Offshoreonly.com - Fountain brakeing prop shafts

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- - Fountain brakeing prop shafts (https://www.offshoreonly.com/forums/general-boating-discussion/249889-fountain-brakeing-prop-shafts.html)

Single With Twins

03-23-2011 07:48 AM

both Kelly and Driveguy have said exactly what i was told too from dbl R......I ran the second half of the season with drives at 1.5, max 2 on indicators and did not have any issue, obviously scrubbed speed.

29scarab10

03-23-2011 08:32 AM

What gear ratio are those drives?
Allen

Wahoo ATV

03-23-2011 10:13 AM

when you replace them use the large dia IMCO one piece shaft. We have never broken one of them, but have broken the Merc 2 piece shaft.

Baja555

03-23-2011 10:52 AM

Quote:

Originally Posted by Kelly O (Post 3357332)

Seems like the issue is the drive heights. Fountain gets great speed out of those 525 boats by running drives so high props end up surfacing. I don't think the Maximus is designed to be a surfacing prop.
The only way that 38 could swing a 35P is with high slip numbers due to the high drive height. That is what stresses the props.
Has anyone tried spacing down to lower slip then run a lower pitch prop ? May cost a couple mph top speed but the boat would plane and handle better and quit throwing blades.

I totally agree,, drives and props get a hell of a beating when they surface, especially under power..Thats a problem with a boat that is setup for more top end than it should have.. And thats what fountain does...A normal stepped 38 should nowhere near be trying to swing 35's .. lower the drives and smaller props and have a nice useable boat..

Driveguy

03-23-2011 06:45 PM

Quote:

Originally Posted by Wahoo ATV (Post 3357499)

when you replace them use the large dia IMCO one piece shaft. We have never broken one of them, but have broken the Merc 2 piece shaft.

What the f is a two piece shaft?

Baja555

03-23-2011 07:06 PM

after it breaks ,it's two piece..

mikes280

03-23-2011 07:35 PM

drive is to high that is why it needs all that prop. there is one here that was doing the same thing he lowered the drive with spacers and problem was gone . Only thing is the boat slowed down. If you are gonna play you gotta pay.

BenPerfected

03-23-2011 08:42 PM

I think it is combination of the 5-blade props and drive height. Here is another practical but slower solution. Space down to use the Bravo 1 4-blade props and your problem is likely solved.

BenPerfected

03-23-2011 08:54 PM

...forgot to say, if you are up for the hassel and able to get on plane with B-1's, your top end should be close to the Maximus...maybe off 1-2 MPH. Our testing was in the other direction. We maximized the X with B-1's, and then ran a set of 5-blade Herrings that were 1 pitch less. Close to same RPM but the speed was +2 MPH. We didn't end up using the 5-blades as they created too much stern lift and the boat felt way loose.

A.O. Razor

03-23-2011 09:07 PM

Quote:

Originally Posted by Baja555 (Post 3358013)

after it breaks ,it's two piece..

Good one:D

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