Marty Browne wrote:

Hi All,
I thought the original question pertained to mainsail trim.
Well, Here I go---jumping into the shark tank....
try putting telltales on the mailsail leech. Position one at each batten
pocket.

Not the best place for them IMHO. The battens will maximize turbulence coming
off the leach.

As a general rule of thumb, if you have the all telltales
streaming, your mainsail is probably OK for the conditions.

Nope. If your telltales are streaming, you could be OK or your sail could be
flapping uselessly. Think about it. If you are on a beat, then you definitely
want to see the leach telltales get pulled in behind the sail
occasionally.... how often and for how long is different for different boats.

Perhaps
better than OK. keeping the top batten telltale streaming is often
difficult. Keeping that one streaming, off the wind, often requires lots
of backstay and boomvang tweaking in order to find the "just right shape.


Tweaking the backstay off the wind doesn't sound good IMHO. Boom vang yes.
And remember that you want the leach ribbons working together; not absolutely
streaming at the top or whatever. That is the best way to judge the twist of
the sail, getting the leach ribbons working together. Sometimes you want the
upper one pulling back just a little more than the lower one.

If the leach ribbons don't pull back once in a while, then it's entirely
possible that the sail is not generating any differential flow between the
windward & leeward sides, and thus producing no power. Max differential
pressure across the sail will pull the leach telltale back behind the sail,
this is max power but it may not be working to propel the boat.

Fresh Breezes
Doug King