Not sure

ffountain

Seaman Apprentice
Joined
Mar 7, 2008
Messages
42
Not sure if I'm in the right forum (I'm sure you'll let me know). i have a 1988 Javlin 378 F/S w/Johnson GT 150. The prop I am using at this time is a 3 blade aluminum 14 1/4 x 21. I also have a Stainless 3 blade 14 1/2 x 26 that came with the boat. I'm having trouble getting my boat to plane out at slower speeds such as for pulling a knee boarder. Which prop would be better?
Any other suggestions would be appreciated.:confused:
 

Dhadley

Supreme Mariner
Joined
Feb 4, 2001
Messages
16,978
Re: Not sure

I'd think the 26 would be a bit stiff without the extra load of a water toy. Especially a knee board.
 

Randybeall

Petty Officer 1st Class
Joined
May 2, 2008
Messages
319
Re: Not sure

Sounds like a boat set up to run 50 mph being used for tow boat duty. With out rpm numbers best guess would be to use the 21 or even go down to a 19. You will loose some top end but be able to get the knee board in the easy to control range. Try to get us some engin rpm numbers particurlarly wide open throttle run and you can get a more accurate response.
 

towtruck1

Seaman
Joined
Jul 11, 2008
Messages
67
Re: Not sure

This is a hydrofoil (water-wing). It is literally a wing that goes through water, providing 'lift' at the back end, and helping get the bow down and the stern up faster.

However:
There are drawbacks. Some people say it negatively effects the way a boat handles, particularly in turns. Also, the hydrofoil takes energy that should be used to make the boat go forward, and uses it to keep the back up. Poor use of energy. So while it helps hole shot, it will lower top speed. In your case, that may not bee so bad. Some say it puts too much stress on the engine.

Bottom line:
It works, but with lots of drawbacks. I am pretty sure that the general consensus around here is that the Smart Tabs do a much better job of helping get and stay on plane, w/o lowering top speed, etc. Yeah they are more expensive and they don't work on some hulls (like if you have a swim step etc.), but in general, they are much better.

Final thought:
As long as you've got the hydrofoil already, and the holes are already drilled int the anti-cav plate, it probably couldn't hurt to try it out. If you do, make your turns wide at first, and then progressively tighter to check the effect in turns.

Hope this Helps
Towtruck
 
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