Hydrofoil Stabilizer

[Nandy]

What do you guys think about it? I had one in my very first boat. it was a john boat with a 10 hp yamaha enduro. It did make a difference in gettting the boat into plane. I even thought it did made it faster, but that was just my imagination I bet.
Anyway, i have a 15 footer trihull wiht a 50 hp ob mercury. It takes a bit before it gets into plane. I mean, it have to be about 20 mph before it does, it dont take a minute to get there however. Will it benefict this size boat/motor?

Thanks!

 

[QC]

Re: Hydrofoil Stabilizer

My signature used to be "Friends don't let friends use hydrofoils" . . .

Let's try and get your boat right before you bolt stuff on to the OB. Trim Tabs are also bolt on, but they know how to get out of the way . . .

 

[thrasher]

Re: Hydrofoil Stabilizer

A second vote for smart tabs or real trim tabs, don't waste your money on a hydrofoil.

Gary

 

[nlain]

Re: Hydrofoil Stabilizer

I will add a vote and recommend Smart Tabs, I have them and like them. I had a hydrofoil on another boat and never did like it.

 

[sickwilly]

Re: Hydrofoil Stabilizer

I love my SE Sport 300 hydrofoil, but we have very different boats.

 

[QC]

Re: Hydrofoil Stabilizer

sickwilly . . . I maintain that if you switched to helm adjustable tabs, without the 'foil, you'd like your boat, its speed and its wake even more . . .

 

[steelespike]

Re: Hydrofoil Stabilizer

First get your boat setup right remove excess weight,if tank and battery are in the stern move them forward even if only a few feet.Your anti vent plate should be even with the bottom of the boat.Try different trim settings.
Ex. if one notch is not enough but 2 is too much you can buy or make a wedge to go between clamp and transom so you can get half a notch.It has been my expierence that most outboards manual trim is seldom ideal without a little diddling.
While I have had good luck with Hydrafoils I have to vote for smart tabs.
Very effective for all sorts of bad habits,excellent factory support.
you will be pleased.

 

[rheagler]

Re: Hydrofoil Stabilizer

I was skeptical about the hydrofoil. I read a ton of thread postings about them being a waste of money. All my local boating friends have them and told me how well they worked to get the boat on plane faster and use less fuel. What finally did convince me to try was the money back guarantee on the one that I bought. I figured all I had to lose was 10 minutes to install it, and 4 small holes on a 25 year old outboard. It took some experimenting to get the motor trimmed correctly, I don't have power trim/tilt. I can't really tell if the boat gets on plane any faster, but it does plane with less power. Fuel economy was dramatically improved. Boat is 1983 Glassmaster, 1982 Mercury 50. Good luck with your decision.

 

[QC]

Re: Hydrofoil Stabilizer

Fuel economy was dramatically improved.

We want data, we want data, we want data (group chant) . . . I can believe that fuel economy would improve at say 15 MPH if the boat previously did not plane until 18 MPH, Howver, I am more curious about higher speed numbers. Every test I have ever seen shows that top speed is decreased with a 'foil, so it stands to reason that at some point fuel efficiency becomes worse . . .

Edit: BTW, my 23 footer planes at 11.5 MPH GPS with helm adjustable trim tabs . . .

 

[Mark42]

Re: Hydrofoil Stabilizer

Sounds to me as if there is something wrong with the boat or the setup. A 15 ft trihull with a good running 50 hp should be on plane at 12-15mph, especially if there is no load. My 14' with 40hp is on plane by 15mph with full load!

So check the following: (Some are duplicates of what others have already suggested)

- O/B in good state of tune and running well?
- O/B trimmed right?
- O/B at right hight?
- No excessive weight (no wet foam in floor)?
- Weight properly distributed?
- Nice clean hull? (no seaweed growing on hull)

I tried a hydrofoil on my MFG, and after playing around for an afternoon, I realized I just had to move the trim pin. I got better performance when I had the motor set up right than with the hydrofoil.

Anyone want a hydrofoil that was used for one afternoon?

 

[luckyinkentucky]

Re: Hydrofoil Stabilizer

Hydrofoils are for people who don't know any better in my opinion. It think it's the 'sucker' advertising that pulls new boat owners in.

I'll admit I had one on my Evinrude 200hp outboard for about a week. Then I took it off and threw it in the garbage at Kentucky Lake, and everything has been better ever since.

 

[QC]

Re: Hydrofoil Stabilizer

Although I hate the stupid things, I am starting to believe that Hydrofoils might be OK on some small dinghies and inflatables. Other than that, there are much better ways to enhance your hull and performance.

 

[sickwilly]

Re: Hydrofoil Stabilizer

Hydrofoils are for people who don't know any better in my opinion. It think it's the 'sucker' advertising that pulls new boat owners in.

I'll admit I had one on my Evinrude 200hp outboard for about a week. Then I took it off and threw it in the garbage at Kentucky Lake, and everything has been better ever since.

I invite you down from our neighboring state to the north next summer to see just how much of a "sucker" I am. We can run with and without and see if you think its worth $50 on my light 19 foot boat.

We'll run at 55 MPH with and 55 MPH without it and you will see I lost no top end.

We will whip around in turns and you can see how damn nice a Stingray handles with a foil.

Then for the real test, we'll pull my 50 lbs daughter on a hydroslide at at 17 MPH with no bow rise with it with a 23 pitch prop, and then well not be able to pull her without it because she would need to tolerate a tow speed in the upper 20s for the boat to plane.

Then you can buy me some beer when you agree that I ain't no sucker for having a hydrofoil, and we can suck that down.

Would trim tabs work better? From what I read here and on the Stingray website I would predict they would. However, they have a tall order to overcome. Trim tabs will be a project for a couple of years down the road when I have finished all my other projects and am itching to do something else to my boat.

 

[rheagler]

Re: Hydrofoil Stabilizer

We want data, we want data, we want data (group chant) . . . I can believe that fuel economy would improve at say 15 MPH if the boat previously did not plane until 18 MPH, Howver, I am more curious about higher speed numbers. Every test I have ever seen shows that top speed is decreased with a 'foil, so it stands to reason that at some point fuel efficiency becomes worse . . .

Edit: BTW, my 23 footer planes at 11.5 MPH GPS with helm adjustable trim tabs . . .

This data probably won't stand up in court, but I will describe my unscientific findings. With no hydrofoil and running between 3/4-7/8 throttle my boat would cruise along at about 26mph according to my gps. One day I took a little cruise, myself and 2 others in the boat from the ramp down the river to the south end of Burlington Island, then north up the river to the "Trenton Makes" bridge and back towards home. I burned a 6 gallon tank bone dry to within sight of the ramp. After putting on the hydrofoil, same trip, same 3/4-7/8 throttle (have no tach), same load of people cruising speed 27mph and used about 4 gallons.
This is what I happened with the hydrofoil on MY boat, I'm not saying every boat will have the same results. If the hydrofoil I bought did not offer the money back guarantee I probably would not have tried it. I wasn't looking for any increase in speed, I was looking to use less fuel and I must say I am happy with it.

 

[Nandy]

Re: Hydrofoil Stabilizer

The motor I have had a hydrofoil which I took off several years ago and I cant find it. Anything I buy in Basspro will have a return guarantee. If i can find a hydrofoil that fit the holes i mgh try it. The tabs also looks good. I can probably set the boat load better. Many options, thanks for the advise.

 

[Drowned Rat]

Re: Hydrofoil Stabilizer

Another vote for Smart Tabs. You won't be dissapointed with this product. However, I've found that the Doel-Fin thingies do have a noticeable effect on smaller boats. I had a 14' tri-hull with a 50hp outboard with a "Fin" and it may have planed a little quicker and a little flatter, but it for sure handled better. It was more stable in turns and it reduced porpoising. It had no noticeable effect on speed. I'd bet you would have similar performance on your boat. That said, Smart Tabs are pretty cheap and perform MUCH better. I don't dislike Doel-Fins but I'll never buy another one.

 

[Mark42]

Re: Hydrofoil Stabilizer

I seriously doubt your tri-hull was designed to perform that crappy. There is most likely something wrong with the boat, motor or overall setup.

Get the fin if you want, but then you will never know how the boat was meant to handle.

I know that some folks posted how well their boats handle with a fin. But the bottom line is boats and outboards were not designed to run with fins. If it was an accepted and proven addition, all outboards would come with them standard.... but they don't, do they.

Fins mask problems, they don't fix them.

 

[JimS123]

Re: Hydrofoil Stabilizer

I got a kick out of this thread, so I just have to reply. Probably won't make any difference, though, since it sounds like everybody has their mind made up. I'm an Engineer by profession, and have been an avid boater for over 50 years. The last 40 years has been spent building, rebuilding and optimizing my rigs. You want data...well, I got more data than will fit on this page.

My current rig is a 19' Stingray, 3L I/O, fitted with custom rear seats to hold portable gas tanks, plus a 10 HP kicker on an OMC bracket. As such, it's stern heavy. The prop is a double cupped SS custom re-pitched to 22" to get optimum results. I also have fixed mount trim tabs, which helped by allowing more trim without porpoising (thus faster speed). Still was not completely satisfied, though...had to try a Doelfin.

The boat does 51 mph. Not too bad for a 4 banger, is it?

My test course is 26 miles long and has a gas dock on it. I do 2 passes (52 miles total - once each way). Speed is charted by GPS. I do a gas fillup at the beginning and end. Same boat load, try to do it in similar weather. In addition to mileage, I chart speed at 500 rpm intervals and put it into an Excel spreadsheet. I consider 30 mph to be my cruising speed.

OK...here it is...

The Doelfin planed at 4 mph lower speed, top end was exactly the same, cruise speed was at 300 lower rpm, gas mileage improved by 0.45 mpg. Now that sounds good and all, but the real improvement was in the fact that the bow rise was virtually eliminated.

Just last month I put one on my 14' aluminum Sea Nymph, right after I upgraded to a new Yami 25hp 2-stroke. I have not finished charting all of the data yet, but the performance improvement has been outstanding.

Nuff said.....

The ONLY boat I own that doesn't have a Doelfin is a '52 wood Lyman with a '52 Evinrude Big Twin. She runs perfect with no add-ons. But then again, back in those days they knew how to build boats better.

If Ole Evinrude had invented a fin, they would probably all have them now. But since the invention came from outside the industry, and is covered by enough patents, I believe that's the only reason they don't come standard. Besides, its not cool to admit that somebody else made your product better.

 

[sickwilly]

Re: Hydrofoil Stabilizer

All hale Jim, all hale Jim -- he has data!

Jim, did you ever try and do a study of how the boats turn?

Lastly, to clarify, your stingray has both tabs and a foil, correct?

 

[guy74]

Re: Hydrofoil Stabilizer

I run a Sea Sport hydrofoil on my 15ft Trihull. It really helps when pulling a skier up. Without it, pulling from the plylon, the bow rise was terrible, with the hydofoil it just takes off. It won't deepwater start a salom skier without it. I took it off once to see if it made any difference in top speed, ran 34mph on the gps both ways. Just my $.02