source: https://www.facebook.com/groups/491974904304507/posts/2681605892008053/

Quote:

There was a recent post asking about removing wrinkles in a rigged sail. The usual responses ensued: correct mast stiffness and bend curve, more or less downhaul, more or less outhaul, more or less batten tension, and faulty sail construction. One post hinted that the 100% carbon mast was too stiff, and a lower carbon content would be softer. Several folks stated that the stiffness and bend curve are independent of the carbon content. After more discussion, I decided to seek the opinion of someone I trust, someone that makes/sells both masts and sails. I wrote to Dave Ezzy for his advice. I am paraphrasing his response to my questions. If the stiffness and bend curve are the same, the sail would be rigged the same. It would not look any different. Weight, durability and dynamic response (return to “normal” after deflecting) would be different, but the sail should rig the same. One caveat, he prefers lower carbon content for “small” sails, 4.2 and smaller, as the high content mast feels more “twitchy.” Nothing less than 60% for him. He added that SDMs perform better than RDMs above 460 length, but would be more fragile due to the thinner wall thickness. Given this, I tweaked a little file I give to folks I’ve taught who ask what to buy. Here is the mast suggestion section. I think it adjusts for performance notes above and makes some allowance for cost: · 490cm and up – 80% or higher – 100 % SDM preferred for weight · 460cm – 75% some preference for RDM for durability · 430cm and smaller – 50-60% is fine RDM for durability