Hydrofoils?

[mr_jman]

I have a 35HP Evinrude that struggles to plane out on my 16' Lund boat. I'm thinking that hydrofoils will really help my problem.

I know many people add these and I'm looking for opinions and web links to ones that have worked really well for you. I'm hoping to buy some and add them prior to my next fishing trip in 2 weeks.

[BobT]

Here's my experience with hydrofoils.

Back in the early 90's I purchased a new Lund Rebel 16 but could only afford to put a 25hp on it. It was rated for 45hp. I found that the 25hp struggled to get the boat on plane if I had two or more adults in the boat (myself included). I added hydrofoils and I was able to trim my motor out a notch and could plane out with up to three adult riders (myself included) on relatively smooth water. Also, according to my GPS I gained about 3mph on top end. It definitely helped with my lack of power. Of course, the 25hp was still under-powered by quite a bit and on rough water it didn't work too well.

About 8 years ago I sold that boat and bought my Sylvan Adventurer 1600 with a 90hp. The boat was already equipped with hydrofoils. Two years ago I decided to upgrade my outboard to a new E-tech 90hp. I was asked if I wanted to transfer the hydrofoils from my old 90hp to my new E-tech and I figured, "Why not?"

I was always under the impression that if hydrofoils were so good then why didn't motor manufacturers design the outboard cavitation plates using the hydrofoil design to begin with? Since the boat is rated at 90hp I am fully maxed out on horsepower so I decided to try running without the hydrofoils to see if it made any difference. What I discovered was operating the steering wheel at higher speed was easier and turning was not quite as responsive or quick. I suspect the hydrofoils added enough resistance that I could feel it in the steering wheel and affected steering to some degree. However, the hole-shot was not as good, I couldn't trim it out as far, and my top-end speed dropped about 2mph.

I much prefer the performance advantage I get with the hydrofoils installed.

[harvey lee]

I have a trolling plate and I put it on to slow the boat down when trolling, works very well.

I also helped with the boat planing off and I also incresed my top end for speed. Thats when I have it up and not trolling of course.

Change in the prop would also help you getting on plane faster but you may lose a tich in top end. I reproped this spring and my boat now almost jumps out of the water and I did lose 3 mph on top end. I only use this prop when loaded heavy and 3 larger adults in the boat.

[Maverick]

Everyone that I know that has one is very pleased. I would do it. I have a 50hp Honda on an older Mr. Pike 16. Works great. I think you will be pleased what it will do for around $50.

[marine_man]

In general, for motors of "higher" HP (usually around 50 hp... can go lower), adding a Hydrofoil masks another issue... typically propping. The hydrofoil is usually added to help planing ability, which indicates the prop installed on the motor is too high of pitch.

There are applications where a hydrafoil is beneficial, for instance, quick planing in shallow water, but in general, they're a cheaper fix for a prop problem.

marine_man

[Sonicrunch]

Don't forget that they reduce speed and efficiency due to increased drag. It's no big deal for small slow boats though.

[BobT]

Don't forget that they reduce speed and efficiency due to increased drag. It's no big deal for small slow boats though.

It sounds like you didn't read my post. I used a hydrofoil on an undersized motor and am using one on my current rig. In both situations, top end speed as well as hole shot were improved. In fact, if one does a search on this site one would find where I purposely removed the hydrofoils from my current rig just to prove it to myself. I reported my findings on this site.

As far as prop pitch goes, my current rig tops out at exactly 5500rpm. If I was pitched too heavy I would expect that I wouldn't be getting that high.

[Gordie]

There are applications where a hydrafoil is beneficial, for instance, quick planing in shallow water, but in general, they're a cheaper fix for a prop problem.

marine_man

This is the biggest reason why I run a Hfoil and on the river getting on plane quick is what I want and I achieve this faster with the Hfoil. Like BobT I noticed that I do run a bit faster with the HF on and I have also noticed that it really makes a positive performance difference when my boat is loaded down. JMO

I run a 50 hp on a 18ft mod-vee flat bottom.

I have tried other props but have not found a suitable one that can do what I need it to do without a HF.

[Sonicrunch]

It sounds like you didn't read my post. I used a hydrofoil on an undersized motor and am using one on my current rig. In both situations, top end speed as well as hole shot were improved. In fact, if one does a search on this site one would find where I purposely removed the hydrofoils from my current rig just to prove it to myself. I reported my findings on this site.

As far as prop pitch goes, my current rig tops out at exactly 5500rpm. If I was pitched too heavy I would expect that I wouldn't be getting that high.

I guess by slow, I meant anything under 80 mph :-)

[Greenhornet84]

I like em on my 17 foot with a 75 on it. Been in a few boats that I wish had them so you can get the bow up out of the water.

[Rivernut]

I have a 91 Rebel with a 25 yamaha, absolutely no trouble getting on plane. I have had two other 16's with 25's on them and never was an issue. Im guessing, as previously stated' there is another issue. Good luck.