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

This would be fun to watch. Assuming you arent in a heavy current, the bow
will be facing the wind on a moring. Run up a spinaker in those conditions
and you'll have a blast. The spinnaker will foul against the mast and
spreader and possibly tear.

"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

I agree, but my question was, is it possible under any combination of sail
for the boat to turn aft to wind while secured to a mooring. This is the
crux of my question. We do not want the boat to do so, but my friend feels
that it is possible and could be a hazard to other boats. I feel that it is
a physical impossibility for this to occur.


"truebs" wrote in message
...
This would be fun to watch. Assuming you arent in a heavy current, the
bow
will be facing the wind on a moring. Run up a spinaker in those
conditions
and you'll have a blast. The spinnaker will foul against the mast and
spreader and possibly tear.

"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

On Sun, 4 Jul 2004 17:40:08 -0300, something compelled "Blorgad"
, to say:

I agree, but my question was, is it possible under any combination of sail
for the boat to turn aft to wind while secured to a mooring.

If secured at the bow, no.

"Steve Daniels, Seek of Spam" wrote in message
...
On Sun, 4 Jul 2004 17:40:08 -0300, something compelled "Blorgad"
, to say:

I agree, but my question was, is it possible under any combination of
sail
for the boat to turn aft to wind while secured to a mooring.

If secured at the bow, no.


FWIW.... Ditto!

DP

In article 40e8c292$0$24766$5a62ac22@per-qv1-newsreader-
01.iinet.net.au, "d parker" says...


"Steve Daniels, Seek of Spam" wrote in message
...
On Sun, 4 Jul 2004 17:40:08 -0300, something compelled "Blorgad"
, to say:

I agree, but my question was, is it possible under any combination of
sail
for the boat to turn aft to wind while secured to a mooring.

If secured at the bow, no.


FWIW.... Ditto!

FWIW ..... Bzzzzzzzzzzzt

Of course it is: tide-rode, strong tide against wind: geez us East
Australian sailors forget about tide g.

John

"John Allan" wrote in message
T...
In article 40e8c292$0$24766$5a62ac22@per-qv1-newsreader-
01.iinet.net.au, "d parker" says...


"Steve Daniels, Seek of Spam" wrote in message
...
On Sun, 4 Jul 2004 17:40:08 -0300, something compelled "Blorgad"
, to say:

I agree, but my question was, is it possible under any combination of
sail
for the boat to turn aft to wind while secured to a mooring.

If secured at the bow, no.


FWIW.... Ditto!

FWIW ..... Bzzzzzzzzzzzt

Of course it is: tide-rode, strong tide against wind: geez us East
Australian sailors forget about tide g.

John

Excellent point, however, would a raised spinnaker, based on where the boat
is held and where the force transfers to the boat, not provide assistance
against that effect and tend (given enough wind) to swing the aft end
leeward once more?

In article ,
says...

"John Allan" wrote in message
T...
In article 40e8c292$0$24766$5a62ac22@per-qv1-newsreader-
01.iinet.net.au, "d parker" says...


"Steve Daniels, Seek of Spam" wrote in message
...
On Sun, 4 Jul 2004 17:40:08 -0300, something compelled "Blorgad"
, to say:

I agree, but my question was, is it possible under any combination of
sail
for the boat to turn aft to wind while secured to a mooring.

If secured at the bow, no.


FWIW.... Ditto!

FWIW ..... Bzzzzzzzzzzzt

Of course it is: tide-rode, strong tide against wind: geez us East
Australian sailors forget about tide g.

John

Excellent point, however, would a raised spinnaker, based on where the boat
is held and where the force transfers to the boat, not provide assistance
against that effect and tend (given enough wind) to swing the aft end
leeward once more?

Yup.

In very light wind (say 2kt) and very strong tide (say 4kt), dead
opposite one another, as long as the boat was on a dead run, boat speed
would be less than tide speed and tide would keep the boat upwind of the
mooring, and the mooring would keep it heading more or less downwind.

If there's enough wind for boatspeed to exceed tide speed the boat will
sail up to the mooring, past the buoy, then the mooring will snub and
pull the bow around to windward (I.e. the force of the spinnaker, being
transmitted through the mast and quarter blocks will pull the boat
downwind, pivoting on the mooring) and the boat will end up pointing more
or less into the wind, with the spinnaker wrapped more or less around the
rigging.

John

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

You will end up tearing the chute.
Cant be done unless some unusual tide/wind condition.

You can moor your boat stern to the wind and put your spinaker up.


"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