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-   -   2003 35 Ex prop help (https://www.offshoreonly.com/forums/fountain/267949-2003-35-ex-prop-help.html)

endeavor1 12-31-2011 02:06 AM


Originally Posted by bob_t (Post 3582496)
78 is right in the average range for that boat/engine combo. Do you know if the props had been reworked or possibly had the diameter cut back some? That could explain being marked 32P with 1.5 ratio and running 78 mph. Our twin step 35 Lightning with 500 EFI's ran labbed 30P Bravo 1's props through 1.5 ratio Bravo XZ drives, but it was right at 86-87 mph (gps on a lake at ~600 ft elevation) on the rev limiters. :D

I think you are on to someting here. 32's on a 1.5 would be way to much unless they were cut down IMO.

skidolof 12-31-2011 06:37 AM

How does the boat accelrate with the 1.65s vs the 1.50?

Finney 01-02-2012 07:11 PM

I stand Corrected my Donzi has 1.5 the fountain does have 1.65 I apologize for my ignorance , but even with 1.65 my prop slip is @ 18 percent which still seems a little high?

endeavor1 01-02-2012 08:39 PM


Originally Posted by Finney (Post 3584061)
I stand Corrected my Donzi has 1.5 the fountain does have 1.65 I apologize for my ignorance , but even with 1.65 my prop slip is @ 18 percent which still seems a little high?

Understandable. Per the performance report on my friends, it ran just a tick better with the five blades.

My 46 Black Thunder with five blades ran 18% slip, look at the comparable boats with same or similar power and check their top speed, gear ratio, prop pitch and i think you will find your boat is about on for being factory. The gentleman from the Fountain factory are no slouches IMO. :coolcowboy:

bob_t 01-03-2012 06:36 PM


Originally Posted by Finney (Post 3584061)
I stand Corrected my Donzi has 1.5 the fountain does have 1.65 I apologize for my ignorance , but even with 1.65 my prop slip is @ 18 percent which still seems a little high?

A lot of times you can compensate for too much prop by trimming the drives further out. That will make your slip percentage go up, increase your rpms, but it usually hurts your top speed. What number are you setting for trim at WOT? Also, need to know what number is neutral trim (drive level with boat bottom). With the higher X dimensions Fountain runs, you shouldn't need as much trim. One of the benefits of higher X is that it puts more of the thrust in straight line with the hull with a flatter running boat. Just a thought ...

Fountain Perf. 01-04-2012 08:42 PM

Plenty of Good Advice
 
Do you have your performance report?

I am not sure where you keep the boat but if you are close you can bring the boat to us and we can work with you to dial it in.

We will also be happy to share a few high performance driving tips along the way.


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