Dave, thank you. You've posted several very helpful comments responding to my questions while working my way to a new sail.
This morning I called Aaron Norris, Custom Canvas
in Mystic, CT. He made our mainsail
years ago, and has been our sail repair person for 25 years. I usually listen to his advice and experience. Aaron repaired the UV degraded leach last winter and told me it was delaminating then, he said it would become a "bag of strings". I am usually optimistic about sails and thought that would be a couple of years more.
This morning he advised that he would have to sew the sail at at least 1' intervals and even then the tafetas will not be contributing to the strength of the sail and the new sewing threads are not intended to provide the necessary shear after the adhesive has failed, so he thought the 4-6 hours of work would be a waste of money
, particularly with the mylar being thinner.
Accepting the fact that one of my favorite sails (great shape holding) is now bag material, and that my Marathon 3DL 95% is on the way to the same use. I discussed what the new sail should be. He had originally suggested I look at a Hood
Vektron Sail. After educating myself about all the different sail cloth, cuts etc now available (from expensive load path to radial laminates/dacron to simple dacron, and getting prices from a number of lofts, it have come to the conclusion that I am not going to want to buy another new sail for a very long time and we will only do 1-3 races per year (at most) so the requirements have changed a little. Less shape holding needed, greater longevity, less mildew prone, best dacron cloth available with a miter or crosscut.
I really like and understand the loading concept
of the Mack miter cut jibs which puts the fill threads aligned with the the split load path of the jib
sheet along the foot and the leach. This cut made a lot of sense to me since we tend to have to roll this 140% jib
up a lot when the wind
gets above 12-14 knots. (The jib is the equivalent of 156% on a standard Bristol 32). Their price
was very reasonable and I liked their sails, as seen at the Newport Boat Show
. I agreed with Travis's description about the load path and the fill alignment of a miter cut sail. The Hood
sail is considerably more expensive.
So I asked Aaron if he had worked on Mack Sails and told him that we had settled on Challenge Marblehead Low Aspect 6.77 oz for the quote. Aaron said he had seen Mack sails and they were reasonable but the mitre cut is an older cut and is not necessary. They both work, and can be furled to 25% for shape and beyond to get home. We had some short discussion about Radial Cut because I said furling
them changed the load path from what was designed, more so than miter and cross cut. Aaron said they could be furled to 20% and all cuts get puckered at the corners if furled greater than the designed point, to get home.
I asked Aaron what material he would use. He said Hood Vektran, saying something like it is "bulletproof". This was interesting to me because I had been studying cloth and in particular looked at the Kuraray Vectran engineering specs. Vectran HF degrades to 30% strength with 400 hours of UV. Vectran HF does not shrink as much as Dacron, so they have to preshrink the Dacron in the fill direction which is the direction of the Vectran too. Then the warp threads are fully shrunk with the 104 High Mod fibers. Hood changed to Challenge Looms when the old slow very tightly woven Irish mill went out of business about 2008. I believe the quality is just as good because the 104 fiber has more stretch during the heat treatment which really tightens up the fabric
. What this means is the warp threads shrink more around the fill threads and I believe the thickness of the warp and fill is pretty close. I am told the vectran threads which are about 3/8" apart are protected from UV by clear warp threads. After studying vectran I was not convinced about using it with Dacron and some said it was just a marketing
ploy, but Aaron's enthusiasm for the Hood cloth and the quality of the Hood sail are all very strong factors to consider.
Anyway, during the conversation Aaron said the sails are very well made and he wanted me to come see some very old sails that just came into the loft for end of season check. Which we will do next week.