Hydrofoils on lower units?

ondarvr

Supreme Mariner
Joined
Apr 6, 2005
Messages
11,527
Re: Hydrofoils on lower units?

In the racing and high performance world they were custom designed AV plates made of metal. In the a recreational boating world they were marketed as a cure all for about every problem there is and made from plastic. The foil shape came about because they needed to be made from plastic and were much thicker. Marketing ran with it and so did most of the public.

But you're correct, they work the same no matter what the belief system is.
 

fisherrick

Cadet
Joined
Jul 27, 2009
Messages
21
Re: Hydrofoils on lower units?

Geeze guys, the guy asked a pretty simple question.

Now granted, I am also just a no posting, bottom feeding, one striper who, on occasion asks some of you exalted 50,000 post, grand admirals a simple question and get the feeling that some give answers not to give insight, but to show others how much of a genius they are. Granted, it is a fairly simple question, but to have the first 5 responses directed at how the question should not have been asked seems either self serving or "what the heck are you grunts doing playing in OUR sand box?" But I digress.

A whale tail, foil, or what ever you want to call it is a SIMPLE, INEXPENSIVE DEVICE that is designed to correct minor problems in the relationship of the hull, motor and surface conditions AT ANY GIVEN TIME. Sometimes a boat is loaded one way and is not optimal. Sometimes a water surface is not optimal. Sometimes a motor won't be set up correctly for a certain condition. All are variables that change from day to day. You can take any boat, put as much money as you can stand into it, and get what ever you are looking for under any particular condition. But the water isn't a highway. The surface you're operating on is constantly changing. It changes, you change something to reacquire that optimal condition AT THAT TIME.

But most of us peons have what we have. We simply would like to correct some undesirable condition for the majority of the conditions we encounter. What a whale tail does is level out the peaks and valleys, to a small extent, to make our boating experience more pleasurable for what we are doing or what we need to do. If the trim pin in one hole gives you too much bow down, and raising the pin to the second hole gives you too much bow up, a foil will kind of split the difference. Will it help a 300 pound motor on a 15 ft' boat....no. Will it correct, by providing a small amount of transom lift, a bow up attitude on a fishing boat that tops out @ 23 MPH... probably. Will it help a 70MPH Bass boat, probably not. Of course, if someone puts a $40.00 piece of plastic on a $70,000 boat, the problem is probably NOT the boat.

What ever the case, wouldn't it make more sense to welcome the question as a vehicle to share knowledge, with the intent of enhancing the questioners experience rather than as a self serving platform to spout irrelevancies in the pursuit of ones own ego enhancement?

Kind of reminds me of the kid who asks his parents where he came from. After 2 hours of discomfort over the discussion of the birds and the bees, the kid thanks them and says," I was just curious. Bobby says he is from Cleveland".

Please go easy on us newbies. We might just be the future of what you guys have spent your whole lives learning. However, WE may be the ones teaching YOUR grandchildren.
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,336
Re: Hydrofoils on lower units?

This thread started with an observation and a question asking why. The problem with some topics is that there are 2 different opinions.

Those that have successfully used the product reply with details proclaiming their benefits. Those that were not successful detail reasons why not to use the product. Since apparently there are other factors at play, the logical recommendation is to suggest trying it for yourself. But noooooo, many will demonize the product and imply that those that use them are stupid! (OK, not all of you but certainly some of you).

As the OP pointed out he sees them a lot. That's my observation as well. In a 3 mile stretch on my river there are literally hundreds of boat docks and lifts and I'd have to say that 25% of the lower units have them on. If they were no good the companies that make them would be out of business. In actuality the market is getting bigger.
 

sickwilly

Lieutenant Junior Grade
Joined
Jul 9, 2007
Messages
1,089
Re: Hydrofoils on lower units?

Mine does everything I want it to do. Yup, I have no common sense, just a good ole red neck solution that tweaks my boat to meet my personal boating needs.

Mine is an SE Sport 300 and works great for the purposes I have it on my boat.
 

Fleetwin

Lieutenant Junior Grade
Joined
Nov 23, 2011
Messages
1,141
Re: Hydrofoils on lower units?

Never found a "Fin" that didn't create more problems than it fixed.
 

Maclin

Admiral
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May 27, 2007
Messages
6,761
Re: Hydrofoils on lower units?

On the market expansion topic, I think the creativity of marketers and those effort's effect on sheeple must be considered.

The physics of a fin's shape and mounting point does not make sense regarding the lift provided being a good thing. They may make the engine lighter at first, ok. But it is too far back of the actual hull for it to be a good influence at speed.

A fin can only push up (or down if unstalled upside down as some are!) and even then it is a push coming from behind and under the hul. A hard enough push in the middle and the hull is being urged to go left or right of center, not a good way to start out on plane.

Tabs are on the edges of the stern, and provide a balanced attack if the hull needs help in planing, porpoising or whatever. With the hull now being helped the attack angle of the prop can be adjusted for maximum thrust without neeing to help lift or be helped by being lifted. Tabs can also be made neutral at speed while a fin is always there.

Grab a rectangular piece of plywood at the edges of the short edge and manipulate it fore-aft. Now mount a Z shaped bracket (Z is up-down) in the middle then grab the end of that and manipulate.
 
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sickwilly

Lieutenant Junior Grade
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Jul 9, 2007
Messages
1,089
Re: Hydrofoils on lower units?

Sheeple and lack of common sense because a different solution better suits my boating needs.

I guess so.

bah bah bah

So if tabs suited my needs better I wouldn't have fallen for the creativity of a marketer, but would be enlightened. Yeah, right!

Thanks too for the very informative post about what merc says. Can I sum up. they can get your boat on plane faster (bingo!). They may in some cases affect how your boat turns. They can hurt the anti-ventilation plate. If they cause damage we are not responsible.

So even merc agrees there is a purpose for them in some situations. Thanks!

Bah for now, Sickwilly
 

ssoper

Seaman Apprentice
Joined
Dec 14, 2013
Messages
35
Re: Hydrofoils on lower units?

It got my fishing boat to plane out at lower rpms, so it worked for what "I" wanted.:)
 

bruceb58

Supreme Mariner
Joined
Mar 5, 2006
Messages
30,752
Re: Hydrofoils on lower units?

So even merc agrees there is a purpose for them in some situations. Thanks!
LOL. Putting rocks in the bow of your boat might help it get it up on plane faster as well. Bet Merc would agree that might help but wouldn't recommend that method either.

Cons weighed out the pros on the boat I had it on. I did give it a chance though.
 
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JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,336
Re: Hydrofoils on lower units?

Fwiw nobody I know runs a doelfin, etc on an IO. To no ill effect ...

You never met me.....or my Son.....or my best Buddy.

Your second sentence is not understandable.
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: Hydrofoils on lower units?

I have used two of these devices on two different outboard boats. One was homemade, the other a commercial product (appears to be a Doel-fin; it came with the boat). The homemade one accomplished its mission, which was getting on plane faster. I can't really comment on the efficacy of the Doel-fin as I have only run the boat with it attached. But that boat (see signature) jumps on plane very quickly. I'll have to try the boat without it to see if it makes a difference.
 

lldenney

Recruit
Joined
Oct 30, 2012
Messages
2
Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Lately I've seen a lot of people with bolt on or clamp on hydrofoils on their outboards and stern drives.
Why do people put these on their drives?

There are 114 reviews of the SE Sport 300 Hydrofoil. It gets 4.4 out of 5 stars, with heavy or heavy load boats getting the biggest bang for the buck. Vast majority report stability in turning, most all report elimination of porpoising, most ALL report faster planing out of the hole, and some higher gas mileage from a heavy load or heavy boats and the flatter running.

Naturally, high HP motors on light boats (like high-end bass boats) will get 1-5 mph less high-end speed from the extra resistance, and UNLESS heavily loaded or pulling skiers or tubes, won't see much of a better performance. They already plane fast, and have the least amount of resistance at full speed. If you don't worry about 1-5 mph at 50-70 mph, but want to stop porpoising... this could help according to the reviews.

Installation has been from 2 feet of water to garages. Short and quick, 10-30 minutes. There's a sports clip that eliminates the drilling, costs almost as much as the unit, and has varied comments on it. One guy gave up and drilled the 4 holes in 5 minutes, installed in 10.

114 reviews, 4.4 out of 5? I buy my vehicles with that rating.

They sell from $43-$59+
Check out the reviews at ******** se 300 hydrofoil http://www.********.com/modperl/pro...&cvsfhu=3238393833#pr-header-back-to-top-link
 

dg512055

Petty Officer 3rd Class
Joined
Jul 9, 2009
Messages
92
Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Two words to end this discussion: SMART TABS!
 

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
8,336
Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Two words to end this discussion: SMART TABS!

Oh I agree.

If you drill 4 holes in your anti-cavitation-ventillation plate your motor will rot out and the skeg will fall off and you'll have to spend big $ for a new motor. But the tabs will do a better job and all you have to do is drill 16 holes into your wooden transom and that can do no damage at all cause you followed the directions and used silicone bathroom sealant in the wholes.)

(Friday night, cabin fever, sitting in the boat in the garage freezing making motor sounds with mouth and playing with the destroyer wheel.)
 

pecheux

Lieutenant Junior Grade
Joined
Jun 9, 2006
Messages
1,200
Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

Re: Hydrofoils on lower units? A quick summary of the REVIEWS of a popular hydrofoil

I probably mentioned this on another thread. Installed fins on my small 9.9 hp Johnson which is mounted on a 14 footer fiberglass. Result = get on plane faster with 2 passengers + gear, a little more top speed, and a smoother WOT overall experience.

But It has to be at the right height from transom to water level.

Cheers
 

MikDee

Banned
Joined
Jun 6, 2007
Messages
4,745
Re: Hydrofoils on lower units?

I think I've had a Doel fin on most of the later boats I've owned, and it always helped all around. I am a Fan! One time I decided to put trim tabs on my 1979', 24' SeaRay cuddy 260hp Merc. and sprung for the cost, & my labor. To me it was a big mistake, especially without a gauge. It seems that they took to long to come into play for planing , then they were down too far, I had to correct. Then in a heavy sea, I adjusted them to keep the boat level, after riding awhile, I u-turned, & headed back, when all of a sudden the boat listed violently! I forgot about the trim tabs! I immediately throttled down, and leveled the tabs. I had to correct again. Then another time I was cruising, and noticed the boat seemed to be dragging? Then it dawned on me the tabs were down, Duh! corrected again! Any maneuver I made with the boat, it seemed I was correcting all the time, finally I just gave up using them!
 
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