boats prior to '02 ran fine w/o tabs while the newer boats didn't except Rick's which did better but his X was still lower than the older boats.
I'm sure others present will chime in here and correct me, but, hey, I'm 62 and my memory isn't infallable! :yes:
It was an interesting afternoon and there was much frustration and gnashing of teeth.

Dr. Dan
07-17-2007, 05:43 AM
:wink:Ok, I will jump in here... since I rode with Poodle in 1000 Isles and he was schooling me on learning how to drive the boat with the Drive Trim only... I have not used the tabs other than for slop or wind control... I run with them 98% of the time in full nuetral position...level with the running surface. This is with Bennetts BTW, this allows my hull to fly level and flat and I have little to no issues in boat attitude.... it's totally predictable.

Also I know where my drive Neutral Trim position is and that allows me to run the 22 with confidence in all conditions. It's my base line for whatever conditions wait for me or come about as we are cruising in an event.

What amazes me is how many people will have no clue what "Neutral Trim" even is? I now only adjust the tabs to keep them neutral... when I wanna pick up some addtional instant boost... I can always lift them up and gain a few mph!:eek!:

How many times do ya watch someone at an Event bouncing all over the place like a friggin Dolphin? It takes little to no skill to drive a boat fast, it takes alot of skill and knowledge to drive a boat fast well, and safe for everyone around you and in the boat. Chine walking lunatics are over their hulls limits...about 5 mph ago... and are not doing any of us favors, if the boats were designed to bounce back and forth and side to side... it would be in every boating safety course... miracle of miracles ... I never read Bob Teague or Tres Martin or anyone else say yeah we really enjoyed the overtrimmed Side to Side Chine Walking feature in this hull.....

With all of this BS said, the largest gain I realized was based on my gain in displacement!!!!!! Which does not require me to over trim my drive to gain speed! I have the luxury of running the boat with the drive in a safe and controlable position in which the hull is designed to handle. What a novel concept to operate the boat in a safe manner ...not out on the edge of sanity trying to impress everyone until it friggin breaks or injures someone.

I agree with Blackhawk and some of the others... you need to decide what is right for you... if it results in you being more confident in driving your boat...and the control is increased... who gives a Sh$* if you are losing a few mph because you are safe? I don't.... I would rather you be a capable captain of your rig.... in the end... you are responsible for your boat, and it's capabilties... good or bad.:spongebob:

Good Luck with whatever direction you go... at least you are inquiring about it....which is a positive and responsible start.

Doc of the Bay :smash:

roadtrip se
07-17-2007, 08:14 AM
Doc is right on. How many of us here have taken the time to look at what the tabs, and other factors, are doing to the handling of our boats and I mean really look? As I re-rigged and set-up the 22, I went through several nuances that incrementally improved the handling of my boat with each change. It is one smooth running monster now, but it didn't come that way from the factory. Setup is critical. It took me over a year to get it all the way I like it.

For example on the tab issue, I am dealing with it on Jill's new Scorpion 18.
It literally drags the tabs to the point of throwing three wakes, due to my opinion, the stops being too conservative. This is introducing some excitement at top end, when one of things catches and hooks the hull and then points the nose towards submarine territory. We ARE going to address this with parts on order and on the way.

Props are another setup issue. I have five different props with five different handling tendencies for the conditions I will be running in that day. How many of us bitch about the handling of our boats, but never try some props to match the conditions we normally boat in or the specific set-up of our boats? It seems like the focus is always on top end and I am guilty of this just like everyone else.

George, FarmerTex called me after Powell last year and gave me the info that you just shared. Just for your information, Yeller's 04 boat has the same X-dim as mine does, and I have seen him complain about porpising here. It is easy to armchair quaterback from a thousand miles away, but there is more to each of these stories. And by the way, comparing the newer boats to something built in the 80's is apples and oranges with all of the changes to these hulls including the reverse chine, changes in the deadrise, weight distribution, and a whole multitude of other issues. Night and day. Look at how these boats sit at the dock, if you want a real eye opener.

Finally, bigger tabs are not necessarily better or we would all be running around with k-plane 380s mounted up. 280Ks are way too much tab for these little boats. Forget about scrubbing speed and reaction times, in my opinion, you will never get these things high enough to keep them from grabbing at the wrong time due to their length. All the guys that I have seen running them bounce their noses, in my opinion, the things are catching water at all speeds and creating porpise. Finally, Gero does an awseome job running his BHLE with the 150s and I can get in the driver seat and run it pretty darn good with those little stubby, kplanes. If I felt the 280s would help him, I would be in his wallet yet again, helping him hook'em up. Another boat that runs great with the 150s is Haver's, no nose bounce there.

My opinion.

smoothie
07-17-2007, 08:40 AM
For all intense and purposes Catch22 and RT have the same boat.
he has a shorty, a blower, hydraulic steering, and a 22 cla$$ic He doesn't use trim unles it is to balance at slower speeds. Since he really does 90mph it is safe to say he DOES know how to go fast and stable in a Cla$$ic. He has Kplanes but doesn't use them. RT has virtually the same boat, the shorty 80 mph and never tries to steer anyone in the wrong direction except Don cig, but no body is perfect. So the point is I feel sorry for the guys who can't drive their boats without using the trim tabs.

:biggrin.:

BigGrizzly
07-17-2007, 10:06 AM
The only X dimension change is the Se and the Shelby which is 2 inches shorter than stock. The stringer placement was done for another reason, but I am not shore what that is. Besides lowering the X would let uou trim more radical both in and out therefore decreasing porpoising. I do allow my bot to bounce a little for several reasons. I have manual gauges for tabs and lower unit so I know exactly where everything is and where neutral tab and drive is. People who see me run don't believe how flat I run. This is no accident or boat/hull design either. It is called Knowing your boat and reading water conditions. People think Doc's is fast, well I have watched him drive it, and some of it is him, not just the boat. So Zim don't get new tabs yet learn to drive what you have then do the rest.

blackhawk
07-17-2007, 10:57 AM
:wink:Ok, I will jump in here... since I rode with Poodle in 1000 Isles and he was schooling me on learning how to drive the boat with the Drive Trim only... I have not used the tabs other than for slop or wind control... I run with them 98% of the time in full nuetral position...level with the running surface. This is with Bennetts BTW, this allows my hull to fly level and flat and I have little to no issues in boat attitude.... it's totally predictable.

This is using your tabs. Just because you're not playing with them all the time doesn't mean you are not using them. You are using them fly level, which in turn allows you to run faster! :D

I have neutral positions marked on my mechanical gauges and do the same thing. Flat water they are high and dry. Sloppy water they are neutral. 2-3 footers they are slightly negative. Once I get them set for the "sweet spot" I forget about them while I am running straight. When turning in the slop I also use them to turn. I know, what a crazy idea!

As far as my Blackhawk was concerned yes I could drive the boat with the 150s. In smooth water or 1-2 foot wind chop they are fine. Where I boat it is usually a washing machine with 2 foot slop. Running the 150s neutral wasn't consistant in these conditions. I would be fine then that one rougue boat wake or 3 footer would come along and launch the boat. I only had one choice, slow down! Running the 280s neutral made the boat more stable and allowed me to trim the outdrive for more speed. Thus, I rode more level AND had more speed.

My Pantera has some rocker in it and with a 3 blade responds very poorly to drive trim position. With a four blade I can use the drive trim to control the attitude better. However, the boat is faster controlling the attitude with the planes. In other words, in the slop I run faster with the tabs neutral and more drive trim than I do with the tabs up and less drive trim. Boat attitude is the same. Plus, I have slow down for the rougue waves with the tabs up. With the tabs in neutral I just fly right over them.

Dr Dan and I have both said it. Drive YOUR boat however you feel comfortable. Water conditions, prop selection, driving style, etc all play a role. This is an art, not a science.

RickSE
07-17-2007, 12:40 PM
I let DonCig & farmerTX drive my boat at Powell this year. We had fun and I got some good comments. I'll let them respond if they want not wanting to put words into their mouths.

Me, I use both the drive trim and tabs to find my sweet spots but everything changes according to speed and passengers. My biggest issue is probably prop based from the Mirage+ since I have a significant torque lean to the port side. I'm used to it but I usually drag the port side tab down to 6.5 or 7 on a scale of 10 to get out of the hole level, 4.5 is neutral. My porpoise can certainly be tolerated but I usually end up cruising with the port tab at 6 and the starboard at 4.5-5 to cruise level with the nose up a little. This is in the 45 to 50-MPH range; faster and the drive and tabs start coming up, slower and they go down. Above 60 to 65-MPH, no tabs are required unless I’m in really crazy water and I only use the drive trim. The tabs come back down when I slow down or the porpoise I run into will toss you out of the boat.

RT, I noticed Don's boat had the 3-wake thing going on. It's a crazy wake to ski behind. :boggled:

As for the original question, after having an 18C w/Bennets and a 22C w/K-Planes I like the K-Planes way better, mainly due to their faster response speed.

yeller
07-17-2007, 08:47 PM
I will admit, a lot of my problems were because of lack of seat time. I was uneducated in driving a Classic (with an I/O) and took everyones word as gospil when they said they don't use tabs. I tried to run the boat with the tabs all the way up and scared the chit out of myself.

I don't use as much tabs now as I did at the start of last season. Also, I have since run the boat with the tabs all the way up, but there can't be more than a slight ripple on the water. You can not run my boat without some tab though. Roadtrip, if you think you can run my boat with no tabs, I'll pull them off and if you can safely drive the boat, I'll refund your airfare. If it can be done, it'll be worth the $ for the driving education. :yes:

BTW: I have dual ram Bennets, but they have been extended 6". I don't know it this helps or worsens the driving as that is how I got it.

gcarter
07-17-2007, 08:58 PM
George, FarmerTex called me after Powell last year and gave me the info that you just shared. Just for your information, Yeller's 04 boat has the same X-dim as mine does, and I have seen him complain about porpising here. It is easy to armchair quaterback from a thousand miles away, but there is more to each of these stories. And by the way, comparing the newer boats to something built in the 80's is apples and oranges with all of the changes to these hulls including the reverse chine, changes in the deadrise, weight distribution, and a whole multitude of other issues. Night and day. Look at how these boats sit at the dock, if you want a real eye opener.
Todd, I wasn't inferring there was any commonality between an '86 and a current boat, only that there was a good spectrum of boats to compare.
Now we all know if you have a Blackhawk drive or Arnison drive there is a dearth of bow lift. A conventionally located Bravo drive will give good response and trim easily. If you lower the drive "Xdim." and have a Bravo, standard leg, you will have excessive bow lift.....it's just physics. Take the lower "X" and add a shorty and you're back to where we started.
The two most benign boats I know of are Catch's before all the mods and Phil Reeds. No tabs needed. Great handling. They are
98 and '99....before the changes.

Mr X
07-17-2007, 09:00 PM
http://smilies.vidahost.com/cwm/cwm/lurk.gif

DonCig
07-17-2007, 09:31 PM
I have one sound piece of advice to pass on to those that are interested; (Trim Tabs versus golf tees) If you play golf, you are aware that we can legally use a "tool" called a tee to place the ball in a position that will yield a higher degree of acceptable results off the tee box. Some golfers like the "furrry bear" types have such superior honed physical control that they do not use a golf tee and would smirk at those that do. But as one of the greatest golfers professed a long time ago; why would anyone be so foolish as to not carry and use a tool that increases ones success?
Think about it a while and maybe the mud will clear.
Next item of clarification; shortys, x dimensions, propshaft location, drive drag charachertistics and center of gravity.
If you have ever studied aeronautical engineering you have some knowledge of thrust angles, drag and center of gravity. You need to understand what items are constants and which ones are the variables.
Donzi Hulls - who really knows? But probably within acceptable manufacturing deviation limits within a short span of time.
Donzi X Dimensions - kind of hard to accurately measure with the engine and drive mounted on the boat. But there are ways to extrapolate the exact X dimension with some other dimensions. I would never fully trust any information given to me by Donzi other than they day they drill the transom hole.
Center of Gravity - not the easiest item for us to measure in the field.
Drive drag charachteristics - have never seen anything ever published on the products that we are discussing. A lot of expert dialouge from those not actually involved in the actual development of the product. You can make some fairly accrate A/B comparrisons by swapping drives back and forth on the same day with the same conditions with your hull and engine, but trying to say that it will cross directly over to another boat has its pitfalls.
So other than gross weight; with and without a trailer, the only other constant that we can usually measure accurately are the lower proshaft location in reference to the subject rear end of the boat (Not the X-Dimension, but the centerline propshaft location in reference to the bottom of the keel/hull). And of couse top speed with an accurate GPS.
As a result we are in the dark on most of the items; so we try to be wizards by extrapolating the various unknowns from a few maybes. Sounds like an exercise in futility to me, but certainly provides a lot of late hours chuckles and moans.
Sorry if I have offended any of you experts out there, but I finally had to stand on my soapbox. Thanks Todd for the inspiration!
Your Friend,
Don
p.s. some insightful reading, if you really want to delve into this subject, lies within the attached documents.

blackhawk
07-17-2007, 09:50 PM
Don, I have to hand it to you, when you get on your soap box you do not mess around!

Very well said.

DonCig
07-17-2007, 10:02 PM
Don, I have to hand it to you, when you get on your soap box you do not mess around!
Very well said.

Scott, thanks. I like your closing signature "SHOW ME DON'T TELL ME!"

Cuda
07-17-2007, 10:08 PM
Using trim tabs is not an option on our 22, since it's not equiped with them. I have no problems with porpoising, but I think that might be due to the different cog because the engine is farther forward due to the transmission. As I said, I never used the tabs on the Minx, and I rarely use the tabs on the 302, not even to get on a plane with the surface drives. The tabs skeer the chit out of me in the Formula, because you can basically make it turn just by using the tabs. I think that's because with the surface drives, there is less rudder area in the water.

gero1
07-17-2007, 10:25 PM
read the water, read the water, read the water....AND NOT JUST 20' IN FRONT OF YOU!!!! know how long it takes before your boat reacts to the tabs

gcarter
07-18-2007, 06:27 AM
Besides prop centerline, the X is also readily measurable. Since ALL gimbal housings from the shaft CL down are identical, whether you have a pre Alpha, Alpha Gen I, Alpha Gen II, Bravo, whatever, if you simply measure from the bottom of the keel to the bottom of the gimbal housing and add the dimension of the shaft CL to the bottom of the gimbal housing......you have the X.
(Stunned silence) :wink::wink:

gero1
07-18-2007, 06:40 AM
hell i'll ask. what is the measurement from shaft c/l to the bottom of the houseing on all of them? please include the black hawk drive

gcarter
07-18-2007, 07:25 AM
Doesn't everyone have an extra gimbal housing laying around????
I do, but I'm out of town. Someone else will have to do it. Blackhawk sits on a Bravo gimbal housing. :)

DonCig
07-18-2007, 08:10 AM
Besides prop centerline, the X is also readily measurable. Since ALL gimbal housings from the shaft CL down are identical, whether you have a pre Alpha, Alpha Gen I, Alpha Gen II, Bravo, whatever, if you simply measure from the bottom of the keel to the bottom of the gimbal housing and add the dimension of the shaft CL to the bottom of the gimbal housing......you have the X.
(Stunned silence) :wink::wink:
George, can you tell me if all Mercury drives can be measured identically as in the following picture that I have taken. The top measuring spot is a metal block that the hydraulic lines from the drive attach to. It is very easy to compare one boat to another boat with this measurement. It gives you both the depth of the prop shaft below the keel of the boat, and a reference dimension as to how high the transom hole was placed in relation to the keel.
And I am embarrassed to say; I do not have a spare Gimbal.......
Thanks,
Don

blackhawk
07-18-2007, 09:01 AM
Well with two people your X is much easier to measure. I run a level off the bottom of the boat and then someone else measures from the level to the crank centerline.

Here's a question for all you experts. What is the center-to-center distance from the propshaft to the input shaft on a Bravo? I am assuming it's about 23"?

roadtrip se
07-18-2007, 09:01 AM
Todd, I wasn't inferring there was any commonality between an '86 and a current boat, only that there was a good spectrum of boats to compare.
Now we all know if you have a Blackhawk drive or Arnison drive there is a dearth of bow lift. A conventionally located Bravo drive will give good response and trim easily. If you lower the drive "Xdim." and have a Bravo, standard leg, you will have excessive bow lift.....it's just physics. Take the lower "X" and add a shorty and you're back to where we started.
The two most benign boats I know of are Catch's before all the mods and Phil Reeds. No tabs needed. Great handling. They are
98 and '99....before the changes.

Okay George, you are still missing, or ignoring, my points on x-dim and the post-2002 production boats. So I will repeat and clarify.

From what I have seen, most every AMH-produced boat, post-95, has the same relative stock X-dim including my 2001. Mine did not have a porpise issue before or after the shortie. Yeller's boat, a 2004, has the porpise issue and requires tab to correct. His boat has the IDENTICAL X-dim to mine. I have driven several post 2002 boats that required no tabs at all and I have also driven some that would have required a visit to the chiropractor without the use of them. My point? There was no big time set up changes made to the X-dim on 22's in 2002 that I am aware of. Other changes in construction, the advent of the 496, yes. Standard X-dim change? No.

So George, you are generalizing on the 2002+ boats. As Professor Tamm so eloquently stated and I attempted in more muddled form, there are a lot of factors that will influence the handling of these things, including the brain in the seat.

So, since we have Mr. Popcorn man chiming in with a big bucket and he has "access" so to speak, perhaps he can share some handling and rigging knowledge on the newer boats. I know several people out here, myself included, that would listen and learn.

DonCig
07-18-2007, 09:13 AM
Well with two people your X is much easier to measure. I run a level off the bottom of the boat and then someone else measures from the level to the crank centerline.
Here's a question for all you experts. What is the center-to-center distance from the propshaft to the input shaft on a Bravo? I am assuming it's about 23"?
Scott, I did a rough measurement this am and the measurement I obtained was 22" on a Bravo 1 case and 14" on my Blackhawk case.


Don

blackhawk
07-18-2007, 09:14 AM
hell i'll ask. what is the measurement from shaft c/l to the bottom of the houseing on all of them? please include the black hawk drive

IF I remember right my X is 17.25" and from the bottom of my boat to the bottom of the gimbal housing(the actual housing, not the trim hydraulic block) is 8". So, that would make the distance from the crank centerline to the bottom of the housing 9.25". But I'm not 100% on my X, just 99%. :D

roadtrip se
07-18-2007, 09:14 AM
I will admit, a lot of my problems were because of lack of seat time. I was uneducated in driving a Classic (with an I/O) and took everyones word as gospil when they said they don't use tabs. I tried to run the boat with the tabs all the way up and scared the chit out of myself.
I don't use as much tabs now as I did at the start of last season. Also, I have since run the boat with the tabs all the way up, but there can't be more than a slight ripple on the water. You can not run my boat without some tab though. Roadtrip, if you think you can run my boat with no tabs, I'll pull them off and if you can safely drive the boat, I'll refund your airfare. If it can be done, it'll be worth the $ for the driving education. :yes:
BTW: I have dual ram Bennets, but they have been extended 6". I don't know it this helps or worsens the driving as that is how I got it.

Yeller, I would have been tempted to take you up on that free plane ticket a year or so back, but since then, I have been introduced to the porpise monster on some newer boats and realize that odds are, I would have to pay.

You mention extended bennetts. I tried a set of extended Victories from Brian Kamath after the re-rig. The things would slap like crazy on the upper-end of the performance band and the nose was all over the place, not to mention a real nice surprise hook for grins, once in awhile. I took them off immediately and put the stock Bennetts back on it. My point, have you tried taking the extendeds off and putting the normal plates on? You might be surprised.

Another tab set-up checkpoint is to take a look at the stop points. You could be dragging those long monsters. Tell-tale sign is the triple rooster at speed. PM me, if I can help.

DonCig
07-18-2007, 09:19 AM
Well with two people your X is much easier to measure. I run a level off the bottom of the boat and then someone else measures from the level to the crank centerline.
Here's a question for all you experts. What is the center-to-center distance from the propshaft to the input shaft on a Bravo? I am assuming it's about 23"?
Scott, the crankshaft centerline on a Bravo case is 11.25" above the large cavitation plate based on my measurements. If you need a picture I can post one.

gcarter
07-18-2007, 07:34 PM
George, can you tell me if all Mercury drives can be measured identically as in the following picture that I have taken. The top measuring spot is a metal block that the hydraulic lines from the drive attach to. It is very easy to compare one boat to another boat with this measurement. It gives you both the depth of the prop shaft below the keel of the boat, and a reference dimension as to how high the transom hole was placed in relation to the keel.
And I am embarrassed to say; I do not have a spare Gimbal.......
Thanks,
Don
I use a thin machinist's scale that measures right off the end and extend it behind that little cast manifold up to the the bottom of the gimbal housing itself. Then there's no variation of various parts, gaskets, etc. But you don't have to go out and buy a nice scale like that. You can use anything thin and stiff...even a manila folder, stick it up there to the bottom of the housing and mark the bottom of the keel and measure to the mark.


Todd, after last year I'm not convinced.......
OK, so here's a challenge........everyone with a 22, regardless of vintage, and drive, take this measurement. Just the measurement from the bottom of the keel to the bottom of the gimbal housing. Oh, I don't know about TRS drives. They're probably different. But any other Merc drive will work.
If we could get one or two from every year from mid '80's to current, it could be some useful data. We could find out what Donzi did over the years, and how much variation there is.

It might be a day or two before I can get back on (goin' to 1000 Islands in the morning) but when I get back I hope we can see some data.
And Todd, I hope they're all the same, and that I'm just getting delerious in my old age....... :confused::confused::eek!::eek!:

gero1
07-19-2007, 11:09 PM
in a previous post you parlayed the intended message to be you had all the measurements from c/l to bottom of the housing and all we had to do was measure from the keel up to the housing. as i am very sure a 68 alpha is about the same as as 75 888 and a 95 black hawk and a 2006 xr....right! every one of these boats are hand built and every one them ACTS MUCH different than the one that came out of the mold before it. i am very sure that .500 of an inch here or there will make a dramatic difference in all of them. please post the measurements!!!!!!!!!!!!

Cuda
07-19-2007, 11:31 PM
Zimm, I just saw where Trick Marine had some billet tabs on sale, but only in certain colors, and quantities.