On Sat, 18 Dec 2004 11:01:15 -0500, MikeG
wrote:

In article 1103384689.d0185e76b5ed39533aed94649c4268d6@teran ews,
says...
If the prop you have now is the one that was spec'd as OEM, you're not
likely to see dramatic differences by changing pitch or diameter or
number of blades. You indicate you are getting full RPMs -5500- with
your present prop. Changing prop pitch will change that.

There are devices you can bolt onto your lower unit that may give you
the ability to plane the boat at a lower speed...a 20 mph minimum
planing speed seems awfully high to me, but I'm not familiar with your
boat. I have a 25' boat that weighs 3+ tons and it planes at around 17 mph.

A four-blader will give you some additional stern lift.


The planning speed thing was what was bothering me also. It's the main
reason I got to thinking about re propping.

The present prop is in pretty sad shape. I'm hoping that even without
changing anything a new prop of the same spec's will show an improvement
in that area.

We went through this a couple of weeks ago, only we were discussing
wakes.

The question I have is why do you need to have a planing speed of 17
mph. Efficiency is really a function of more than just planing the
boat. It's more a function of hull style, engine rpm, prop size, etc.
Unless you have direct injection, you aren't going to gain much in GPH
if that is what you are after.

A four blade will give you better take off, certainly, but will it
help maintain a 17 mph planing speed? I don't think so.

Later,

Tom - whose first guests are arriving and will be back later - much
later. :)