Mike,

I have a 1985 21 ft Sea Ray 210C (cuddy cabin) with the OMC drive. Although
the boat already had hydraulic trim tabs I found that I got a significant
improvement in lowering the planning speed by adding one of those trim fins
to the lower unit. It is much more effective at getting the bow down and the
boat on plane than anything else that I've tried. I would suggest that you
invest in one of these fins first. After you try it I'm sure that you will
just replace the prop without changing the pitch.

--
Charley


"MikeG" wrote in message
ews.com...

The basics.

I've got a 1985 seaway V hull that weighs in around 2k. It is powered by
an OMC 1.6 L seadrive. Full throttle range is listed as 4500 to 5500 RPM
and has a 13 1/4 X 17 three bladed prop on it. The prop's condition is
such that it has to be replaced come spring. I will, at some point, have
the existing one repaired and use it for a spare.

I fish. I don't foresee towing or pulling anything, skiers, float toys,
etc, behind the boat. While high speed is nice my main interest is
efficiency. Especially in fuel consumption and range.

As it sits the boat runs about 30MPH at 5500 RPM and falls off the plane
right around 20 MPH at 4600RPM. These figures may, considering the
condition of the present prop, improve slightly with a new prop of the
same size. I don't know that for sure though.

Looking at the figures it appears to me that, though I would like to be
able to maintain the plane down to about 17 MPH, this is about as good
as it gets for the boat/engine combination.

Is it? Would I be able to realize something more efficient with a
different prop, and, more importantly for making my decision, What
effects be if I were to change to a four blade and or change the pitch,
maybe even change the size if that is possible? Stainless steel is not
an option. I fish the rocky coast around Boston harbor and would rather
replace a prop rather then the lower end should I get stupid.

PLEASE, just comments on the matter at hand and try not to end up in an
infantile name calling contest of no value.

Thank you





--
MikeG
Heirloom Woods
www.heirloom-woods.net