"JAXAshby" wrote in message
...
jeffies, a boat under sail has one hell of a lot more drag than a boat
motoring
in a flat calm.

And how is this relevant to anything?



also, keep in mind that the boat under discussion is a Westsail 32, a boat
usually having a minimum of 30 hp installed, and often 40+ hp.

A Westsail 32 with a 10 to 12 hp engine installed is unmarketable. One would
need one hell of a lot patience to wait for wind and tide before setting off.

Are you claiming that an aux engine is always run at an rpm that produces its
full rated power? Most boaters understand that a diesel might only produce half
its rated output at cruise speed. For example, a Yanmar 3YM is rated at 29 HP
only delivers about 14 to the prop at 2800 rpm.

Although the OP has a Westsail, he asked what other boaters have experienced, so
the discussion is about all boats. As I said elsewhere, I think the Westsail
would benefit less than other boats from a low drag prop.






keep in mind that props don't drag all that much anyway. according to the
MIT
data, even a fixed 3 blade only pulled 170# on a boat at 5 knots, or about
the
equivelent of 2-1/2 hp.


That's not much drag??? That's roughly the drag from a 25 knot breeze!
Are
you saying that this would have no affect on boat speed?

Are you claiming that a having a 2.5 hp engine pulling backwards would have
little affect on speed? At the low RPMs many boats use to go 5 knots, they
only
use 10 to 12 hp to go forward