Logan,
I just saw your message. I would not sand where you are going to put the letters, no need to. If you are repainting the boat, do it first and get it where you want it but don't wax it yet. Put graphics or letters on and then wax over everything. I would suggest a local vinyl sign shop for your letters as they will have them mounted on some tape that will allow you to place it where you want as a whole and then peel the tape off the outside. Hope this helps.
Matt
I just saw your message. I would not sand where you are going to put the letters, no need to. If you are repainting the boat, do it first and get it where you want it but don't wax it yet. Put graphics or letters on and then wax over everything. I would suggest a local vinyl sign shop for your letters as they will have them mounted on some tape that will allow you to place it where you want as a whole and then peel the tape off the outside. Hope this helps.
Matt