As winds get stronger, and you need to drive down to control the boat, this leech fluttering happens again, and now you cannot come up! Try to ease the tack line to increase the separation and rotate the sail leech away from the wind. This will work for a few more knots of wind but….after that its about now that you may have to take the sail down – or put a pole on, and pull the pole back.
Most cruising downwind sails are set with snuffers, or more recently, furlers.
Most modern snuffers work well, but care must be taken that the sock does not twist when hoisting, and good swivels help here. The snuffer is the correct size when both the tack and clew are free of the snuffer when hoisted. In light airs the sail may need to be held to stop the sail just being lifted up as you try to lift the snuffer ring.
The Asymmetric curlers work very well with their high torque resisting luff ropes allowing the head swivel to rotate, driving the sail to furl from the head down. Furlers work best with a flatter Asymmetric.
Gybing an asymmetric is relatively easy and is one of the advantages of this sail. If flown on a pole, the tack should have a downhaul directly from the tack to the bow as well as a guy. The sail should be wound down to the bow with the downhaul and the pole brought to the deck at the forestay.
The question then is whether to gybe the sail on the outside or inside.
Outside Gybing is where the lazy sheet is lead outside the forestay.
Inside Gybing is where the lazy sheet is between the forestay and the asymmetric’s own luff.
In many boats, without a bowsprit, there is not enough space inside, and outside is the better choice. Only if the wind is light and there’s space, then set for an inside gybe – but remember that the choice has to be made when the sail is rigged, and more difficult to change later (but not impossible).
A Prodder (a short stiff webbing just above the tack of the asymmetric) is now fairly standard and avoids the lazy sheet dropping down over the bow or pole when gybing the sail on the outside.
If you are short handed it is often best to snuff or furl the sail before gybing using the space behind the mainsail where there is less wind.
On a ketch there is often a wonderful choice of downwind sails to choose from. On a reach the mizzen mast allows a mizzen staysail to be set which has an important effect on performance and is comfortable to use as it sets entirely inside the boats deck. In order to gain separation, tack the sail to windward (off the genoa tracks perhaps), and sheet to leeward – off the mizzen boom if possible.