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Author Topic:   Hydrofoils
Salty posted 03-18-2002 09:41 AM ET (US)   Profile for Salty   Send Email to Salty  
I have a 17 SS Limited with a C-85 Yamaha. Getting a little porpoising, doesn't plane as quick, doesn't plane very well at slow speed. Thinking about a hydrofoil. Past experience with them was good. Looking at a Sting Ray but I see Doel Fin, SE Sport, The Edge, Atwood's gull wing job and others out there. Anyone with any experience with any of these on a 17'? Would love to hear from you. Thanks.
JBCornwell posted 03-18-2002 11:38 AM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Ahoy, Salty.

I have a SE Sport 300 on one Montauk and a Doel Fin on the other.

Both boats get up quicker and go faster than without them.

Red sky at night. . .
JB :)

padrefigure posted 03-18-2002 03:57 PM ET (US)     Profile for padrefigure  Send Email to padrefigure     
JB--do you run one of these on your OR18 as well?
JBCornwell posted 03-18-2002 04:05 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Not yet, Padre, but I will put a SE300 Sport on it.

Red sky at night. . .
JB :)

Bigshot posted 03-18-2002 04:32 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
I do not run one on any of my whalers. You should not be porpoising if trimmed right and with that 85 you should be able to plane around 3k. My Montauk would hop on plane with the 90 and I weigh considerably more. Is she running right?
Salty posted 03-18-2002 10:22 PM ET (US)     Profile for Salty  Send Email to Salty     
I just had the motor put on by an authorized Yamaha dealer. It's running just fine. Plenty of power, good hole shot, 17 prop, motor is mounted all the way down on the transom in the last hole. Anti-cavitation plate is about 1/2" below the bottom. Had it trimmed under all the way and she still had a bit of porpoising and still needed to plane out a little more at slower speeds. My 18 gallon tank is a little more aft than it should be, something that I will remedy soon, and it was full. You could feel that it needed to be a little more balanced towards the bow. I wonder if a hydrofoil would put it there? If so, which one?
Clark Roberts posted 03-19-2002 05:44 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Salty, I vote for the Doel-Fin! Also suggest that you raise engine so that anticavitation plate is 1"-1 1/2" above hull bottom! This will reduce underwater drag and should increase performance and handling but watch those revs and cooling water stream! happy Whalin'... Clark ... Spruce Creek Navy
Ventura16 posted 03-19-2002 09:47 AM ET (US)     Profile for Ventura16  Send Email to Ventura16     
I vote for Doel-Fins...they made a huge difference for me...faster planing, ability to stay on plane at a lower speed, and a more usable trim range.


Salty posted 03-19-2002 12:21 PM ET (US)     Profile for Salty  Send Email to Salty     
Has anyone had any experience with the "Sting Ray" hydrofoil? They are fairly large with a downturned trailing edge.
Arch Autenreith posted 03-19-2002 12:33 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
I have one of those 'huge' ones but can't remember what one it is. I know there's a thread somewhere around here but can't find it easily at them moment.

Anyhow, I didn't like it and took it off so my offer still stands. I think I paid $25 or so dollars for it and I'll send it free if anyone wants it.

Arch Autenreith posted 03-19-2002 01:30 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
John from CT is now the proud new owner of it.
OutrageMan posted 03-19-2002 01:43 PM ET (US)     Profile for OutrageMan  Send Email to OutrageMan     
I had a Stingray on my 22 OR w/ WD and 250 Yamaha. It was the saving grace of the boat and the best money I have ever spent on it.

I bought the fin to try to help compensate for the torque list caused by that big engine. It almost completely eliminated it. Additionally, time to plane was significantly shortened.

A little story about that time to plane. After installing the Stingray, my father and I decided to water test it. Obviously in the slow no wake zone of the channel, there was no effect. When we cleared the channel, I ained the boat out to sea, and from a dead stop hammered the throttle to see how fast I could get it to plane. When she immediately came out of the pocket, I learned a very important lesson about using that fin.

You see, the added lift on the transom forced the bow down very quickly and sharply. When the bow cane in contact with an oncomming wave, we hit very hard. It was the only time I have ever thought I was going to pitch pull a boat. If it wasn't for the T-top standards to hold on to I think Dad and I would have been thrown to the bow.

Needless to say that after that I was quick with the trim as soon as the boat began to break from the pocket.


Bigshot posted 03-19-2002 01:44 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
Raise that engine before you buy anything. too low is a problem.
John from Madison CT posted 03-19-2002 02:13 PM ET (US)     Profile for John from Madison CT  Send Email to John from Madison CT     

Thanks, I appreciate it. I will post the results here once I get a sense of how it does on my Montauk with 90hp Yammie.

If things don't work out, I will offer it for free to the next guy who wishes to try it.

Muchas Gracias !


Salty posted 03-20-2002 10:49 AM ET (US)     Profile for Salty  Send Email to Salty     
Many thanks to all for your comments
ratherwhalering posted 03-22-2002 03:14 PM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering     
I am considering installing a dole fin, and I was wondering if I will need to raise the engine once the fin(s) are bolted on. The fins are thick, and look like they will add 1/4 inch thickness to the cavitation plate, although in the aft section of the plate. Any experiences with this?
OutrageMan posted 03-22-2002 03:24 PM ET (US)     Profile for OutrageMan  Send Email to OutrageMan     
No need to raise your engine.


lhg posted 03-22-2002 05:34 PM ET (US)     Profile for lhg    
All of those engine mounted "stern lifters" are speed killers (because of additional drag) if they don't pop clear of the water flow once plane is achieved. So you have to hang your engine up a hole or two to achieve this. Otherwise you'll lose about 3mph top end. So depending on where your engine is now, you may, or may not, have to raise it.

Clark Roberts is our "resident expert" on this subject, and I believe this is his finding.

acseatsri posted 03-22-2002 10:17 PM ET (US)     Profile for acseatsri  Send Email to acseatsri     
If the hydrofoil is out of the water at planing speed, doesn't this defeat the purpose for which it is intended? I'm putting one on this year just so that I can run on plane at a slower speed when offshore. It's almost impossible to run anywhere near WOT on LI Sound. 18OR planes at around 16 knots now, was hoping for 12-13 with the fin. Also moving the batteries inside the console to redistribute weight, compensate for 85 pound kicker being added.
boxers posted 03-28-2002 09:59 PM ET (US)     Profile for boxers  Send Email to boxers     
THe doel-fin on my 13ft 40th anniversary transformed the boat. The performance difference was AMAZING. I put a big Honda 40HP on the back and counldn't get the trim right. With the fin on the boat is a breeze to trim and the motor is whisper quiet. TWO THUMBS UP
John from Madison CT posted 03-29-2002 05:45 PM ET (US)     Profile for John from Madison CT  Send Email to John from Madison CT     

You're a gentleman and a scholar !! Got the Hydrafoil in the mail today.

Danke Schoen, Muchas Gracias, Efharysto, Gratzie, ..... Thank you !

John from Madison, CT

Arch Autenreith posted 03-29-2002 09:32 PM ET (US)     Profile for Arch Autenreith  Send Email to Arch Autenreith     
You're welcome. But we need before and after specs!!!


This may become a Continuouswave hydrofoil if it doesn't work out for you. Keep passing it to the next person 'til it finds a rig it likes. Lol.

kamml posted 03-31-2002 09:40 AM ET (US)     Profile for kamml  Send Email to kamml     
I had put a Doel on my previous Merc 50/Montauk. It made a noticeable difference on time to plane and lower speeds on plane. I read somewhere after I had mounted it by drilling two holes in the cav. plate that a single hole would work just as well and lessen the chance of any damage to the cav. plate caused by an under water strike to the fin. My repower 90 Merc. pops on plane without the fin, so no need for one at this point for this motor. I would advise trying it with only one hole in the cav. plate first. Ken

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