Sail repair material and sail repair tape are incredible. We just crossed the Pacific and had to keep repairing our 25 year old sails
to make the trip. (Main issue was with the furled headie, some genus had rolled it on the WRONG way... so for years in the Mexican sun, the UV material was safely rolling inside! This meant we had a foot of very damaged head
sail for the voyage)
Round off corners is a good trick. Also slightly alter the position of repair material on each side of the sail, stagger or off-set it slightly. This trick was from a sail maker, keeps from creating a 'hard' edge with both pieces of repair material cut and fitted at the exact same area. Match the sail tape to your 'white' sail color, but also we have some transparent
repair tape that is perfect for spinnakers, as you don't have to carry every color of your spinnakers that way!
When far from a sail maker, and a rip occurred, this was our course of action:
1.) get to the rip ASAP (the old "a stitch in time, saves 9" stitches! is so true).
2.) Clean the area well - rubbing alcohol will clean and self-dry quickly.
3.) Use a hard surface to flatten the sail and re-align it before applying the repair tape or material - we used one or more cutting boards from the kitchen for this, anything flat and hard will work... even the deck
4.) For load bearing rips, we use sail tape on each side of the rip, then a section of sticky-back material, THEN
5.) Bar-tack it. Hand-stitch a few box reinforcements in the corners of the repair (making a small square of four needle holes and tying off each stitch in the corner, remember on old sails
, each needle hole will also weaken the material, so you are bar-tacking the new sail repair material to itself, with your old sail in the middle).
This would often last until the next port or longer. Once at the next port, we would visit a sail maker, for the bad or heavy load area rips. To save money
often would just have the sail maker add material right over the taped area and stitch over it all with new cloth on both sides.
We have sail tape that still is stuck on after 12,000 miles of sailing! Can highly recommend sail repair tape and sail repair material!