Put a hydrofoil on my fishing boat

[Captain Caveman]

This sounds like a 7-minute abs commercial

 

[QBhoy]

I think the description tells the issue to a "T".

I put a foil on about 40 years ago, when they were first invented, and have had one on every boat I have owned since then. Makes sliced bread look like old news.

I just spent 50 grand on a brand spanking new boat and it performed awesomely well. Put a fin on anyway, just because, and the improvement in performance, top speed, hole shot and prop slip would make anyone want one as well.

Never had a broken anti-ventilation plate, never picked up weeds or debris and ran successfully over 50 boat years.

First I’ve known of one to improve top speed. How does that work ?
i can understand their use in the tiny percentage of situations with small engines and needing help staying on plane...but other than that they are dreadful things and usually only comprising a poorly set up rig or underpowered boat. Any I’ve known of always have a negative effect on top speed. Always.

 

[DeepCMark58A]

First I’ve known of one to improve top speed. How does that work ?
i can understand their use in the tiny percentage of situations with small engines and needing help staying on plane...but other than that they are dreadful things and usually only comprising a poorly set up rig or underpowered boat. Any I’ve known of always have a negative effect on top speed. Always.

Well you would be wrong in my circumstance.

 

[QBhoy]

Well you would be wrong in my circumstance.

Have you tried it with it off ? Just a thought. Not sure of the science behind it making it faster to be honest.

 

[fishrdan]

Well you would be wrong in my circumstance.

X2

I bought my outboard with a StingRay Jr installed. Boat planed quick and had good top end speed, for a 14' jon boat and 7.5HP outboard. After reading about how junky the hydrofoils were, ruining speed and handling, I ripped it off. Be gone snake oil fin!

Well..... My next trip out ,the boat was a dog out of the hole and top end speed was reduced due to a bow-up attitude... Needless to say, I put that junky fin back on the outboard and the great performance returned.

Yes, they may not be right for every boat, but they do work as advertised. Would I put one on my 18'er with a 140HP Mercruiser.. Nah....

 

[DeepCMark58A]

Have you tried it with it off ? Just a thought. Not sure of the science behind it making it faster to be honest.

I have to ask do you read what was posted or do you just wait to post. I never said I added the foil to gain any speed, I used the boat several times last summer before I put the foil on last week.

 

[QBhoy]

I have to ask do you read what was posted or do you just wait to post. I never said I added the foil to gain any speed, I used the boat several times last summer before I put the foil on last week.

So what was I wrong about then ? You are very unspecific. Did you read what I posted ?

 

[QBhoy]

X2

I bought my outboard with a StingRay Jr installed. Boat planed quick and had good top end speed, for a 14' jon boat and 7.5HP outboard. After reading about how junky the hydrofoils were, ruining speed and handling, I ripped it off. Be gone snake oil fin!

Well..... My next trip out ,the boat was a dog out of the hole and top end speed was reduced due to a bow-up attitude... Needless to say, I put that junky fin back on the outboard and the great performance returned.

Yes, they may not be right for every boat, but they do work as advertised. Would I put one on my 18'er with a 140HP Mercruiser.. Nah....

You’ve literally just given an exact example of the type of boat I was referring to. Haha.

 

[DeepCMark58A]

You’ve literally just given an exact example of the type of boat I was referring to. Haha.

You are talking about a post that someone else posted, not me. I never said anything about adding more speed.

 

[JimS123]

I previously posted that I had over 50 boat years experience with a fin. That's 35 years with 1 boat, 10 years with another, 5 years with another, 4 years with yet another and 1 year with the last one.

In no case was it a slap-on and let it go. I always optimize prop size, engine height, weight distribution (if feasible), etc, etc.

In 4 of the cases the speed was not changed. In only 1 case did the fin provide a speed increase. In only 1 case was the fin a detriment, and that was because the boat was overpowered. I didn't take off the fin, I hung a smaller motor on the back.

Now when I say "fin" I mean Mr Doelsher's invention. As far as i'm concerned, the whaletails and all the others are merely modifications just to be different, and do not represent true Engineering.

 

[KennethCot]

MOD EDIT - Spammer

 

[H20Rat]

I put a foil on about 40 years ago, when they were first invented, and have had one on every boat I have owned since then. Makes sliced bread look like old news.

Although I don't quite have your years of experience, my tale is much the opposite. I've ripped off at least 5 fins (refuse to call them foils, they are not) on various used boats I've boat over the years. Some performed better without it and the owner just thought they needed it, some boats ended up with smarttabs installed instead of fins, and my experience has been night and day with tabs vs fins. My only use case so far for a fin has been an underpowered tinny that should have had less weight and a bigger engine. The fin was a band aide for the lack of seahorses.

 

[JimS123]

Although I don't quite have your years of experience, my tale is much the opposite. I've ripped off at least 5 fins (refuse to call them foils, they are not) on various used boats I've boat over the years. Some performed better without it and the owner just thought they needed it, some boats ended up with smarttabs installed instead of fins, and my experience has been night and day with tabs vs fins. My only use case so far for a fin has been an underpowered tinny that should have had less weight and a bigger engine. The fin was a band aide for the lack of seahorses.

The term "underpowered" always gets my dander. Some times it does not refer to "performance" but rather the boat just does not go fast enough for the owner. Unless a boat is GROSSLY underpowered (and that's up to the individual) in most cases acceptable performance can be achieved with an optimum propeller.

In my case our family of 4 happily got along for years and years with a 9.5 HP Rude on a 14' tinny rated for a 25. Funny thing, that was the ONLY outfit I ever had that did NOT have an Aquafoil (or hydrofoil). That is, until I DID put the full 25 on her and found that to be OVER powered.

I don't disagree about the advantages of trim tabs, but I just cringe at drilling a dozen holes in my transom, when in my case a foil meets my requirements 100%.

The definition of a hydrofoil is a aerodynamically designed horizontal "plate" that is intended to provide lift. Just like an airplane wing. A "fin" is a vertical plate that provides more of a steering function. Simply nailing on a flat piece of rigid aluminum (previously reported by some on this site) will provide some of the benefits without spending a lot of money. But, as I have said before I personally believe that the Doelsher design, mounted on the side of the anti-ventillation plate, is the optimum product, as opposed to having something flat or with a curley tail sticking way out back.