Hydrofoils - pros and cons

[MikeJ]

I've been looking at some of the previous posts regarding hydrofoils, all the posts I've read praise them. I want to add them to my Yamaha F50 to get on the plane at lower speeds. <br /><br />However, what's the catch? If there aren't any notable draw backs, why arent they factory fitted? I think I've missed something here...<br /><br />Any advise greatly appreciated, Thanks.

 

[DJ]

Re: Hydrofoils - pros and cons

Mike,<br /><br />They do not always work. <br /><br />First off, the engine has to be set up correctly. The cavitation plate should be even with the keel, or slightly above.<br /><br />In some cases they can improve planing performance. In other cases they cause handling concerns.<br /><br />THe good news is that they are not that expensive, trial and error are the best methods of testing.

 

[Dhadley]

Re: Hydrofoils - pros and cons

They dont work in every situation. If the X dimension is too low (motor mounted too deep) they can actually pull the back of the boat down. The idea of the fin is to allow the motor to have a greater X dimension thereby reducing drag and allowing the use of a higher technology prop. <br /><br />OMC did expirament with a "winged" lower unit but it wasnt popular for several reasons. Remember that engine manufacturers have to build a motor that can be sold and used all over the world in an unlimited number of applications.<br /><br />Good luck!

 

[FlyBoyMark]

Re: Hydrofoils - pros and cons

A repost from one of my earlier post...<br /><br />"Have you checked the angle of the cavitation plate versus the bottom? How about tucking the motor in more? Gas and battery in front of boat? All the other gear moved forward too? How about a tiller extension so that you can run from middle seat? These choices are better than putting fins on the motor. That should be done only as a last resort...They actually slow the top end down on a boat that small. In addition they booger up your cavitation plate with holes that weaken it. Over the years I have welded many broken cavitaiton plates because of "fins". Remember; "LAST RESORT...." "

 

[MikeJ]

Re: Hydrofoils - pros and cons

Ah, broken cavitation plate - point taken! I'll leave well alone I think...<br />Thanks all.

 

[FlyBoyMark]

Re: Hydrofoils - pros and cons

I thought I would add a little note to this..<br />Most all of the marine repair shops that I do welding work for, I get this standard little response from the mechanics: First they snicker with the Mutley laugh, then they tell me how they love to charge for the fin then charge for fixing it, and then how they would NEVER put one on their boat....

 

[dstuard]

Re: Hydrofoils - pros and cons

I have one on my boat and sometimes it tries to lean to one side. Could this be caused by the fin? I think I will take it off and try it.

 

[Dhadley]

Re: Hydrofoils - pros and cons

dstuard - I would bet that the fin is causing the lean BUT the reason is most likely because the motor needs to be raised. I would bet that one side of the fin is getting pressure on top forcing the boat over. This is one reason they usually dont do well on I/O's. Just try to visualize the fin under water and I'm sure you will understand.<br /><br />Just as a note I have fins on my boats that run over 80 and have never broken a cav plate but I do know some brands are more brittle than others.<br /><br />Good luck!

 

[steelespike]

Re: Hydrofoils - pros and cons

We have 2 Doelfins in our family One on 50 <br />Evinrude on a 15 ft Starcraft Nova. We ran it from<br /> about 1990 to about 99 and only removed it<br /> because we didnt need it on the new pontoon.<br /> Mom used to get stuck in the rocks and mud every fall and never had any trouble with fin or cav. plate. Other is on 18ft Cobia with 120 IO From<br /> 1990 to present.Never any problem.They do a wonderful job with no noticeable loss of top end<br /> I think if you hit something and break your lower unit you were probably going to bust something anyway except in some rare cases.