How Many of You are using Doel-fins, or other stabilizing fins?

[montenido]

Hi all,

I just picked up a mid-90s Johnson 15 hp 2-stroke and I'm thinking about adding a set of those planning fins that attach to the lower section of the OB. Do any of you use these? If so, are they worth doing?

Thanks, Bill

[MarkJ]

The best $40 I have ever spent on the dinghy.

[SmartMove]

Ditto what Mark said, the best addition to the dinghy yet.

[colemj]

I have used Doel-fins, but prefer the SE Sport 200. Amazon.com: SE Sport 200 Hydrofoil: Sports & Outdoors

However, these really only work well if you are a bit underpowered or really need to get up on plane fast (water skiing). Most people are over-propped and can get the same benefit from going a bit lower in pitch. They do reduce top speed a bit, but will allow planing at a bit lower speed.

If you are getting up on plane easily now with normal loads, and can maintain that plane at 3/4 (preferably 2/3) or less throttle, then these won't help all that much.

If you plan on removing the engine from the dinghy often, keep in mind that these stick out quite a bit and can be cumbersome when moving the engine around and when storing it. The Doel-Fins are the worst for this.

Use your new engine on your dinghy for a bit first to see if you are missing anything. If you have trouble getting on plane, or your bow shoots to the sky while doing so (with correct tilt trim), or you need full or mostly full throttle to keep on plane, then a hydrofoil may help.

Mark

[zeehag]

do it. it works.

[colemj]

Originally Posted by zeehag

do it. it works.

Sorry, blanket statements without reason do that to me.

Bill, my advice here is more sound - actually use your dinghy without them first and see where the possible weaknesses lie before adding them. Also think about how you will need to remove/move your engine and how they may effect that.

I have had dinghy/engine combos that benefited greatly from them, as well as combos where they added nothing and possibly decreased performance.

If you are removing and moving your engine a lot, they are definitely not conducive to that - although some are better than others.

Mark

[zeehag]

i used them for over 15 years in san diego bay on long and short shaft outboards on dinghies and on sailiboats. i didnt notice nay difference with the sloops, but the stability with dinghies was noticeably better. yes 15 years i used copies and i used doel fin. both work..
colemj. do you approve of that one.

[belizesailor]

Originally Posted by colemj

....

If you plan on removing the engine from the dinghy often, keep in mind that these stick out quite a bit and can be cumbersome when moving the engine around and when storing it. The Doel-Fins are the worst for this.

...

And those protruding fins can exert more leverage on the cavitation plates where they attach. Ive seen a couple broken this way...handle w care.

[jeremiason]

I used my Yamaha 15hp outboard on my Achilles 10'.5" RIB without and with the fins and can say without a doubt the Stabilizing Fins improve performance!

I have the something similar to the Sport Marine SE300 and it works well get the boat up on plane and also stabilizes the boat in high speed turns, keeping it from sliding.

I store my outboard on the transom of our sailboat when traveling and have never had any problems with the fins getting in the way.

As far as breaking cavitation plates... Well if a semi flexible plastic fin can exert enough force to break a cavitation plate, then maybe it is time for a new engine.

[bobconnie]

Ive used them on many of my dinks, and all of them have been hard dinks, they help a bunch! I use them on my inshore fishing boat, gets me up on a plane in 10 ft from the time I twist the throttle! Thats with a 40 hp 4 stroke on a 16 1/2 ft aluminum CC flats boat! They really have helped on my dinks, cus I could plane with smaller engines then I could without the vanes! Just my 2 cents

[robert sailor]

I found the one made from aluminum to work better than the plastic ones but that might have been just in my case. The aluminum one was also smaller.

[robert sailor]

Mark J you are running the same dink engine combo that I did years ago and I'm trying to find a good place to get another set.

[Wench'sCaptain]

Originally Posted by colemj

I have used Doel-fins, but prefer the SE Sport 200. Amazon.com: SE Sport 200 Hydrofoil: Sports & Outdoors

However, these really only work well if you are a bit underpowered or really need to get up on plane fast (water skiing). Most people are over-propped and can get the same benefit from going a bit lower in pitch. They do reduce top speed a bit, but will allow planing at a bit lower speed.

If you are getting up on plane easily now with normal loads, and can maintain that plane at 3/4 (preferably 2/3) or less throttle, then these won't help all that much.

If you plan on removing the engine from the dinghy often, keep in mind that these stick out quite a bit and can be cumbersome when moving the engine around and when storing it. The Doel-Fins are the worst for this.

Use your new engine on your dinghy for a bit first to see if you are missing anything. If you have trouble getting on plane, or your bow shoots to the sky while doing so (with correct tilt trim), or you need full or mostly full throttle to keep on plane, then a hydrofoil may help.

Mark

I agree with try it first. But I have had a fin ( different brands) on every power boat I have owned since they came out. Gets you on plane quicker and you can stay on plane at slower speeds.

[builder dan]

I have a mac 360 dinghy with an 18 hp tohatsu motor with 2 heavy divers onboard without the fins it struggled to get onto the plane.With the fins its straight up on the plane without the bow climbing for the sky.Best thing I ever did.I was sceptical about fins before now I am sold on them.

[Wraith_Mac]

Then-- Mid 90s Johnson 15hp short shaft tiller steer with Zodiac Inflatable, went from dog to great with fins. After 15yrs use gave it to mate, still going strong.
Now-- Avon rigid hulled inflatable with elec. start, trim/tilt, reinforced transom, long range tanks, double bottom, w/ Suzuki DT65, plenty of weight.
Added fins soon after I bought over 20yrs ago. Made a great boat even better, leaps out of the hole, with a load, still going great.
In between I have added quite a few sets to friends boats, while results have varied between 'good' and 'outstanding', I have not known a set to have a neutral or negative effect.
Cheers,
Mac