Hi Jeff,Hi Frank,
Why do the tri-radial sails last longer? The question is kind of academic, as we ordered a crosscut main and tri-raidal jib. But I'm always interested in learning more.
I'm not a sail expert, but that seems to be a consensus among sail makers. As I understand it, because the tri radial sail is made with many small pieces of sail cloth, and seams and stitching are all in different directions, the stress on the sail cloth in a strong breeze is distributed more evenly and the stress resisted more effectively than in a cross cut sail where one long piece of sail cloth goes from the luff to the leach and has that whole length to stretch.
Others may have additional comments, but I don't think there is any doubt that a tri radial is superior to a cross cut sail. But if one only sails infrequently, or in light air, or is on a limited budget, a cross cut may be a reasonable option.