Originally Posted by firstname.lastname@example.org
We are about to order new sails for our Oday Javelin. We want to know what the 4 digit number on the sail represents so we can have them match the boat hull information. We want the sails to be just like the originals would have been. I can't remember what year our boat is, but it is early to mid 70's.
Your boat should have the id, or HIN on the stern if it is mid 70's, at least my O'day does.
Generally, you can use the HIN as your numbers, the 4 digits should be sandwiched in the middle of all those numbers. Here is a link
that describes it well.