flying a spinnaker at the mooring is not a good idea, even in light winds as
I don't see how the boat would turn downwind. your suggestion that the
spinnaker would be damaged is right. there would be little point. that said,
you could tie the stern to the mooring bridles, and then hoist the
spinnaker. that would have the boat facing downwind before you start, and
better simulate the boat under sail. be ready though as the boat will yaw
somewhat and you will have to adjust the spinnaker. using two bridles port
and starboard would reduce this. I have seen a spinnaker flying at the dock
in the same fashion. only do this in light winds.

it would be a better learning experience to have someone on board who knows
what their doing, and fly the spinnaker under sail, as there is more to it
than just hoisting it up there.

to help settle the argument, any force the spinnaker would develop would
pull against the mooring, which would normally be attached at the bow, and
thus keep the boat facing the wind. it would not be like hoisting the
mainsail for example, as this sail will develop lift, driving the boat
upwind, at least until it ran out of mooring, at which point it would again
be forced to turn to the wind.

Norm

"Blorgad" wrote in message
...
My friend and I are having a disagreement regarding the behaviour of
sailboats on a mooring. We both have limited sailing experience, although
he
has a fair amount more than I. We were discussing running up a spinnaker
at
mooring in calm air, just to practice putting it up. We eventually
concluded that this wasn't practical, but the argument came in as to our
our
different conclusions as to why it would not be. I felt that there would
be
no point to put it up, as it would just get blown into the rigging and not
really tell us anything and possibly get torn. He was of the opinion that
somehow the spinnaker could push the boat to one side, fill and turn the
boat around. Initially he said it would go right upwind of the mooring,
then reduced his claim to say that it would turn around at the point where
it was attached to the line at the bow.

I am of the opinion that this is physically impossible and that under no
combination of sail at a mooring could the boat turn around so that the
aft
was upwind. I am of the opinion that you could get the boat to swing to
one
side or the other a bit by backing the jib, but you could still never turn
the boat around.

I would gratefully accept as many informed opinions on this from a sailing
or physics point of view.

Fair winds,
Miles