The following instructions outlines the various components required to convert a canoe for sail.
The lateen rig is a sturdy, high performance, yet simple canoe sailing rig. When set up according to these instructions on any canoe with either a rudder or paddle for steering, it may be used by one or two persons for crusing or racing.
Preferably made of fir or spruce, the mast for a 44 sq. ft. lateen rig should be 2" in diameter where it passes through the mast seat or thwart. Length is 8'0" to 8'2". The mast should be tapered to 1 1/2" at the top and reverse-tapered to 1 1/8" to 1 1/4" at the bottom of the mast. The mast should have a slot and sheave for the halyard, allowing the sail to be hoisted and lowered while underway.
Preferably made of fir or spruce, the boom for a 44 sq. ft. lateen rig should be 1 1/4" to 1 1/2" in diameter. Length is 8'6". Boom bail for sheet is attached 42" from the forward end of the boom. The boom is attached to the gaff by means of a brass plate or strapeyes.
Preferably made of fir or spruce, the gaff for a 44 sq. ft. lateen rig should be 1 1/4" to 1 1/2" in diameter. Length is 11' 6". Attach halyard 5'6" from lower end of gaff. The gaff is attached to the boom by means of a brass plate or strapeye.
To attach the boom to the mast, use a brass or wood gooseneck on the port side of the boom fastened about 10" back on the boom, so that the sail extends forward 8" in front of the center of the mast.
One leeboard on the port side is sufficient. For a 44 sq. ft. lateen sail, the leeboard should be 8" to 9" wide and have at least 30" of the board in the water.
The leeboard thwart should be 4" wide and either 3/4", 7/8" or 1" thick depending on the type of wood used. The thwart is attached to the canoe by means of a clamp bar fitted below the inwales, and by using carriage bolts and brass tail nuts. In this way the leeboard is held securely to the canoe but can be easily removed. An Old Town style leeboard bracket should be used and faced with a 1" × 4" × 5 1/2" piece of hardwood.
Usually made of the same type of wood as the mast seat or thwart, the step should be 2" to 2 1/2" wide and the length should span at least four ribs. If the canoe has a keel, the step can be screwed directly into the keel or epoxyed to the canoe.
To steer with a paddle, the canoe should have a strong windward helm. Steering with a rudder requires almost no windward helm.
Steering with a rudder: for long canoes (17'-20'), the mast step should be 34" from the center of the canoe. For a short canoe (12' - 16'), the mast step should be 37" from the center of the canoe. Due to placement of seats or thwarts you might be forced to adjust placement of the step 1" to 2" forward of aft. Loss of performance is negligible. The leeboard thwart should be approximately 8" to 12" forward of the center of the canoe.
Steering with a paddle: the leeboard thwart location should be approximately 26" forward from the center of the canoe. Locate the mast step so that the center of the mast is 24" from the center of the leeboard thwart for a long (17' - 20') canoe, and 28" for a short (12' - 16') canoe. Due to placement of seats of thwarts, you can move the mast 1" to 2" farther forward with negligible performance loss.
Note: Clamp the leeboard thwart in place, sail the canoe and adjust the leeboard thwart back and forth until you get the amount of windward helm you want. This applies to canoes steered with a paddle or a rudder.
Fasten the halyard to the gaff, run it through the top of the mast to a block on the front of the canoe, and then back to a cleat on the bottom of the leeboard thwart. Make sure the halyard is long enough so that the sail can be stowed in the canoe and quickly hoisted.
For paddle steering, attach the sheet line to a thwart or seat in the stern, run it through a block on the end of the boom, through a block on the center of the boom, through a block on the leeboard thwart and back to the sailors hand. It is safest to not cleat the sheet.
For rudder steering, attach the sheet line to the boom by means of a becket. Run the sheet to a double block on the leeboard thwart, back through the becket, back down the double block on the leeboard thwart and to the sailor's hand.