Hydrofoils?

[caine]

for johnblow and my benefit, we'd like some advise on Hydrofoils

on my old boat (25HP) i fitted one of the cheap 2 peice ones. and i think it did make a difference (but it could just be my imagination.

some advise i have been given is :

-that you only need one if you have problems getting on the plane.(which i dont have)

-also that 1 piece ones are better cause the 2 piece ones vibrate

2 piece ones are about $35, 1 piece ones are around $90

i run a 40hp yamaha on a 4.2m tinnie, it goes good but id like to go better!

im sure foils help you on the plane quicker, but do they really provide better fuel economy and higher top end speeds,

also any advise on fitting them would be apreciated, i think they come with all the nuts & bolts. but i'd rather not drill into my pride and joy. are there any kits available that dont require vandalising your $5k engine

everyones opinion is welcome

[Geoff]

some advise i have been given is :

-that you only need one if you have problems getting on the plane.

Your correct. Also, assist staying on the plane at lower speed. As mentioned , if you do not have a problem getting on the plane then not much point in spending the money.

As far as I am aware foils do not assist with top speed.

One aspect to keep in mind , there have been several horror stories around from boaters using the wing type foils as under certin conditions they can work in reverse , ie one side digs in & flips the boat on it's side.

If planning on adding a "foil" then purchase the one piece unit that extends from the rear of the cavation plate not the wings.

Hope this helps

Geoff

[Guest johblow]

OK, thanks Geoff, i think im getting the drift here - they are like the winged rudders that yachties use to keep the nose in the water. The principal is to provide vertical thrust to keep the back up and the nose down, and as the foil becomes more horizontally pitched, the less effect the foil has (negative feedback for you rocket scientists out there).

I was having visions of my boat turning into one of the hydro foils that used to run on the harbour... i guess its not to be!

[macka17]

OK, thanks Geoff, i think im getting the drift here - they are like the winged rudders that yachties use to keep the nose in the water. The principal is to provide vertical thrust to keep the back up and the nose down, and as the foil becomes more horizontally pitched, the less effect the foil has (negative feedback for you rocket scientists out there).

I was having visions of my boat turning into one of the hydro foils that used to run on the harbour... i guess its not to be!

Hi. I've had several on the smaller motors. 25/40. They help lift you out. Hold your bows down. Plane at lower speeds. Take a bit OFF top speed. and Had no noticble difference to fuel consumption.

Now.. The one on my 90 Etec... That's there cause a bow rider rides bows up. Trims her out. lifts arse up a bit. She runs on fresh air anyway. so that side's not a problem... and outruns the others with Etecs on...

They're better off your boat. Unless you need them for extra lift... or a bit of bows down.

.Most weight in back of boat Like the bow riders. They have all weight behind the wheel..

They have GREAT casting platform at front though...

Regards

Macka17

Edited January 4, 2007 by macka17