Making a rubbing of the numbers can be helpful .....using a pencil and paper and some masking tape to hold the paper in place over the hull numbers while you rub out the rubbing.
For registering a 30-year old fiberglass sailboat, and providing hull identification at time of registration without having the boat present, the MP suggested I create a rubbing .... just like what's done with an old grave stone...and the MP looked up the 17-digit hull number in their computer info reference data-base to match up the sailboat with the hull number....and it worked out hunky-dory.....because it was a dory!
You just show up at the temporary MP-Hqtrs in Laconia, next to the county jail, and bring along your rubbing etching, pencil drawing paper for positive identification, and they will take it from there!