What size is your boat? I have a 1986, 268 Sundancer (350, Alpha1 as well)
and its dry weight (if I recall correctly) is around 6800lbs. I used to
have an aluminum prop, but went to a 15x15 Stainless to get it out of the
hole better. My minimun planing speed is agout 20mph at 3400-3500 rpm (2
people and around 1/2 tank of gas). By the way my fuel tank is rated 100US
gallons. I too have a paddle wheel speed sensor and is very close to a
friends GPS.

The original aluminum prop had a 17 pitch and was even worse getting it out
of the hole. Top end then and now is still about 28-30mph at 4200 rpm.

You can see bits of our boat in some pictures on the company site where the
S Hooks are on display (www.ripnet.com/vtf/prod03.htm).
Mark


"Joseph Friess" wrote in message
.. .
I have a 1986 Searay Sundancer with a Mercruiser 350, 260HP, Alpha 1
sterndrive and boat weight of about 4700 lbs. I would be interested in the
prop size from any other owners of this size boat and engine.
Specifically,
what kind of speed to do get at 3000 rpm or 3500 rpm for a given prop
size.

With 2 adults, full tank of gas (70Gal) and water (30gal), I get around
19-21 mph at 3500 rpm with the outdrive and trim tabs optimized.This seems
a
bit slow for this rpm. I have a paddle wheel speedometer and GPS readings
and they are close, depending on the wind.

I don't know my prop size now, but will be getting it this week, weather
permitting. Any help or suggestions would be appreciated.