On Aug 16, 6:08*pm, "Ken S. Tucker" wrote:
On Aug 16, 2:27 pm, Mxsmanic wrote:

Ken S. Tucker writes:
Ok, have you ever been in a sail boat?

No.

Well you must try it.
Your doing a tack with the sail fully stable suckin'
energy from the wind, cuttin' water and bouncin'
waves off the starboards, that's the sound you hear.

Next, you reverse tact and the sail flutters (stalls)
until re-acquistion of stability going in nearly the
opposite direction and you're still heading into the
wind, so the net motion is into the wind. Every pilot
should do that. I was on trapeze, *with a good fat old
captain on the til, and me being a skinny lively bitch
loved jumped to either side of the boat, pulling the
sail to max the energy out of the wind.
Regards
Ken
PS: Read about it.

On our boat we put the crew to the windward side to keep the mast more
vertical. We adjust the sail by pulling on the correct strings, and
it depends on the tack as to which is the lee rail going awash.

As for stalling a sail -- on a beat there's lots of flow separation on
the low pressure side of the sail, but it continues to drive the boat.
The luffing at the trailing edge just means there's marginal flow
separation there, not at the leading edge. If you want to really see a
sail stall, do a jibe, not a come about. If you don't duck you'll
learn soon enough why the part sweeping across the cockpit is called a
boom.