Installing A Doel fin

[iggyw1]

Hi guys,

I have read a lot concerning the use of Doel fins or other types of hydrofoil stabilizers, however, I have never seen my question addressed and I would really like the answer before I try to install the fins on my Evninrude 75 H.P. motor. I have the Speedi four motor, 1965 model. 75 H.P. model #75553.
I have purchased a used set of Doel fins (two separate pieces, not all one piece) that I am going to install on my cavitation plate. Since I bought it used on E-bay, no instructions came with it. My question is this:

How far back or forward on the cavitation plate do I want to install the fins?? I tried in on for size, and I can place it all the way forward, or all the way to the rear, or any place in between. Is the a standard on where to mount it?
Thanks for any help you can give me! IGGY

 

[crb478]

Most that I have seen are even with the front of the AV plate and have more sticking out past the back of the motor.

 

[MikDee]

Having used them before, the back edge of the Doel fin should be even (flush) with the back of the cavitation plate.

 

[iggyw1]

Having used them before, the back edge of the Doel fin should be even (flush) with the back of the cavitation plate.

Thank you very much for that reply. I also thought of going on line and looking at some photos in the ads for the product, and I saw them just about flush with the rear of the cavitation plate as you had suggested. (Didn't even think of looking at the pictures 'til after I posted my question). That's how I will mount mine after hearing from you and seeing the photos of them on line.

 

[iggyw1]

Most that I have seen are even with the front of the AV plate and have more sticking out past the back of the motor.

Thanks for your reply. The only ones that I've seen long enough to almost reach the front to the rear were the one piece stabilizers, and even those were a bit short to go from front to rear. I went on line and looked at pictures in the ads for the Doel fin. (that was an after thought I had after I posted) Thank you though!

 

[metriccrescentwrench]

Yep, I used to have a boat that had the 2-piece fin. I looked at some photos of it to refresh my memory and the rear of the fin was nearly even with the rear of the AV plate (which makes sense as the fin will be more effective the further back it is).

 

[MikDee]

Thank you very much for that reply. I also thought of going on line and looking at some photos in the ads for the product, and I saw them just about flush with the rear of the cavitation plate as you had suggested. (Didn't even think of looking at the pictures 'til after I posted my question). That's how I will mount mine after hearing from you and seeing the photos of them on line.

Thanks for replying, and letting us all know. Yes, I am a fan of them if I need one, no need right now though, but some boats are cured by them. The Doel fin gives you just what you need, without being, oversized, or overbearing like some of the others.

 

[foodfisher]

The further back, (away from the leg)= more stress on the weaker part of the antiventilation plate.