Today, when to find sail numbers we simply use the formula A=10, B=11, C=12....ect. But what about really old Lasers? The early 70's boats have sail numbers litterally of what their hull numbers are....such as 255 who's picture used to be on laser.org. At what point do we switch from going from the hull numbers to the formula? My 1974 Laser's sail number according to the formula is 281305....but that really doesn't make sence because I've never seen a boat with a sail number like that before. Am I mistaken??