Hydrofoil stabilizers

R

Raybigdog

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Joined
Apr 19, 2007
RO Number
25950
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2
Does anyone have any experience with the StingRay XPRIII hydrofoil stabilizer? I'm considering putting one on a 25' SanPan pontoon with a 100hp Yamaha, in hopes of better fuel economy and maybe a little more top end. Even just a few miles an hour would be a big difference.
 
I doubt it would make much difference on a pontoon boat but I had one on my 18' Marada and it made a huge difference.
 
What kind of difference--top end, fuel or what? And why don't you think it would help on the pontoon?
 
Hydrofoils help keep bow down and add a little in turning at high speed, but they wont add or decrease speed or fuel consumption. They worked good on my Ski Boat, hole shot pulling 2 skiers and I never saw bow rais at all
 
The foils are best on small boats which cannot use trim tabs--such as RIB's and inflatables with enough power to plane. I have Permatrims on my 28 foot Cat (two 150 hp outboards)--it does put the bow down for bucking into really rough water--at a lower planing speed (planing cat)--but it does slightly decrease the fuel mileage. I don't think it would help with a pontoon boat.
 
Like everyone is saying, hydrofoils want to run parallel with the surface so it's purpose is to pitch the bow up or down as the drive is trimmed in or out and to hold water to the prop in rough conditions or hard turns.

As far as I know, a pontoon boats design makes it run pretty much flat so a hydrofoil would only cause a lot of drag.
 
I installed Doel-fins on a 1988 30 foot Larson Contempra having tabs, twin 260HP engines and Alpha outdrives.

All-around performance improved and I was not able to detect any negatives.
The single largest improvement was a greatly reduced time to plane.
2nd was that I did not have to drag the trim-tabs in the water to keep it on plane at lower speeds. Consequently, the fuel burn decreased.

On dead-flat water, the top speed before the Doel-fins was about 44 MPH. After adding them the top speed went to almost 48 MPH.
Cruising speed at 3,000 RPM also improved.
There was no noticable additional stress placed on the outdrives and service intervals did not change.
 
For $50, I say give it a try. I put one on my 18' bowrider, and it worked well, keeping the bow down when trying to get on plane, and reduced the porpoising somewhat. Trim tabs would have probably worked better, but for $50 and 4 bolt holes in your cavatation plate that can be filled with jb weld later if you decide to remove it, it's well worth the money.
 
Morning Ray

Intersting question. jtybt15,thataway4, TarHeeLBoater and Maxwell Smart and bruceB have given you some straightuseful information regarding your type boat. I can't see how it would help a pontoon boat much, if any....If you are having a cavitation problem, then maybe. Attached is the link to the Stingray Installation guide...please note that while showinging many types of boats to install a hydrofoil on, a pontoon boat isn't one. There are basic big differences between pontoon boats and runabouts (planing hull) type boats and the need to lower the nose and get on plane. If you want more top end, start with your prop and pitch.....

http://www.marine-dynamics.com/StingRay.pdf

I am not usually one to try something first, and I hate drilling any holes in my outdrive, though I am installing a drive shower for cooling. (gotta drill two holes) If you do this, (would be the first on a pontoon boat that I am aware of) please let us know how it turns out...Stan
 
I had a hydrofoil on my 21.5 mariah but later went to the trim tabs which worked much better. The one thing about the hydrofoils is if it gets a crack in it the boat is almost undriveable. Mine developed a small crack on one side. The boat would list from one side to another, it would turn slightly, drove me nuts! I kept looking at the outdrive thinking that somehow it was loose or some other bizarre thing. Found the crack and that solved the problem.
 
I am considering adding a hydrofoil to my Alpha 1 outdrive and wondering if anyone else has any positive or negative comments on whether or not it's worth the effort? I have a 21' Sea Ray Seville 4.3 Merc which can porpoise from time to time when the bow is in planing position -- doesn't porposie when I've got the bow down more in the water while on plane. I've got a 4 blade prop and getting on plane is a breeze even with several adults on board.

Thanks!
 
Amazing. Guy has a pontoon boat and asks about adding a hydrofoil stabilizer. Then several guys with traditional hull boats chime in with how helpful they are. That is not helping the OP guys.

I would not spend $50 and drill holes in the A/C plate to prove to myself that all who noticed it is a pontoon boat are correct as they almost certainly are.
 
Thanks Butch.
Nothing like a guy getting right to the original question to make me feel stupid. I should have been a little more observant before I offered my response, which was as close the the real subject as I am to Venus.

Retract, retract, retract.

Mea Culpa.
 
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