"Roger Long"
wrote:
If you let the boat stop, or try to get it going from a stop such as
casting off a mooring, it can't get going fast enough under main alone
to reach the equilibrium where it will sail itself.


I disagree. I've never ever sailed one that wouldn't "go
fast enough" under main alone. The problem is not top speed,
it's how you try to get the boat to accelerate from stopped.


Wayne.B wrote:
Almost any sloop will sail under main alone if beam reaching or close
reaching. The trick is to not over trim the sails, and get the boat
to the right angle with the wind.

Bingo!
And also to not fight the main with the rudder. When the
mainsail fills, of course it tries to 'weathervane' the boat
head-to-wind, which most people then slam the helm over to
prevent. Result: boat doesn't steer & doesn't accelerate to
sailing speed.


.... When leaving a mooring, or any
other time when stopped head to wind, it is useful to back the
mainsail to windward by pushing on the boom. With proper rudder
control this will cause the boat to back up and fall off to the wind.
At that point you should be able to sheet in just to the point where
the sail is full and begin moving forward. If you can build speed on
a beam reach or close reach, a keel boat should carry enough momentum
to allow a tack. Don't over trim or try to point too high. Timing
and rudder control are critical.


Excellent and very much to the point IMHO. It's an unusual
sailing skill, and somewhat contrary to regular practice;
but the way to do it is to ease out large amounts of
mainsheet and let the sail luff freely until the boat is
pointed to a beam reach. I often ease the main out and pump
the helm to windward to kick the stern up, very counter
intuitive to most sailors but it works well.

Our pudgy little trailerable Hunter 19 would not only sail
pretty well under main alone, but could be coaxed into
making pretty good ground to windward *if* you started out
by building up speed on a beam reach (which means not
fighting the helm) and then slowly pointed up. If you tried
to accelerate on a close reach you just end up in irons.

Some catamarans, and Sunfish, have this problem too.

Fresh Breezes- Doug King