Liquid Electrical Tape
According to Star Brite, liquid electrical tape creates a waterproof seal that is UV, fire and chemical resistant. It is also very flexible which would allow for the coated switches to move easily when the tape is applied. It also takes only 10 minutes to dry and a day to cure AND it comes in a range of various colours for all your boat decorating needs. What more could you ask for?
Possibly here: McMasterCarr.