Hello guys, I've registered a vintage boat under the Polish flag and the Polish certification card has no model , HIN or engine number written on it, how would authorities know this boat is mine?
No idea, but there are plenty of old boats that have no form of identification. HINs did not come in formally in Europe until 1997 and before that builders used many different ways of identifying boats, or not even bothering at all. Proper registration as in the UK Part 1 overcomes this by assigning a number that has to be attached permanently - in proper boats like mine by carving into a fixed part of the boat. In the first photo you can see it on the main deck beam in the forecabin and in the second is the builders brass plate showing it was number 208 built to the design