Doel fins, do they work?

[Laundryman]

I have a 2.9m inflatable with airdeck and keel, powered by a 8hp Mariner 2 stroke. It goes well but the bow rides really high. The motor is well within the the recommended power and weight limit. I have played around with the transome angles without success. Do these Doel fins work and do you think they would bring the bow down? Thank you

 

[rivonia]

The simple answer is YES they do work. Get the larger size and not the small ones.

 

[whisper]

Well I agree that yes is the answer but we had a handling problem that made us decide to remove them.
In any sort of seaway, going down wind, they cause the stern of the boat to get picked up by the waves more than normal and you are in danger of broaching. The only way to prevent this is to increase speed, which may not be sensible/legal etc in the particular circumstances. Furthermore, hard bursts of reverse should be avoided so that the transom doesn't try to dive underwater.

If you only go out in flat water and are not heavy handed then the advantages outway the above cons.

 

[Davy_S]

They work very well! but the Attwood hydrofoil works far better than the Doelfin, simply because it is gull winged shaped and rises out of the water on the plane, unlike the Doelfin.
No problems whatsoever in a following sea, I still use the Attwood on a small fishing boat (planing hull) best thing since sliced bread, the boat rides steadier and will maintain planing speeds without throtle adjustment at lower speeds. ie, it is not either on or off the plane, it is constant. Also the attwood produces a higher top speed than the Doelfin dou to less drag.

 

[Fantasie 19]

Stupid question - and it really is meant as a quest for information - why would you not just sit further forward in the boat??? Perhaps use a throttle extension??

 

[Laundryman]

Tried that. In fact i dont need a throttle extention. I can set the throttle, move forward and steer the boat just by shifting my weight. Bit scary though! I would prefer it if it would just level out on its own. I will buy some fins and report back if if they work or not. Thanks

 

[Rum_Pirate]

I used doel fins on my boat 22'0" Mako with (2 x 90hp outboards).

I now have new 85hp Yamaha's but do not use doel fins for fear of voiding the warranty.

The doel fins really worked. They do get you up on the plane quicker and allowed me to throttle back to lower revs and cruise along staying on the plane.

When I opened the throttles fully they gave so much lift that the whole boat started to dance/waggle.

 

[Tranona]

Tried that. In fact i dont need a throttle extention. I can set the throttle, move forward and steer the boat just by shifting my weight. Bit scary though! I would prefer it if it would just level out on its own. I will buy some fins and report back if if they work or not. Thanks

If it runs flat when you move weight forward then that is your answer. Think you will find that all inflatables act in that way and not sure that fins will help. Will be interested in your findings, but I think I would save the money and just trim the boat properly.