Waterproof? Have you ever tested that?
I'm not so sure, having used them in the office virtually since their inception.
Anyway, when they are mounted on the boat / ship they need sealing in with a coat of clear lacquer
or they may sometime 'float' off again.
Apart from that have not yet seen any transfer paper made for Laser printers. Transfer paper made for ink jet printers may melt 😲 in laser printers in the final transfer / fixing unit.
I can tell you, it makes an 'orrible sticky mess wot ain't easy to get rid of. Doug