Bullet Proof Sails
The sails on the Nirvana are some of the most unusual in the world- unusual in material and construction. They are virtually indestructible.
These sails are made of a polyester film (one brand name for polyester film is Mylar®) bonded with a polyester random fiber. Even though they look like "rice paper", they are actually very advanced.
Characteristics - These sails are really tough. This material will not absorb water (thus it will not mildew), it will not stretch (like woven sails), and it has very high tear strength. They also have a very good resistance to sun damage. Eventually, in 5-6 years if you do a reasonable amount of sailing, the glue seams may break down from sun damage.
Maintenance - Maintenance is a snap. You should always rinse salt water off the sails, and the rest of your boat. Slack all tensioning devices (outhauls, etc) when the boat will be stored for more than a day. If you ever take the sails off the spars, make sure to store flat. If you crease these sails, they are pretty well creased for life. The good news is that creases have little to do with performance and do not weaken the sails in any way. Rolling these sails is also not recommended because they memorize a curve (which will eventually work out).
Cut Repair - As mentioned, damage to these sails during normal use is really not an issue, even under the worst sailing conditions. However, if you catch the sail on a sharp object or your dog finds them fun to munch on, then you may be looking for a repair kit. It is as close as a roll of clear packing tape. Installed on the shiny side of the sail, it disappears and cures almost any cut.