I must apologies to Neal - when ran the added 2000 pounds through SailCalcPro the SA/disp
came out to 11.83, still lower than any production boat I know of. I've certainly seen
some loaded to where they are in single digits. Neal would have to add over 3000 pounds
to get down to what I quoted - but that's possible too - it would mean being about 4.5
inches below her lines.

Running the VPP number for +2000:
At 14 kts, the sail still generates 6 hp, but this is now 1375 pounds/hp, instead of 1000.
This will push him at .95 of sqrt(LWL), which with the increased waterline, which comes
out to 4.75 knots. The original calculation yielded 4.9 knots, so there is a net loss.
In lighter wind he has more wetted surface, and although his ultimate hull speed may be
higher, he has to carry full sail in well over 20 knots to get there. The 20 knot
prediction leaves him at 1.2 sqrt(LWL), or 6 knots, instead of 6.3.

One might claim that this is a small penalty to pay for carrying your life's possessions
with you. And I'm not sure I'd like know what my boat weighed the day we left for the
trip. But its pretty clear that increasing the LWL by loading the boat does not make it
faster.

One more thought - I think Neal gained LWL by submersing the aft section, just forward of
the transom. I haven't been able to find a design drawing to confirm this - is it
possible Tripp had them all destroyed? If this is the cause for the seeming discrepancy,
then this extra waterline would have become available whenever he went fast enough to
generate a stern wave. This is a common design trick - the overhangs create additional
effective waterline as the wave making resistance goes up. So by loading the boat, one
does not actually gain LWL, one gains wetted surface and more weight to pull around.

I hope a few people have appreciated this exercise at Neal's expense. I always wanted to
run these calculations and compare them to real life. My primary source was Dave Gerr's
"The Nature of Boats." If I can find a more formulaic expression of this, I might make a
little calculator, like SailCalcPro.


--
-jeff www.sv-loki.com
"I wish to have no connection with any ship that does not sail fast; for I intend to go in
harms way." - John Paul Jones


"CANDChelp" wrote in message
...
8200, which drops your SA/disp down to a dismal 10.7! While your ultimate
speed may be
faster, your medium air performance is now pathetic.

Slam.
That was harsh, Jeff.

RB