Removal of Doelfin

[Ram5773]

I have just installed a manual jackplate on my 14ft Johnsen boat (flat bottom skiff) and I'm running a 25hp Evinrude tiller. The jack plate is a 5in up and down and 5 1/2 set back.

I have the jack plate set so the cavitation plate is even with the bottom of the boat, is this right??? Should I go higher?? I noticed with me in the back driving there looks of no danger of not getting enough water to the motor.

I also have a dol-fin on the engine should that be removed with the jack plate on now???

Any advice would be great.

Thank you Ram

 

[Gary H NC]

Re: Removal of Doelfin

You could go another inch to inch and a half higher as a normal rule.
I would get rid of the fin for sure.

 

[tashasdaddy]

Re: Removal of Doelfin

what year 25hp, you can usually raise atleast 1 1/2" above keel. i would try it with it on, and off. probably off. i hate foils.

posting same time.

 

[Ram5773]

Re: Removal of Doelfin

The motor is a 1972 sportster short shaft. Sorry for sounding stupid but I thought the foils were supposed to be a huge help. Does the jack plate change everything?

Thank you for your reply's

Ram

 

[steelespike]

Re: Removal of Doelfin

foils can be a help and I have had good luck with 2 different applications
a medium outboard 15ft 50 hp and a 18ft 120 hp I/O.That said I believe
trim tabs are the best choice power tabs or smart tabs.With the jack plate the foil would be out of water most of the time unable to assist in anything.Tabs help plane,help stay in plane at less power improve ride and can combat no wake speed wander some I/Os and those with heavy sterns suffer from.Your boat should respond well to careful weight distribution trim and motor height.If you are really heavy you might try a tiller extension so
you can sit in the middle seat.

 

[Ram5773]

Re: Removal of Doelfin

I have about 2 more inch's to go up on the jack plate. I just went and looked at the boat in the garage and I'm actually about 3/4 a inch below the cavitation plate, so I'll jack the motor up and try removing the dol-phin tomorrow test an let you know. I see about trim tabs for the future. I have limited room on my boat so self adjusting ones sound like the way to go????????

Ram

 

[ondarvr]

Re: Removal of Doelfin

The Doelfin needs to be out of the water at speed, having it in the water is what creates all the negative results. This is an application where a foil can (may) help, a foil can help to keep the prop from ventilating under hard acceleration and in cornering, this allows you to raise the motor higher and possibly gain a little speed. It doesn't always help and will take some fine tuning to tell, but since you have one already at least give it a try.

A set of tabs will keep the bow down, but don't help with venting, but tabs have few negative effects and are what most people need.

 

[Ram5773]

Re: Removal of Doelfin

Thank you to all who responded, weather is going to be bad today so going to have to test next weekend.

Ram