Seal all cut edges with a candle or lighter. This will prevent fraying and also eliminate the need to zigzag seams. Use nylon or polyester thread. Do not use thread with any cotton content--it will rot. Coats & Clark 100% nylon upholstery thread works well. You can also buy 100% poly serger thread in a 1000yd spool.
Cut the tunnel from one end of the fabric. Cut the tunnel 2" wider than your tunnel's intended height. The top 1 1/2" will become the casing for the elastic drawstring, the bottom 1/2" will go into the seam with the skirt itself. Turn the top down 1/2" and iron; fold this down another 1" and iron again. In the center of the tunnel fabric, just below your second crease, sew in two buttonholes or install two grommets for the drawstring bungie to exit. Sew the short sides together (right sides together) and then sew down the top casing. A large safety pin works well for fishing the 3/16" or so bungie through this casing. Install a cordlock and knot the ends together.
Skirt method 1: Set one side of the remaining fabric over your cockpit. If you cut out the sprayskirt on a bias (45*) you'll have more flexibility to fit different-sized cockpits. Trace the outline of the cockpit coaming with a white pencil or crayon (or dark pencil if you'r using light fabric). Cut 3/4" all around this line. Cut strips of fabric 4" wide from your remaining fabric. Sew these together to make one long strip the circumference of your cockpit. Iron down both edges 1/2" to the inside. Iron this strip in half so you have a doubled 1.5" wide strip. Starting at the center back, pin this strip around the edge of the skirt so that the skirt edge is sandwiched between the folded edges of the strip. You'll want to put 1/2" of the skirt edge into the fold, so that 1/4" of the excess you left is left out to help the skirt conform around the coaming. Sew this seam very well. Leave the ends of this tube open at the center back for the big bungie to exit.
Skirt method 2: (The Charlie Walbridge Boatbuilder's Manual Technique) Lay your fabric upside-down over the coaming. Size a knotted piece of bungie to fit around the coaming. Snap the bungie on over the fabric. Cut the fabric 2" around the bungie. Cut a slit in back for the knot to exit and flame-fuse the edges of this cut. Coat the fabric liberally with Aquaseal and fold it over the bungie and over the coaming. Tape it in place to dry. This method also works for Neoprene.
Sketch an oval on your sprayskirt with the same circumference of your tunnel, and cut 1/2" inside the line. Snip from the edge to the line about 2" apart. "Easing" the seam like this will help to pin the straight edge of the tunnel to the curved edge of the hole. Pin the tunnel to the skirt, right sides together. Sew 1/2" from the edge, and seal all seams with Shoe Goo or Aquaseal. (The Aquaseal works slightly better, but Shoe Goo will adequately stick to nylon and is about 1/4 the price. Save your expensive Aquaseal for drysuit and wetsuit repairs.
Sew a 12" piece of tubular webbing to the front of the skirt for a grab loop. Put a half-twist in the loop so that it doesn't lay flat, making it easier to grab. You can sew both ends below the skirt, or one over, one under, with the skirt sandwiched in between. Do not sew both ends above the skirt, as you could rip the grab loop right off the skirt in a panicked wet exit and leave you stuck in the cockpit with the sprayskirt still on.
Pull some 1/4" bungie through the outer tube and adjust for a snug fit on your cockpit.
It is simple to sew on a small casing underneath the skirt deck to slip in a 1/4" x 1/2" piece of aluminum stock for an implosion bar. Okay, maybe a big chunk o' plastic for saltwater paddlers.
Suggested fabrics for sprayskirt: Ambush Cordura, *coated packcloth, *coated oxford nylon, *500-denier nylon, *heavy Ultrex, heavy Goretex. (*delaminates with heavy use over time)
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Copyright © 3/5/2000 Shawn W. Baker