Wally, you certainly are not the sharpest tool in the shed!

Your contention that the shelf 'sags' when the outhaul
is tensioned does not occur in real life. I guess you have
never sailed a yacht that uses a proper shelf-footed sail.

More on why your comments make little or no sense.

When the outhaul is tensioned so the shelf foot is collapsed
then what would be the foot (if the shelf were suddenly removed)
becomes taut, as does the shelf itself, since the shelf is not removed
in fact but still attached to the taut foot. Therefore, it follows
that the shelf still exerts a downward force on the taut foot
(the part of the sail the shelf is attached to). This imparted force
is along the entire length of the boom so the sail is flattened just
as if you were looking at the luff of a mainsail that is stretched along
the length of a bent mast under tension from an hydraulic backstay
tensioner. After all, does not the luff of a mainsail mimic a shelf
foot in that it is cupped for aerodynamics?

What has happened to the minds of young people these days
in that they cannot envision simple concepts in their heads?
That which is second-nature to the likes of myself and
Gilligan seems foreign to the Television-addicted generation
of today, a generation totally bereft of imagination.

CN


"Wally" wrote in message .uk...
Capt. Neal® wrote:

... but when the outhaul is tensioned, the shelf foot closes and the
bolt rope in the boom tends to flatten the sail.

Once again, a self-proclaimed old salt embarrasses himself by inviting a
sweet, innocent, fresh-faced n00b to provide an elementary lecture in the
dynamics of the outhaul on a shelf-footed main...

The sail is flattened under outhaul tension due to the direct pull between
tack and clew. When thus tensioned, the surplus material in the shelf foot
sags. Since the shelf is sagging, it imparts no downward pull on the main -
it is slack cloth between the bolt rope and the sail, proper.


--
Wally
www.artbywally.com/FiatPandaRally/index.htm
www.wally.myby.co.uk