I managed to put the bottom of my car door though one side of my luff sleeve. It looks like a pretty solid area that might be hard for sail maker to fix. Thinking of just sailing it with tape, unless it's likely to extend the tear.
It depends a little on where it is, I think. If it is just on one side of the wide luff and the main, central part, of luff is undamaged, then I think tape will do fine. The wide luff itself does not have much tension, it is only there to guide the wind, while all the load is taken up by the central luff part.
I've found that the kevlar repair tapes don't seem to have the adhesive qualities of dacron stickyback. Dacron stickyback (not lightweight spinnaker repair tape, but the heavier grades that come in about 1m wide rolls) is amazing stuff even when sticking offshore racing yacht sails back together.
Others may have had different experiences, but the stickyback is certainly my preference.
Gorilla Clear UV stabile tape for X-ply (invisible, and does not change color/fade), and Gorilla Ducktape (various colors) everywhere else. But you could use the Gorilla Ducktape on X-ply, it is the stickiest.
The gaffa and other duct tapes are not suitable for sail repairs, or anything else than something very temporary. They age quickly and leave a residue on the sail, this will in turn cause problems for the needed proper repair...
