"DSK" wrote in message
.. .
Gilligan wrote:
The USS Constitution demonstrated that in light air, the speed of the
ship could be increased by spraying water on the sails.

Documented he

http://www.history.navy.mil/photos/e...a/const-es.htm


Sure. Well known and oft-practiced trick for getting a bit of speed out of
natural fabric sails. I don't know when it was first used, possibly back
when they started weaving cloth strong enough that sails no longer needed
leather reinforcing strips (the Viking Age tape-drive laminate).


I do it regularly in strong winds. Even get the tippy top part of the sail
wet.








Think of this. The sail has the most power delivered to it when the
residual wind velocity is zero after interacting with the sail.


I think that's a mistaken assumption. The sail has the most power
delivered to it when it is developing max differential pressure
theoretically possible for it's density & initial velocity.


The maximum pressure differential occurs for any given windspeed when the
airspeed on the low pressure side of the sail is zero.

No, the maximum differential pressure possible is when the LP side is a
vacuum. Velocity can produce pressures lower than ambient; air that is
sitting still cannot.

You're right.



.... If the velocity on the "low pressure side" equals the velocity on
the high pressure side there is no lift.


C'mon, you're not thinking in vectors! What if that velocity is equal to,
or faster, than on the HP side and in a different direction?

Can't it act only normal to the surface?



DSK