In our ongoing quest to improve and extend the lifetime of sails, we've come across our own method of protecting the sails from sun damage. We repair a lot of sails that come from sailing charter companies; and while they don't see as much abuse from stress and hard sailing, sun damage is the most common killer of their sails because these boats often run 2-3 trips a day. Many times, the sail isn't fully packed away into the bag when they are between trips and they are exposed for a few hours a day. Every hour a sail is left out in direct sunlight is roughly an hour taken away from the life of the sail. We did some internet research and we asked around to some sailcloth manufacturers and we discovered that the white paint they used on UV resistant Dacron contains titanium dioxide. It is the same type of paint used to protect the wings of ultralight aircraft. It's also the same ingredient in white UV resistant latex house paint. (who would have thought?) We decided to test it out for ourselves by painting the leeches on a couple head sails as a cheaper alternative for making an entirely brand new Sunbrella cover. A can of high quality UV paint is about $40 opposed to $400 worth of Sunbrella (not including the labor cost to sew it on). It's been over two years on our first sail and its still in good condition.
This week we got a brand new main sail in the loft, so we took preemptive measures and painted the head of the sail which is the part that is most exposed to sunlight. It will likely extend the overall lifetime of the sail and hopefully it will be a while before we have to see it again for repairs.