umm. sticky back?

Packaging tape.. 3m make it in 6 different colours plus the standard brown, and it stays on really well provided you clean the sail before applying it - use some decent window cleaner, or meths on a lint free cloth. For a bubble free application, spray a mist of water onto the sail first, and then you can position your number and squeegee the water out. (like window tint on a car)

Making the numbers is pretty easy - just stick tape to a piece of clean flat glass, and cut them out with a sharp pointed knife. You can peel the tape off the glass easily and transfer it to your sail.

Duct tape works well too, but doesn't come in as many pretty colours. It is solid colour though rather than being slightly translucent like the packaging tape.

Tape has the added bonus that when you poke a hole in your sail, you already have some tape handy that you can re-position!!

Most sailmakers (maybe good marine shops too) stock a self-adhesive sailcloth it's on a 1.5 m wide roll and from memory about $25 / m you can get all different colours. I've also used it to replace entire panels of decaying monofilm.

Just what board crazy above has already said!

Hi

I use book cover contact you get from Woolies or newsagents. It is easy to put on and peels off leaving no residue. I use my PC to print an outline on a sheet of paper of each character and use this as a template to draw the character onto the contact.

You can get colours and use any font you want. Just take your time when you stick it on the sails.

I plot and cut vinyl signs and I have been charging $3 per digit. Looks like I need to put my prices up! way up! and I've been using top of the range avery 900 vinyl

boat rego numbers/letters.200mm , a dollar each. black or white stickers. most chandlerys.