I have read that there is supposedly two places where
hull numbers are located on vessels, one typically on the transom and the other in a hidden place that only the manufacturer is supposed to know, but often they are carved in place in very visible locations of the inner
hull.
I purchased a brand new Hobie tandem Island Adventurer a few years back and it was not numbered at the factory, so I had to write to Hobie to ask for them to assign one for titling. I was thinking of placing my own hull identification on it, being a Star Wars fan - "Hobie-Wan Kenobi"