What's the best prop pitch?

[kchunk]

Anyone have a suggestion for a replacement prop. My 23/3 has the Tohatsu 9.9 2-stoke. I have no idea if the prop on it is original or what the pitch of it is. 4th of July we were heading out for fireworks and the water has been pretty skinny at the dock. To get out of the slip I left the rudder up just a pinch. Well, need I say it? I introduced the rudder to the spinning prop with the prop in reverse. Wasn't too bad, and I proceeded as if I meant to do that and everything operated normal.

Anyway, we're heading to the Keys next week and the last thing I need is a spun prop with no spare. Has anyone replaced the prop on their 23? What pitch did you go with? Is there a rule of thumb for sailboats? From the Tohatsu website it looks like they recommend a 9.2 diameter 7.8 or 6.9 pitch 3-blade.

How's that sound? Any input?

--Greg

[LConrad]

I have the same setup. It came with a 7.5 inch pitch which seemed too long.  The engine labored more than I liked and boat speed at idle was pretty fast.

PropCalc suggested 8.6 Diameter, 5.5 Pitch for a three blade and 8.1 D and 5.4 P at 5,700 RPM using my assumptions.  I chose the 8.7 D, 5P four blade 3B2W645110 high thrust and am happy with it.  The short pitch allowed the boat to go slower at idle speed - better for me.  Acceleration is better.  RPMs are a little high wide open, but there is little reason to do that.  9.8 HP is more than we need for the hull speed of the boat, so trying to  go faster takes lots of power.  I back off a little and don't see much difference in boat speed.  I suspect it would be very helpful pushing into a heavy wind. 

Another good option looks like the 3B2W645126 8D 6P.

[LConrad]

I did a full throttle check today.  Prop-calc said max speed is 7.1 MPH and that is what the GPS reported as well. Now if we only had a tachometer on 9.8 Hp outboards!