We got the gaff sail finished, it came out to around 41 square feet. Then Skipper took it out for a test float to check balance, figure out control lines and get a general look at how the rig sets.
But first we had to make a sail, mast step, boom and gaff.
We had scaled a sail from John Leathers book Gaff Rig to work on this mast and on this canoe's gunwale height, with 16 inches of step at the bottom and 30 inches of topmast to set a peak halyard. Leather's suggested ratios for a sail were Luff 1.0, Head 0.833, Leech 1.73 and Foot 1.02, with a 30 degree rise at the head of the sail and 6 degrees at the tack.
Throwing out a lot of terms here, here is a diagram of gaff sail nomenclature for David Nichol's book The Working Guide to Traditional Small-Boat Sails.
Laid out our sail dimensions. 6 foot luff, 5 foot head, 10' 6" foot leech and 6' 4" foot.
Oriented the cloth so that the cloth panel seams, the panels are about 30 inches wide, were oriented along the leech, to give the sail a vertical panel cut. Added a 1 1/4 inch seam allowance along the foot, luff and head with blue tape. Cut out a sail from a painter's drop cloth, then did a double tuck on the seam to give the sail a 3/4 inch seam all the way around. The fabric unravels easily so go slow. The medium duty Genome did okay on the first batch of stitching, and the Sailrite LSZ-1 had no problems working the fabric. We also cut double reinforcing panels for the corners.
We put in Grommets, #4 for the head, tack and clew and #1 for the luff and head. Check out our post on Spur Grommet Installation.
The canoe had gunwale holes for the thwart and fittings in the bilge for a mast step and sheet block for a 45 sf gunter rig. We are using those fittings as locations for our gaff rig. Worked on the thwart first, enlarged the factory gunwale holes to 1/4 inch, because we bought 1/4 inch carriage bolts. Smaller carriage bolts would work too and skip the drill.
we had an old mast similar in size to a Sunfish mast, 2 1/4 inch diameter and just over 10 feet long. After we cut the thwart 5 inches long and fit it to the gunwales we cut a 2 1/2 inch hole for the mast.
We used the pergola to hold up the mast while we fit the step.
We cut a rectangle in the bottom board to fit around the factory step in the bilge, and mad a round step to fit inside the mast. We tried this basic setup first but the amst could move the step side to side.
Rounded the edges of the thwart to prevent bumps.
Ergonomic testing.
Roll tacking!
Sheet block attached to factory fitting in the bilge.
We added the V braces to prevent lateral movement of the step.
We cut out some 1x pine jaws for the boom and the gaff, cut a slot to fit the closet rod and screwed them into place. We drilled pilot holes to prevent splits and then set silicone bronze wood screws to hold the boom and gaff. We also put screws in cross grain to prevent splits down by the jaws. Drilled 1/4 inch holes to attach the tack and the downhaul, used a Sunfish sheet snap and 1/8th inch line. Also drilled holes for parrel beads.
We attached some field expedient halyards, put on outhauls through 1/4 inch bee holes and trimmed the boom and gaff to length. Left a little extra for sail stretch.
Skipper paddled, did some roll tacks and gybed. Had a blast in the Grumman Cat Canoe
Log of SCOUT.
Thanks for your Blog Posts. I am really enjoying it.
ReplyDeleteYou're welcome. That simple rig was the best. As we progresses into adding more sticks and strings we veered further and further away from the simplicity of the canoe. We've recently acquired a lateen rig and gunter rig designed by Grumman and plan to try those out in the future. Stay tuned! Clark and Skipper
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