You can coat sails yourself with Ultramar Sail & Spinnaker Coating.
- Lay your sail down on a clean surface. For example, a foil from the hardware store.
- Then treat one side with a paint roller or spray and let it dry.
- Then turn the sail over and treat the other side.
Optionally, you can leave the sail on the boat. For example, a mainsail you can hoist, treat, hoist, treat etc. a bit at a time.