Appendices -- Useful Supplemental Information

Virtually all Dabbler sails have three-strand spun Dacron boltrope on the head (four-sided sails), luff, and foot (unless sail is loose footed). Exceptions are sleeved sails and roller furling jibs. To satisfy our aesthetic sense, we always cut the tape from the cloth used for the sail, tanbark tape for a tanbark sail, etc. Hand-sewn bolt rope is rarely specified today (although we usually get a few palm-and-needle roping jobs each year for customers who want the maximum traditional look, and can afford it). Machine-sewn boltrope is not only faster and cheaper, but actually has some advantages over the traditional way. First, after the tape is folded and sewn to the sail, the rope lies exactly on the leading edge, whereas a hand-sewn rope lies on the side of the leading edge. So the rope-on-tape method theoretically results in a sail with slightly better aerodynamics. Second, the rope is uniformly tensioned on the cloth -- nearly impossible to achieve by hand. Third, the rope is automatically shortened vis-a-vis the tape (due to the combined effect of the fabric being advanced by the machine‘s feed dog, while the rope is retarded by the friction of the special roping foot). This shortening protects the cloth from being distorted by the tension of halyards, downhauls, and outhauls. Finally, because the machine needle is smaller than a hand-sewing needle, fewer fibers are damaged. An alternate to roping is to simply sew on folded tape -- without the rope. Most lofts make small-craft sails without roped edges. The drawback is that there is nothing at the exact leading edge to create a rigid entry for the airfoil. The taped edge may even flop back and forth when close hauled, especially on rigs with free standing leading edges -- like lug sails and sprit sails.

Where and how to end a boltrope? Rat-tailing the rope after it turns the last corner was the traditional way until the advent of synthertic sails and cordage. It isn’t easy to rat tail Dacron rope, but it can be done, and we do it on order. The usual way to end a boltrope is to just heat knife it off and seize it to the sail, trusting to the remarkable strength of Dacron and other polyesters to take up the slack. Dabbler Sails were made that way for years, until we developed a cost effective way to mimic the utility of the rat-tailed roping back in the days of cotton sails. The rope goes around the corner for strength, trapping the corner ring, the strands are separated, and each is “tapered” with a diagonal scissors chop – one short, one longer, and one longest. The surgery is covered with a functional patch.

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