Do hydrofoils work?

[Deeps]

I've seen various hydrofoil add-ons at the marine parts store. They claim to get the boat on a plane quicker and create a lift which will take some of the engine weight away, thus increasing speed.<br /><br />Has anyone used these? Do they work? Is it worth drilling holes in my motor?<br /><br />I have a Merc 85 on my 16' tri-hull. It would be nice to have a bit of added acceleration and speed.

 

[crab bait]

Re: Do hydrofoils work?

in this case... believe everything you read... they are the poop !!hands down !!

 

[Deeps]

Re: Do hydrofoils work?

I've read that they can decrease top end speed. Do you think that this would be the case on a tri-hull?

 

[crab bait]

Re: Do hydrofoils work?

if you think you need'um ,, you need'um.. maybe alittle speed .. who cares ,, they work...

 

[Papa Smurf]

Re: Do hydrofoils work?

Installed the Doel-Fin on my 1980, Arrow Glass tri haul with a 70hp merc. Night and day difference. The boat plains MUCH faster. The biggest difference was that my boat stopped porpoiseing.(sp?) This is when your on plain and the front of your boat keeps bobing up and down.<br />Now it is steady. I was scared about installing (mainly drilling) on my lower unit too. This is why I chose the Doel-Fin. It was 2 pieces and is made of some type of rubber/plastic combination. I figured it might snap off before breaking my lower unit. (Probably wishful thinking though) <br />Good Luck<br />Papa Smurf

 

[Deeps]

Re: Do hydrofoils work?

Thanks guys... I will give it a try

 

[Alrobot]

Re: Do hydrofoils work?

I just put one on my 76 Tri-hull Galaxy tonight. Taking the boat out after work Thursday. I will post results for you. I have heard nothing but good about these. I got mine from www.overtons.com for $39.

 

[steve forsythe]

Re: Do hydrofoils work?

I read on this board all the great things about hydrofoils and got one. Didnt read one bad post. They were all right about getting on plane faster and stabilizing the boat.....BUT the one thing noone mentioned is that if you use the boat in the ocean they are a BAD idea. Your nose will plow into oncoming waves quite forcefully if you are not carefull. If the seas pick up you will hate having the nose of your boat being held down. They do reduce top end also by about 10%. If you are going into the ocean and could encounter fast changing seas, then you need retractable hydrofoils or hydrolic Trim Tabs. They are 10 to 20 times more expensive ($300-$500) but very worth it!!! If you have a small boat (under 17') and you stay inland, i would say give them a try.

 

[SeaDawg]

Re: Do hydrofoils work?

Purse Snatcher, maybe it varies by boat. I have a Lowe MT 1760 (flat bottom open hull desigh), with a 50 HP Mariner 4-stroke (with power trim).<br /><br />I tried this last weekend, if I trim the moter "up", I can go slow (around 10 to 12 mph), and hold the nose 6 or 7 ft. above the water. I have a 2 piece fin installed on my boat.<br /><br />HOWEVER, if I trim it the other way (motor all the way "down"), I can be on plane at the same or just above the same speeds.<br /><br />This is with a wide beam (close to 7 ft. at the boat bottom), 17 1/2 ft. length, evenly loaded boat (approx. 1,500 lbs total everything weight).

 

[steve forsythe]

Re: Do hydrofoils work?

i just meant with a heavier boat trying to stay up on plane in say...3-5 foot seas, you want to go slow but not so slow you keep coming off plane. If you go to slow (low rpm's) your motor will really struggle against the sea. So.... you give it more rpm's to stay "up" and your nose gets held down with the foils on. It is hard to find a middle ground. Your boat is lighter and smaller then mine and i am sure that helps a lot.

 

[Deeps]

Re: Do hydrofoils work?

You know what would be nice... hydrofoils that detach and reattach easily. So if you knew you were going to be skiing that day, just attach them, else leave them off.<br /><br />Anyone know of a brand that offers something similar?

 

[Fouled Plug]

Re: Do hydrofoils work?

Most of the brands I am aware of are held on by 4 bolts. With a socket and an end wrench you could pop it off in a couple minutes.

 

[Alrobot]

Re: Do hydrofoils work?

Just got back in from the lake. Man, I sure noticed a difference with the new hydrofoil. It darn near jumped up on to plane. I didn't lose any top speed that I could see. I am absolutely happy with it. I would suggest one to just about anybody I know.<br />Al...

 

[sho305]

Re: Do hydrofoils work?

Have used foils on a couple of 16-19' boats. They get you on plane faster and keep the boat from plowing so much before planing. Good for boats that act heavy in the rear on take-off. They help a little to prevent prop 'blowout' at low speeds too. I could plane slower and holeshot much faster.<br /> <br />The thing is, the cavitation plate they mount on should be out of the water at on-plane speeds; so they should not affect high speed operation at all. If your motor/drive is mounted lower they may not be a good idea and you are being slowed by this even now. Some boats may require the drive be mounted this way, not sure why; maybe better bite for a deep hull. They will amplify your trim setting at below plane speeds. If your plate is clear of the water at speed, you should have no problem. Make sure you use stainless hardware and locking nuts to attach!

 

[GarageGuy42]

Re: Do hydrofoils work?

Here in the midwest they refer to them as whale tails. They may or may not be the same thing but they mount on the outdrive fin,4 bolts etc. It made a huge difference in plane time and no noticable difference in topend. The best part was no cavication on tight turns with the outdrive trimmed out. For $40 it was a very positive experiment.