# hydrofoil for more speed?



## mtnwkr (Feb 6, 2011)

I just bought a 13.5' welded Gregor with an early 80's 10hp honda 4strk. Out on the lake today with just me, a 60lb dog, trolling motor, battery and gear I was moving at 17.5mph and it took probably 6-8 seconds to get on plane. I'm wondering about the advantages of a small hydrofoil. I've read they will help you get on plane quicker but what about top speed? Will it help or hurt? I dont want this to be a dog with two guys, gear and crab pots on board. I was looking at the walmart junior hydrofoil which claims to increase top speed.
Any other ideas to increase top speed? The boat is rated for 25hp but this little honda runs so good I plan to keep it even if it is a bit slow.


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## jdd5p (Feb 7, 2011)

I have a 14 foot v-hull with a 25hp johnson I bought this summer. The previous owner had one of those installed. I actually took it off yesterday as an experiment. I gained 2 mph top speed (from 25 to 27). It did get on plane easier when it was installed. I say easier, but not necessarily faster. With it installed I could just hit the throttle wide open and be on plane in about 5-6 seconds. With it off if I hit the throttle too hard before its on plane the bow rises up so high I can't see. Once it is on plane it works great though and it feels like it accelerates faster. Turning is definently easier too. Maybe your results will vary, but I will not be putting mine back on.


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## Whoopbass (Feb 7, 2011)

A hydrofoil will not give you more speed. About all they do is plane a boat out quicker and usually handling will suffer.
There probably isn't anything economically you can do to that motor to get more speed out of it. 
Adjust the height of the motor in each slot until you find which position is the fastest for your normal load. 
A lower pitch prop will help you get out of the hole.
17.5 mph isn't bad for that motor.


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## mtnwkr (Feb 7, 2011)

Thanks for the suggestion Whoopbass. I'll try it with the motor in different position to see if I gain any speed. I've also read about raising the motor on the transom with a jack plate helping speed. Any thoughts on this?


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## crazymanme2 (Feb 7, 2011)

You can raise your motor so the cavitation plate is even or as much as 1" above bottom of your boat.Too high & your motor will blow out or you won't pump water because water intake is too high.
The speed your seeing now isn't too bad.


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## Whoopbass (Feb 7, 2011)

I have a jackplate and it doesn't seem to do anything.


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## nathanielrthomas (Feb 7, 2011)

I know this is off subject, but that is a good lookin old honda, and a beautiful dog. Havent heard anything good about the hydrafoil things. Most people Ive talked to complain about them. 

On another note, I spent too much money trying to get my 9.9 to run faster, but the plain truth is its gonna be slow with two people in the boat. I got my 1448 up to 25mph with a 9.9 nissan through putting on a jack plate, throttle advance cam from a 15hp, and boyensen reeds. The jack plate did help about 2mph. But when I had two people in the boat plus gear, it cut it down to 15-17mph. Ive found the most economical way to get more speed is to buy a bigger motor. I have a 25hp now, and it runs great with 2 or 3 people in the boat, and it'll really scoot.


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## slabdaddy (Feb 7, 2011)

I agree with Wh-Bass; speed is good for that little motor! 8)


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## Pappy (Feb 8, 2011)

Although the picture is a little far away it looks like your trim pin is out in the second hole? If so put it in the hole closest to the transom and your planing times should become acceptable. All hydrofoils will add parasitic drag and will reduce overall speed if they are in the water while on plane. They will, however, reduce or eliminate porpoising (bow hopping up and down) in many hulls.


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## Troutman3000 (Feb 8, 2011)

I put a hydrofoil on my 40hp Mariner and I didnt lose any speed. What it did was totally eliminate the porpoising that I was having trouble with when I was riding alone. I did notice that it has made me get less fuel efficiency though. However, when I am loading with my bait tank and a passenger the foil cause me to plow right into wakes and waves. It takes away the boats ability to rise up and deal with unstable waters. It also makes steering a little tougher, but I think it stabilizes the boat and allows me to stay on plane at lower speeds. 

That being said I wouldnt take it off because the benefits out weigh the negatives imo. 

But I may try running without them now that I have two batteries up front to help with the weight distribution. Would the holes in the cavitron plate cause any ill-effects on the motors performance?


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## Ictalurus (Feb 8, 2011)

Troutman3000 said:


> Would the holes in the cavitron plate cause any ill-effects on the motors performance?



Put some duct tape on the bottom of your cavitation plate and fill the holes w/ JB weld. They close up nice.


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## Troutman3000 (Feb 8, 2011)

Ictalurus said:


> Troutman3000 said:
> 
> 
> > Would the holes in the cavitron plate cause any ill-effects on the motors performance?
> ...




Cool.....


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## Flat Bottom (Feb 8, 2011)

Ictalurus said:


> Troutman3000 said:
> 
> 
> > Would the holes in the cavitron plate cause any ill-effects on the motors performance?
> ...




ditto, i love jb weld...


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## rusty.hook (Feb 12, 2011)

If you put the whales tail/hydrafoil on and it caused your boat to be harder turning then your cavation plate that your whales tail is bolted to, is probly too low in the water. So when you try to turn one way or the other, the water forces it down and want let you turn. I had one on my boat and my mechanic looked it and said the cavatation plate was about 1" below the boat bottom therefore that was the problem. I have since taken it off and now have no problems when trying to turn. Gets out of the hole slower now though. I will put on a jack plate later.


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