Doel Fin will be tested this weekend

[cablebandit]

Last Friday I took my 12'2" Achilles (air floor) out with a new to me '76 Chrysler 15hp engine. Since it was the maiden run with the engine, I also took a trolling motor and battery which I placed at the front of the boat. It came on plane pretty good with the trim in the 2nd hole as recommended but it would ventilate over waves and during fast turns. I moved the trim down to the bottom hole, lost .5mph but no ventilation.

Yesterday I went out but left the trolling motor and battery at home. With no weight in the front, the Achilles wanted to raise up and took a good bit longer to plane with the trim still being in the 1st hole. I moved it to the 2nd hole and boy she stood up and would never plane.

Today I installed a Doel Fin on the 15hp and intend to test it out tomorrow or Sunday. This thread is a placemarker for those interested in the results. I am hoping that (based on reviews) I can go back to the 2nd hole, plane and have no ventilation....we will see.

 

[Chopperbill]

Re: Doel Fin will be tested this weekend

Anxious for your results. Being new to this I find hydrofoil pros and cons reports all over the board.
On edit: My boat supplier says yes on the hydrafoil (no they don't sell them)

 

[fbpooler]

Re: Doel Fin will be tested this weekend

We have used the Doel Fin and also Sting Ray Jr. on two different boats. They help with porpoising but lower maximum speed due to drag.

 

[cablebandit]

Re: Doel Fin will be tested this weekend

Anxious for your results. Being new to this I find hydrofoil pros and cons reports all over the board.
On edit: My boat supplier says yes on the hydrafoil (no they don't sell them)

I am new as well and want to post the data to add to the reviews that are all over the place.

 

[QC]

Re: Doel Fin will be tested this weekend

Very important that you all consider boat size, OB hp etc. Over time the consensus is that small boats with small OBs, with the ability to raise and the ability to lower or raise the OB on the transom (X dimension), are the key to Hydrofoil success.

 

[Sea Rider]

Re: Doel Fin will be tested this weekend

Some issues to consider.

-Probably need a engine transom height optimization ?

-With top inflated sib, that's tubes, air deck, keel, well ballanced sib, well trimmed healthy engine, once on plane, doel fin must ride paralell to water level, if not, poor angle will drag combo and lose best prop thrust.

-If with time, check if this helps :http://forums.iboats.com/inflatables-ribs/abc-sib-rib-installation-guidelines-628902.html Points 1 to 7 in strict order, skip the rest...

Personally I'm not a big fan of doel fins, slows combo a bit and are great collectors of kelp, plastic bags, banana peels, you name it.

Happy Boating

 

[cablebandit]

Re: Doel Fin will be tested this weekend

Well I got SOME data. I went out with my wife and 3 weenie dogs. I never asked her to move around or sit in a certain spot. I think the Doel Fin really helped with planing but can't be sure since she sat in the front most of the time and had never been in the boat with this motor.. I didn't get a chance to run by myself which is where I will get some exact data to compare. I did notice that I could throttle back pretty good and not come off plane. I am thinking of going to the lake today and will get the real data to compare to.

 

[cablebandit]

Re: Doel Fin will be tested this weekend

i got to run by myself today...well I had a weenie dog as a passenger. It looks like I lost 0-.5mph and it planes easily no matter what hole i put the trim pin in. I also got no ventilation on turns or with any trim hole. I am very pleased and will be keeping the Doel Fin on my motor.

 

[Sea Rider]

Re: Doel Fin will be tested this weekend

For best prop thrust adjust trim hole at a position that gives a paralell boat to water level once boat is on plane and engine restes at 90? angle. Usually cowl sticker paralell to water level.

Happy Boating

 

[cablebandit]

Re: Doel Fin will be tested this weekend

I ended up sticking with the 2nd hole since that gave the highest top speed vs the 1st or 3rd hole. It was only faster than the other 2 holes by .5mph. The Doel Fin made all 3 holes possible and eliminated ventilation 100% in even the 3rd hole

 

[Sea Rider]

Re: Doel Fin will be tested this weekend

If sib is well engine/transom height matched, matched by yourself or factory delivered should not experiment ventilation whatsoever at any trim position (will depend on transom's angle of attack) and at close tight turns.

Happy Boating

 

[cablebandit]

Re: Doel Fin will be tested this weekend

If sib is well engine/transom height matched, matched by yourself or factory delivered should not experiment ventilation whatsoever at any trim position (will depend on transom's angle of attack) and at close tight turns.

Happy Boating

Well it did and the fin sits about 1-2" below the rear of my Achilles but the Doel Fin cured that. Even if it didnt ventilate, I couldn't plane in the properly trimmed hole without putting weight up front. This was an easy and inexpensive solution that solved both problems and no need for weight management...just inflate and go which is why i got this thing.