Hydrofoil on 50hp Merc

[andrewkafp]

I recently bolted a plastic Hyrofoil on my 81 50hp 4 cyl Merc. Haven't had the chance to try it yet, (Working, Domestics etc) But what do guys think I should expect ?<br />This is roughly how the 14ft F/Glass boat performed without the foil.<br />3000 RPM @8-9knots against a fairly strong wing and 1ft 6in waves.<br />4000 RPM @ 16-17 Knots but not on plane yet..<br />4500 RPM On plane at 23Kts and picking up speed<br />5000 RPM around 28Knots.<br />WOT Not acheived due to wife panic attack and nearby small boats (Too much wake)..and occupant looked to be not happy.

 

[rickdb1boat]

Re: Hydrofoil on 50hp Merc

Unicorn <br /><br />You should expect a much better hole shot, much quicker to get on plane(By 4000 RPM's certainly), more reponsive handling, especially at lower speeds, but a possible loss on the top end. Some say it has not affected top speed. Just have to try it and see. I have not seen a loss in top speed on my 16' runabout, if trimmed properly. No change on my toon either. Just better acceleration and handling!

 

[andrewkafp]

Re: Hydrofoil on 50hp Merc

Thanx Rick...<br /><br />I'll just have to try it.<br />Don't have power trim though. Just the old adjustable steel rod.

 

[tmcalavy]

Re: Hydrofoil on 50hp Merc

I have a 73 Merc 500 50 hp with a doel-fin and here's my 2 cents: Qucker hole shot, better response at the helm, planes quicker and no noticeable loss of top end. It pushes a 15 foot Ebbtide fiberglass fish-n-ski trihull. I'm lucky to get 30 mph, but that's fine with me. If I put the trim rod all the way down, its like the doel-fin isn't there, except for quicker to get on plane. Hole 2 and 3 are where I run cause this is where I get the best of the best. Hole 4 and she will cavitate in tight turns. All in all, a very good add-on for my boat and motor. Good luck.

 

[andrewkafp]

Re: Hydrofoil on 50hp Merc

Thanx Tim.<br /><br />The rod is in hole 2 (Second away from transom) coz that's how it was when I bought it, and if it aint broke I don't normally fix it. But having typed that.. I reckon my top speed would also be around 30 knots which is enough to catch a few fish and get some joy out of boating. So.. Nothing ventured, nothing gained. The fin is bolted on and ready to go. As the local council has our street dug up at the moment installing new kerbs, I cannot get out and try it. But I will post any changes in performance.

 

[Old Jarhead]

Re: Hydrofoil on 50hp Merc

Just a comment on your wake remark. In most cases more speed results in less wake. <br /><br />Next time you're out take notice of your wake size compared to your speed...

 

[andrewkafp]

Re: Hydrofoil on 50hp Merc

Will do...<br />He may have just been a bit upset with me scaring his fish away..