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<DIV><FONT face=Arial size=2>Scott,I have a Westerbeke M3 20B with 2:1
reduction.At 2500 engine rpm I get 5knots with a 12x9 3blade machine pitch
prop.This prop allows the engine to go to max 3500rpm if I push it.At 2500 rpm
the engine is at max torque but only putting out 15hp.I think what you need to
know is the h.p. the A4 develops over its rpm range with a transmission
reduction.Have a look at <A
href="http://www.westerbeke.com">www.westerbeke.com</A> >diesel
engines>technical for the M3 20B.There is a useful little graph showing the
relationships between rpm,torque,hp and fuel consumption.This is the sort of
information you need before getting into expense."The Propellor Handbook" by
Dave Gerr gives a lot of useful information and although some of it is very
technical the formulae are interesting</FONT></DIV>
<DIV><FONT face=Arial size=2>Peter Amos</FONT></DIV>
<DIV><FONT face=Arial size=2>Tait Tait #478</FONT></DIV></BODY></HTML>