hydrofoil?

[jbh1024]

what exactly does a hydrofoil do and how bad will it decrease your top speed?

 

[sickwilly]

Re: hydrofoil?

Mine helps my boat plane faster and does nothing to my top speed.

Without it, with the 23 pitch prop my boat came with, I have to go about 7 MPH more to plane, with it, I can plane around 19 MPH.

 

[rndn]

Re: hydrofoil?

I had one on my Baja and it really was not a noticable drop in the top speed. It did help substantially with getting the boat out of the water, but it did tend to cause the boat to wander a little bit at high speed. I used the SE300 model and overall I was very happy with it. I know just about everyone on here says to use smart tabs instead but I really belive there is a place for the foils.

 

[mpsyamaha]

Re: hydrofoil?

on my 16ft semi v skiff the hydrofoil knocked about 1-1.5 mph off my top speed(gps). in my case it didnt really make the boat plane faster... the boat planes almost instantly regardless. what it did do is keep it on plane at much lower speeds, like less than 15mph. i personally didnt like it, and took it off. i often navigate rough water and i like to be able to keep the bow high at low speed to take a big wave just right. plus it changed the handling for the worse at high speeds.

 

[QC]

Re: hydrofoil?

I can plane my 23 footer at 13 MPH with adjustable tabs. I can also get them completely out of the way under any condition. Waaaaay more expensive than a hydrofoil or smart tabs, but I can have 0% or 100% or anything in between, individually, port or starboard, at any speed . . . I like adjustability and flexibility. My story and I'm stickin' to it

 

[180shabah]

Re: hydrofoil?

on my 16ft semi v skiff the hydrofoil knocked about 1-1.5 mph off my top speed...........plus it changed the handling for the worse at high speeds.

That was my experience also, almost.

I lost over 6MPH using the hydrofoil and it produced enough stern lift at speed that I could not get the bow out of the water, hence the loss of speed.

Bad handling would be an understatement in my case. "Loose stern" and "heavy bow" are a bad combination. I ended up doing a bow plant in an evasive maneuver. The fin came off that afternoon and I haven't looked back.

 

[steelespike]

Re: hydrofoil?

I have had good luck with foils on a 120 hp 18ft Mercruiser Cobia I/O and a 15ft Starcraft NOVA w 50 hp Eviunrude.However to do it over I would do Smart tabs or something similar Excellent factory support,are said to solve slow planing,maintain planing easier,handles better, eliminates no wake speed wander.I would be sure to optimize your setup before installing either one.
motor verticle height and weight distribution.careful trimming.

 

[AZSenza]

Re: hydrofoil?

I had both Hydraulic Trim tabs and a hydrofoil, the trim tabs were the BOMB and my new boats gonna get them too, it wont be getting a foil, my 17' 5.7L powered 4Winns lost 4 mph (GPS) with the foil and it caused the bow to plow at speed, maybe it was the combonation of the tabs and foil but the tabs are worth every penny

 

[kynolan2183]

Re: hydrofoil?

Hydrofoils can be very dangerous. Any damage to the foil on a v bottom boat can cause it to list or roll on take off. In stump infested waters where I fish alot the foil increases your frontal demension and can be caught on stumps at slow speeds. Since F=MA ;the force on my lower unit anti-ventalation plate at 6mph is astounding

Mass of boat and gear 1500 pounds at 8.8 ft/s/s is 13200 pounds of force
(hope my math is right)
Granted the stump gives alot and the boat slows alot and rises up and over but I have seen many broken plates.

If hole shot is the issue then vent holes in the prop help alot.

Kyle

 

[10 FOOT INVADER]

Re: hydrofoil?

On my 10 footer the hydrofoil helped it get up on plane faster. The foil also caused a slight pull a lean and some weird steering problems at high speed. Have smart tabs on it now and will never look back. The foils do work on some boats but smart tabs work on all boats. Just got to mount them right and keep the kids from using them as steps.

 

[Gary H NC]

Re: hydrofoil?

I have had nothing but bad luck with foils,On a 17 ft with a Merc Outboard it was bad handling at higher speeds.On a 19ft with a 4.3 Cobra the boat listed when at speed.Took the foil off and gave it away.
Installed Smart Tabs on the 19 footer and it was perfect.Jumps out of the hole and levels off fast.Best money i ever spent on that boat.
I would love to have some helm adjustable on my 21 footer but the budget has Smart Tabs in the future for it too.