jeffies, if folding/feathering/kinda twisting props increased performance by
your claimed 10% ALL new boats would have them installed at the factory.

duh.

From: "Jeff Morris"
Date: 9/5/2004 10:55 AM Eastern Daylight Time
Message-id:

Time for the meds again, jaxie. Your reading comprehension is failing. I
made
no claim of the Westsail, I said "At the low RPMs many boats use to go 5
knots,
they only use 10 to 12 hp to go forward." Are you claiming that a Westsail
is
representative of "many boats"?

If fact, I already said several times that I didn't think a low drag prop
would
help a Westsail that much, but they could be of value to many other boats.
You've been claiming that they are useless for any boat other than a high
performance racer. Since you lost that argument, you're now backpedaling and
misrepresenting my comments. Typical lying from cowardly jaxie.

But, since you brought it up, how much power does a Westsail actually use?
At
5 knots, that is a "Speed to Length" ratio of 0.95 (where the 7 knot hull
speed
would be 1.34). To achieve that speed, a displacement boat will have 1400
pounds per HP. At 20,000 pounds, the Westsail uses about 14.2 HP. A bit
higher than the "10 to 12" I mentioned for "many boats," but most 32 footers
don't weigh anywhere near 10 tons. How much wind is needed to generate 14
hp
on a Westsail? With 650 square feet of sail, assuming 0.02 HP/sq.ft. at 14
knots wind, this is 13 HP; so it looks like about 15 to 16 knots of wind is
needed to get a Westsail up to 5 knots.





"JAXAshby" wrote in message
...
jeffies, **you** claimed it only takes 10 or 12 hp to push a Westsail 32 at
five knots. remember? nah, I am sure you don't remember anything from
more
than 7 hours ago.

From: "Jeff Morris"
Date: 9/4/2004 11:11 PM Eastern Daylight Time
Message-id:

"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