HIN Number?
Just curious, why is not having the number so important in this case? At one time, no boats had the HIN number. (It's a good idea that they do now, however). If you have a notarized bill of sale, you should be ok. If you want an identifying number, you can select a number, glass it in somewhere visible, like in a locker, if you want an identifier for the future (could also put in duplicate in some hidden spot, if you are worried that the number might be removed if the boat was stolen from you). If you then sell the boat later, you could put this number on the new bill of sale. (In high school, many, many years ago, I worked for a company that was a state license agency. People would come in with home built trailers that had no identificating number. We would take a set of dies and stamp a number on the trailer, which along with other required originating documents, became the official number for that trailer....same idea here.)