Aug 20, 2002
I have used the mule on my ketch and still have the sail and rigging.
I found that it is a useful sail in wind under 10 knots and forward of the beam. In very light air I have seen the mule add a whole knot of speed, from 2 knots to 3 knots.
My boat tends to develop a lee helm going to windward in light air. The mule eliminates that lee helm, as it is effectivly located behind the center of lateral resistance. It also is high, so gets good wind.
Above 10 knots the sail produces so much weather helm that it is counterproductive.
I attached a block at the head of the mainmast, then led the halyard through that block, to the foot of the mast where I installed a turning block and belayed it to a cleat on the cabin top adjacent to the cockpit. I installed a small length of track on the foreward side of the mizzen mast, the lower end low enough that I could reach it to attach the tack of the mule, the upper end high enough that the tack lined up with the luff along the edge of the backstay when the halyard was taut. A snapshackle on a car on this track secured the tack.
For a mule to be effective, it must have a boom. Without a boom, the sail only provides heel, not propulsion.
I had a boom fabricated from a sailboard boom. The forward end of this boom was shaped into a notch that was able to ride on the backstay.
The sail is held by the halyard, the snapshackle on the mizzen mast, another shackle on the after side of the forward end of the wishboom, and an adjustable outhaul to the after end of the boom. The boom is trimmed by a line running from the head of the mizzen mast. The mizzen staysail halyard works well, and does not interfere with the use of the mizzen staysail as the two sails are used on different points of sail.
Setting and dropping the sail can be a minor problem. After hauling the halyard almost taut, manipulate the lower end of the luff by hand to get the notch of the mule boom to ride on the backstay. It may take some effort.
Dropping the sail is also interesting, as if often occurs when the wind comes up, and the boom gyrates in the air to leeward as it is dropped.
It is a lot of work to do for cruising, but it was a successful racing sail. I have not used it since I installed a radar reflector on the forward side of the mizzen mast which interferes so that the mule cannot tack.
The proper name for the sail is "Main Backstaysail".
If anyone is interested, my sail and boom can be bought. It might not fit your boat as my mizzen mast is 18" higher than when it came from the factory.
Dick Weaver, SWII75K