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View Full Version : Prop advice for Scot VanAlstine's boat



donzidon
07-21-2014, 10:32 PM
I purchased Scott's 22, and I finally put it in the water this Summer. Its running well, but I have been having a devil of a time getting it to plane out properly. The prop seems to start cavitating around 2,500 rpm and it stalls out revving past 3,000 so you have to start over. Once in a while it hooks up and takes off for a thrilling ride, but you start the process over when you have to slow down at the end of the bay. I have been trying a variety of trim strategies, but not in seems to wok consistently. I am going to have the prop checked.
Some of you saw this boat in Scott's hands, and I am hoping you can offer some advice based on what you saw. Wish I could ask him.
Also, my nieces and nephews would like to us the boat for water skiing occasionally. What prop might you recommend for that?
Boat is a 1983 22 Classic with a 454 and Bravo 1. Looks like a raised X dimension because the air cleaner sticks up into a neat hood scoop from a Mustang. It used to be outboard powered, and all my experience is with a very5 full fuel tank.
Thanks in advance for your help.
Don

Ghost
07-21-2014, 10:53 PM
What prop is on it now?

Conquistador_del_mar
07-21-2014, 11:00 PM
I purchased Scott's 22, and I finally put it in the water this Summer. Its running well, but I have been having a devil of a time getting it to plane out properly. The prop seems to start cavitating around 2,500 rpm and it stalls out revving past 3,000 so you have to start over. Once in a while it hooks up and takes off for a thrilling ride, but you start the process over when you have to slow down at the end of the bay. I have been trying a variety of trim strategies, but not in seems to wok consistently. I am going to have the prop checked.
Some of you saw this boat in Scott's hands, and I am hoping you can offer some advice based on what you saw. Wish I could ask him.
Also, my nieces and nephews would like to us the boat for water skiing occasionally. What prop might you recommend for that?
Boat is a 1983 22 Classic with a 454 and Bravo 1. Looks like a raised X dimension because the air cleaner sticks up into a neat hood scoop from a Mustang. It used to be outboard powered, and all my experience is with a very5 full fuel tank.
Thanks in advance for your help.
Don

I can almost guarantee that a Revolution 4 would hook up like you want. You might be able to turn the 23P.

Conquistador_del_mar
07-23-2014, 12:43 AM
I can almost guarantee that a Revolution 4 would hook up like you want. You might be able to turn the 23P.

Don, after thinking more about your needs I believe a 21P Rev 4 would be better than a 23P.

donzidon
07-24-2014, 01:00 AM
Thanks for the advice. I will give the 23 a try. The current prop is a Turbo 1. Not sure of the pitch. I will have a prop shop check it. Its great fun, but I want to be able to cruise along in the 20's as well as go fast. Do you think that filling the vent holes would help?
Regards,
Don

Conquistador_del_mar
07-24-2014, 01:10 AM
Thanks for the advice. I will give the 23 a try. The current prop is a Turbo 1. Not sure of the pitch. I will have a prop shop check it. Its great fun, but I want to be able to cruise along in the 20's as well as go fast. Do you think that filling the vent holes would help?
Regards,
Don

Don,
I always leave the vent hole plugs installed which is how they come from the factory on the Revolution 4. I believe the 21P will be more in line with your needs. The prop hooks up like no other prop I have ever run with very little slip. Bill

MOP
07-24-2014, 12:58 PM
There is a possibility that you may need to run a 4 blade, my 22 had a high X a 3 blade would slip a fair bit out of the hole.

RickSE
07-25-2014, 04:19 PM
If the vent holes are wide open then that's more then likely the problem. I'd put solid plug in & if you seem to need slip then start adding some hole back in the vents.

Greg Guimond
07-25-2014, 04:31 PM
Agree, the least expensive thing to do is plug all the vent holes initially. Do you have (4) holes or (3) on your three blade Turbo 1 prop. Also, what is the diameter of the holes?

joseph m. hahnl
07-25-2014, 05:52 PM
Didn't that prop work for Scott? Sounds like you are trimmed up to much when your trying to get on plane. Tuck the drive all the way in and don't nail it full throttle out of the hole, try like 3/4 throttle and as the boat just starts to get up on top trim up a slight bit to slip the prop.:kingme: I'll bet it's not the prop it's your technique:yes:

hardcrab
07-25-2014, 08:17 PM
Didn't that prop work for Scott? Sounds like you are trimmed up to much when your trying to get on plane. Tuck the drive all the way in and don't nail it full throttle out of the hole, try like 3/4 throttle and as the boat just starts to get up on top trim up a slight bit to slip the prop.:kingme: I'll bet it's not the prop it's your technique:yes:


Logical ................. :yes:

donzidon
07-27-2014, 02:40 AM
I had it trimmed all theway in and fiddled with the tabs. It was turning 3,000 rpms and going about 15 mph. The mechanic who checked out the driveline had the same experience. When it finally hooked up it really took off with a nice level attitude. We think that may be the way Scott set it up - all or nothing at all. I am having a prop shop check for damage and to fill the three vent holes. One per blade. I read that they are designed to generate slip at low RPMs to let a lower torque motor get up to speed. Great for an outboard but maybe not do good for a 454. I will let you know about the results of that change when I get to run the boar again in 3 weeks. The 4 blade sounds like it may be more flexible for family boating.
Thanks again for the advice.
Don

VetteLT193
07-30-2014, 09:22 PM
I had it trimmed all theway in and fiddled with the tabs. It was turning 3,000 rpms and going about 15 mph. The mechanic who checked out the driveline had the same experience. When it finally hooked up it really took off with a nice level attitude. We think that may be the way Scott set it up - all or nothing at all. I am having a prop shop check for damage and to fill the three vent holes. One per blade. I read that they are designed to generate slip at low RPMs to let a lower torque motor get up to speed. Great for an outboard but maybe not do good for a 454. I will let you know about the results of that change when I get to run the boar again in 3 weeks. The 4 blade sounds like it may be more flexible for family boating.
Thanks again for the advice.
Don

You need to ease it on plane. Slow and steady on the throttle and hold it at certain points while the boat catches up.

A 4 blade hydromotive clever style prop will fix the planing, increase cruise, but lower top end.

Greg Guimond
07-30-2014, 09:33 PM
Before you "drive" yourself nuts, you need to actually measure the distance the centerline of the prop shaft is below the keel of the boat. Level the trailer and drive first. Who knows what he did when he converted the hull from OB . Once you have that as a baseline you can easily go to the next step.

VetteLT193
08-04-2014, 12:30 PM
Before you "drive" yourself nuts, you need to actually measure the distance the centerline of the prop shaft is below the keel of the boat. Level the trailer and drive first. Who knows what he did when he converted the hull from OB . Once you have that as a baseline you can easily go to the next step.

The boat is documented on here by Harbormaster. It's got a 16.5" X dimension. If memory serves that puts it a half inch up from the Shelby

Jraysray
08-04-2014, 08:18 PM
Unless he changed the prop I ran that prop on my boat. It was Grizzs that was on loan to Scot. It ran fine for me with no blow out to speak of. I also remember Scot not getting more than 55ish out of that boat when he ran with me. I got a 26p turbo from grizz. Vent holes open. Gonna try it on my bigger boat. The guy I loaned it too said it caused cavitation on his though.

Carl C
08-05-2014, 05:54 AM
Bravo 1 4 blade. With a Bravo 1 you will want to run a higher pitch number than with other props. Maybe try a 24p to start.

Greg Guimond
08-05-2014, 06:30 AM
The boat is documented on here by Harbormaster. It's got a 16.5" X dimension. If memory serves that puts it a half inch up from the Shelby

On a converted 22 OB, what does a 16 1/2" X dimension translate into for the boats prop shaft centerline below the keel?

Lenny
08-06-2014, 01:36 AM
... a minimum of 2" too deep... hence why it is hunting for a sweet spot... constantly

donzidon
08-09-2014, 01:37 AM
I am having the prop holes plugged at Nautilus Marine in Trenton, ME and will see if that helps. Now that I have scrolled through all Scott's old posts, I see that he regretted the raised X dimension and complained about blowout. After prop testing with Big Grizzly he was still looking at a Blackhawk drive conversion, which tells me that the problem was not solved.

I will see if there is improvement when I go up there and run the boat next week. If not, it will probably be time to take the writeoff and pass the old girl on to someone else. I will keep my fingers crossed.

Conquistador_del_mar
08-09-2014, 02:34 AM
I am having the prop holes plugged at Nautilus Marine in Trenton, ME and will see if that helps. Now that I have scrolled through all Scott's old posts, I see that he regretted the raised X dimension and complained about blowout. After prop testing with Big Grizzly he was still looking at a Blackhawk drive conversion, which tells me that the problem was not solved.

I will see if there is improvement when I go up there and run the boat next week. If not, it will probably be time to take the writeoff and pass the old girl on to someone else. I will keep my fingers crossed.

Don't give up until you try a 4 blade prop like the Revolution 4.

Greg Guimond
08-09-2014, 06:57 AM
I purchased Scott's 22, its running well, but I have been having a devil of a time getting it to plane out properly. Also, my nieces would like to us the boat for water skiing. What prop might you recommend for that? Boat is a 1983 22 Classic with a 454 and Bravo 1. Looks like a raised X dimension because the air cleaner sticks up into a hood scoop. It used to be outboard powered. Thanks Don


The current prop is a Turbo 1. Not sure of the pitch. Its great fun, but I want to be able to cruise along in the 20's as well as go fast. Do you think that filling the vent holes would help?


I had it trimmed all the way in and fiddled with the tabs. It was turning 3,000 rpms and going 15 mph. When it finally hooked up it really took off with a nice level attitude. I'm having a prop shop check for damage and fill the 3 vent holes, 1 per blade. I read they're designed to generate slip at low RPMs to let a lower torque motor get up to speed. Great for an outboard but maybe not good for a 454. The 4 blade sounds like it may be more flexible for family boating.


I am having the prop holes plugged at Nautilus Marine in Trenton, ME. Now that I have scrolled through all Scott's old posts, I see that he regretted the raised X dimension and complained about blowout. After prop testing with Big Grizzly he was still looking at a Blackhawk drive conversion, which tells me that the problem was not solved. I will see if there is improvement when I go up there and run the boat next week. If not, it will probably be time to take the writeoff and pass the old girl on to someone else. I will keep my fingers crossed.

You caught me on my first cup of coffee so I will pontificate before I head out to try and burn three tanks of gas on this perfect day. You still have several things to answer Don ...........

1. I have never liked "X dimension" terminology because of the different drives that are out there never mind you can't trade the data with OB power. You"ll need a level trailer, and a level Bravo One drive to the human eye. Then, using a carpenters level, place it on the trailer and adjust the trailer tongue until level and then put it on top of the drives anti ventilation plate and adjust the trim until dead level. Now actually measure the distance that the prop shaft's centerline is below the 22's keel. Try and be precise as each 1/4" makes a difference. Based on Lenny's earlier comment in the thread I'm going to guess that you'll get a measurement of 3 3/4" to 4" prop shaft depth.

2. What horsepower is the car motor making? I'm too lazy to check the old thread.

3. What pitch is the current prop? I don't think you provided that or I missed it. A "Turbo 1" three blade prop is a bad fit for your application as has been mentioned. I can say that even before you measure prop shaft depth. When you said it had three vent holes, I assumed that you could simply plug them with the rubber inserts which are about a buck apiece. It sounds like you are paying to have the prop shop weld them shut? How much will that cost? If they haven't done it yet, stop them. The Turbo 1 is a 14 1/4" prop. If you want traction or "bite" you need both more blade area and 4 blades. This is even more the case if you want to cruise around at 2500-3000 rpms holding plane full of peeps. Depending on shaft depth you may even want to get into 15" diameter props but certainly at least 4 blades and 14 1/2".

4. As I remember that 22 when it had the V8 wacker on the backer had a set of big trim tabs on it. Are those same tabs still in place?

There are your homework questions before you sell it. :) Btw, what state are you and the boat located in?

donzidon
08-11-2014, 10:06 PM
Greg -
Thanks for the homework assignment. I will measure the X dimension when I pick up the boat on Thursday.

I live in Los Angeles, and the boat is up in the Bar Harbor, Maine area. Not very practical, but I hope to spend my summers up there when I retire.

I think the motor is around 300 HP. Scott said it has everything short of a forged crank. It is a 454 Mercruiser with a new Holley carb. Starts easily and runs smoothly.

Those big Edie Marine tabs are on the back. Very touchy and Scott had the wired the opposite way from my X18. Made that first high speed run exciting. I ordered the shorter tab pieces from Edie, and I hope they will bolt on to the rams.

The prop shop will verify pitch and check conformance while plugging the holes.

I am hoping that the X dimension is not too radical when I measure it. If it is, I will try a four blade prop. If not, the boat is probably better off in the hands of someone who will be happy running it for speed.

I will let you know what I find later in the week. Will keep my fingers crossed.

Regards,

Don

joseph m. hahnl
08-12-2014, 08:50 AM
I am having the prop holes plugged at Nautilus Marine in Trenton, ME and will see if that helps. Now that I have scrolled through all Scott's old posts, I see that he regretted the raised X dimension and complained about blowout. After prop testing with Big Grizzly he was still looking at a Blackhawk drive conversion, which tells me that the problem was not solved.

I will see if there is improvement when I go up there and run the boat next week. If not, it will probably be time to take the writeoff and pass the old girl on to someone else. I will keep my fingers crossed. So there it is :yes: He must of wanted the black hawk for the duel prop bite. I think any three blade at this point is not going to get the bite with out cavitating. It sounds like Scott and Grizz went down that avenue, with out success. I think your best bet is to find a Boat shop that will lend you a 4 blade prop to test. or even a member here will step up:kingme:


REYNOLDS RACING AND MARINE

Switching Among Propeller Types/Families
When changing from 3- to 4-blade, are the pitches the same? If you're changing to propellers manufactured by Mercury, the answer is "yes!" For example, a 4-blade propeller is designed to run at elevated transom heights (normally 2 to 3 inches above the transom). The 4-blade's aggressive blade design and larger diameter help gain a performance advantage. When compared to a 3-blade propeller at the same transom height, the 4-blade will exhibit a lower engine RPM but, when the engine is raised to the proper operating height, the RPMs of both propellers are close.

Greg Guimond
08-12-2014, 03:07 PM
Greg - Thanks for the homework assignment.

I will measure the X dimension when I pick up the boat on Thursday. I live in Los Angeles, and the boat is up in the Maine area. The prop shop will verify pitch and check conformance while plugging the holes.

I wouldn't be concerned. Once you know how deep the propshaft is there are a few very good options. I never understood why those monster tabs were on the back, even with the V8. I think this is a picture of the boat.

Greg Guimond
08-12-2014, 09:31 PM
.
And I think this is the prop you have on the boat currently I believe. 14" diameter and three blades.
.

donzidon
08-14-2014, 10:23 PM
That is the boat, monster tabs and all. It does look pretty. Now the bottom is red.

I ordered the shorter tab bottoms from Edie Marine, and I am waiting for them to arrive.
That looks just like my prop.

I picked up the boat again today. The prop shaft in the outdrive is 6" below the bottom of the V. Maybe 6.25" but no more than that. I put a yardstick along the bottom of the boat, marked the drive and measured down from there.

If I pull up the tabs, carefully adjust the drive to be parallel to the boat bottom (just short of full down) and find a wake or some chop, I can get up onto a plane off the top of a wave and take off.

However, any attempt to trim up at speed to carry bow higher causes the prop to break loose. Any but the most gradual turn has the same effect. Also, the speed gain does not feel proportional to the RPM gain over 3,000 RPM. It felt like it topped out in the low 50s. That dry exhaust is really really loud once you go over 4,000. My mechanic won't let me put the mufflers on because the extended tips are so close to the water's surface that he worries about water coming in when slowing down.

Otherwise the boat is running very smoothly. I just don't have a lot of trimming options, so I can't pick the bow up in rough water or to make it really go.

regards,

Don

Greg Guimond
08-23-2014, 08:40 AM
That is the boat, monster tabs and all. It does look pretty. Now the bottom is red. I picked up the boat today. The prop shaft in the outdrive is 6" below the bottom of the V. Maybe 6.25" but no more than that. I put a yardstick along the bottom of the boat, marked the drive and measured down from there. Don

I don't currently own a 22 Classic but one of the guys will comment on 6" below the keel. Carl might see this and measure his 22 Classic for ya :yes:

With a drive that deep, you can instantly cure your planning problem by switching props to either one of these 4 blades - Mercury Rev 4 or PowerTech OFX 4. The OFX 4 will have more bite and traction in the low rpm range while pulling a skier or tube and loaded with passengers but the Rev 4 will be 5-6mph faster at WOT. I would junk your current prop and try both of those to see which you like best. You might end up keeping both and using the OFX for tubing and the Rev for high speed fun runs.

donzidon
08-27-2014, 10:49 PM
If I understand the X-Dimension correctly, 6 inches below the V translates into a 16 - 16.25 inch X dimension. I have read on other threads that the stock X dimension is 14.5" and the Shelby is 16.5". One of our members went to the Miami boat show when the Shelby was introduced and had a conversation with a Donzi engineer in which he stated that the Shelby X was a bit too high. If I have this right I am a just bit deeper than the Shelby, so it stands to reason that I can make this work with a 4 blade prop. I will buy the 21 pitch Revolution 4 over the winter and look forward to next Summer.

Thanks again for your help.

- Don

Conquistador_del_mar
08-28-2014, 12:41 AM
I will buy the 21 pitch Revolution 4 over the winter and look forward to next Summer.

Thanks again for your help.

- Don

Excellent choice - it should make it run like a dream.

donzidon
09-09-2015, 09:33 PM
Just wanted to thank everyone for their advice regarding the appropriate prop on my boat. I installed a Revolution 4 21 pitch this year, and the cavitation is almost all gone. Boat runs 65 on GPS at 5,000 RPMs.

Now my only problem is the tabs. Eddie Marine will only sell a complete system with the pumps and switch. I am going to try and cut them and maybe replace the rams with something else to avoid spending $2,500. I would not buy their product knowing that you can't buy a spare part if you damage something. This summer I just took them off.

.... and I may have to do something about that dry exhaust. My cousin clearly hear the boat on the golf course a mile from the water. May be a bit much.

Thank you again for all the good advice.

Don

Conquistador_del_mar
09-09-2015, 11:26 PM
Just wanted to thank everyone for their advice regarding the appropriate prop on my boat. I installed a Revolution 4 21 pitch this year, and the cavitation is almost all gone. Boat runs 65 on GPS at 5,000 RPMs.

Now my only problem is the tabs. Eddie Marine will only sell a complete system with the pumps and switch. I am going to try and cut them and maybe replace the rams with something else to avoid spending $2,500. I would not buy their product knowing that you can't buy a spare part if you damage something. This summer I just took them off.

.... and I may have to do something about that dry exhaust. My cousin clearly hear the boat on the golf course a mile from the water. May be a bit much.

Thank you again for all the good advice.

Don

Great news that does not surprise me. The Rev 4 props are wonderful for so many applications!

fysis
09-10-2015, 02:38 PM
Do you have any pics of the drive,tabs,hood etc. How fast was the boat with the outboard setup. How much power from the 454 now.