Doel Fins already fitted

[petrolhead]

My new Mariner 60HP has had those big plastic doelfin things fitted which I have never been a great fan of although being honest have no experience of eother! I would welcome thoughts and opinions. Should I leave them on or take them off with the resultant holes in the anticavitation plate.

I know they tend to be used on motors which are too small, but 60HP on a 14.5 feet boat should be ample, and it has power trim too so can be trimmed in when required for extra lift to her stern.

If I take them off the holes remain.

[sean-nós]

I personally don't like the look of them and think all the do is cause drag, if an outboard company thought they were beneficial then they build the cavitation plate like that.
The holes can be filled with metal putty or fillers and a tip of paint.

[Rapier]

Agree. It's a cheap way to sort out a propellor issue.

[Alacrity]

Nasty. Take 'em orf.

[Tremlett 15]

I personally don't like the look of them and think all the do is cause drag, if an outboard company thought they were beneficial then they build the cavitation plate like that.
The holes can be filled with metal putty or fillers and a tip of paint.

go with this.........


get em off...........

[petrolhead]

great, you all agree with my intention! interested in using putty, that too was my thought. I was going to try a repair to a dink out the skeg, mentioned to rapier just the other day as well....who has tried which miracle repair putty cures to what effect?

[floater]

We used to use Devcon metal filler paste in the workshops when I worked in the factory. great stuff, very handy for the odd misplaced or spare hole. When cured the area could be machined filed drilled or tapped. Not sure of the cost we were MoD so unconcerned with such matters but probably not cheap. Better still countersink both sides of the hole find a nice soft bit of alluminium rod (B+Q sell it) to fit the hole, pein one end and cut off a short section so when inserted in the hole 5mm or so protrudes, then either squash the rod section with a beefy clamp or hold a steel block against the peined side and pein the other side over with a hammer. Once both sides are peined and the "rivet" is tight tidy up the face with a file.

I have tried my Yarecraft both with and without Doel fins and have found no difference in top speed but they help a lot with a skier on the back both acceleration to plane and handling. HoweverI agree they are pig ugly.

Outboard motors are a compromise by necessity made to fit a wide range of hull types and shapes by this token on some boats Doel fins will help on others they will hinder. I would try it first and see. What have you to loose you already have them fitted,

DH