Sunday, January 22, 2012

Making the sails, part II

Today I finished one of the sails (except for batten pockets and reef points), and the other is on its way.  First I cut and glued together (using double-sided seam tape) all the reinforcing patches, each with three layers.  The tack and clew patches are quarter-circles, and so are the patches at the reef-corners (which are actually known as cunninghams, don't ask me why).  The throat patches are obtuse angles, and the peak patches are acute angles.  (See previous post for explanations of the terms).  In all there were 12 three-layer sets, for a total of 36 pieces.  They look like pieces of a nun's wimple, or complicated origami.  In fact they will keep the stress-points of the sails from being ripped by yards, sprits, downhauls, etc.

Half of these were stitched onto the mainsail, with the inner edges turned under.  The bottom edges of the reef corner (cunningham) patches had to be finished with 2-inch sailmaker's tape.  Then the leech and foot were finished by stitching the edge under.  Then the luff and head were finished with 3-inch sailmaker's tape.  You can see the sail after all the stitching in the second photo, taken from the top of the stairs.  My daughter's cat finds the whole sailmaiking scene an endless playground, so she wouldn't budge.  It adds a little scale and human interest to the whole thing, I feel.  You can tell that the sail has curvature built into it: it will not lie flat on the floor.

Then I put in grommets in the six reinforced corners,  and every eight inches along the head (to lace it onto the yard).  The third photo shows some detail of the grommets.  In some places there were so many layers of cloth that it took a lot of pounding with the cylindrical hole cutter to cut through all of them.

So there you have it.  I don't think I'll be able to finish the mizzen sail this weekend, but both should be done before the month is out.

There will be more, you can be sure of that, so keep checking 176inches.


Sunday, January 15, 2012

Making the sails, part I

Sailmaking (and mending) is traditionally a winter activity, and so it is for me.  The only carpentry-related thing I did since the new year was to laminate together two layers of 1X2 lumber for each yard.  The main yard will be 8 feet (2438 mm) and the mizzen 7 foot 4 inches (2235 mm).  I need to round the edges, sand and finish, but that can wait.  Which brings us to the sails.

I ordered my materials from Sailmakers' Supply, including 16 yards of sailcloth, thread, seamstick (2-sided tape to hold seams together while sewing), sailmakers' tape, a grommet kit (including cutter, punch and die) and a couple of other things.  I ordered 36-inch-wide cloth, with plenty of extra for screw-ups.  The supplier sent me 56-inch wide cloth by mistake (I think) so rather than sending it back I used it.  It took fewer seams and I have even more left over, but the wider expanses of cloth were a little harder to handle.  All in all a good outcome.

Sails are actually airfoils, similar to wings.  They work better if their shape is optimized, and that involves curvature in three dimensions and things such as flare and camber.  Last time I made sails I knew nothing about this and I cut and sewed them dead flat.  They work OK (they stretch and bend with the wind) but I wanted to do better this time.

Before I go on let me spell out the terms.  A trapezoidal sail has four sides and four corners.  Not surprisingly, each has a unique name, obscure to all but sailors.  The four sides are foot (bottom), head (top), luff (leading edge, forward), and leech (trailing edge, aft).  The four corners are tack (forward bottom), clew (aft bottom), throat (forward top) and peak (aft top).

To put some 3-D curvature into the sails, I did the following to each:

1.  I put a curve in the foot (about 3 inches maximum).
2.  I put a curve in the head (2 inches max), partly to accommodate the bending of the yard.
3.  I sewed a dart starting at the tack (3/4 inch maximum fold width, or double that in total overlap) and moving up and in diagonally.
3.  I used broadseaming, that is seams of variable width, with maximum at the luff and minimum about 40% aft.  I used a rule of thumb of about 1/2 inch extra seam width per 30 inches on the luff end, less at the leech.

Working with sailcloth is tough.  It's slippery, crinkly and stiff.  Plus I had to remember after several years how to wind bobbins and thread the sewing machine and all that.  Plus one of our cats went nuts with all the thread, tape, scraps and crinkly cloth, so I had to lock her away many times.  But I am happy to say that the basic cutting and sewing of the sail shapes is done. 

The next steps are:
1. Sew on reinforcing patches for the four corners.  Ditto for the extra tack and clew corresponding to each reef.  I intended to have two reefs in each sail but may keep it to one.
2. Finish the foot and leech by sewing the edges under.
3. Finish the luff and head with tape.
4. Put in grommets in the four corners (and reef corners) and along the head (to lash it to the yard).

I will post photos once the sails are nicely finished.  After that there is also sewing the reef points and batten pockets.  I'll explain then.

Until then, keep checking 176 inches.