It took me a minute to figure this out..... but then it hit me... if your boat is a 1972 she would not have a 12-digit HIN from O'DAY. The USCG 12-digit HIN requirement did not start until November 1, 1973, or about 3 months into the 1973 model year. When most states adopted Titling laws (most around 1989) they needed to assign HINs to older boats and those that really are "Home Built". So, the USCG created the MIC (Manufacturers I.D. Code) to be used by States for their State-issued HINs, these will consist of the State boat registration abbreviation followed by the letter "Z". For instance, in Massachusetts, we use "MSZ" (our Registrations all start with "MS" then add "Z". Rhode Island is "RIZ", Florida uses "FLZ", you get the picture.
You mention that the "DLZ" HIN is on the previous owner's Delaware Registration, Delaware uses "DL" to start start all Boat Registrations....... the HIN was issued by Delaware, thus the "DLZ". As I say, being built prior to the USCG HIN requirement, your 1972 O'DAY did not have a 12-digit HIN from O'DAY, so Delaware assigned one. That is now the "official" HIN for your boat and it has no connection to O'DAY and the number usually has no connection to any Builder's numbering (some might, but most don't).
Prior to the 12-digit HIN requirement, O'DAY marked every boat with 2 numbers, a "HULL #" anda "CLASS#". The Hull Number refered to total O'DAY production (all models) the Class Number refer to how many of that class had been built (in your case, the 22). To demonstrate this, look at hte numbers from my old Widgeon, Hull: 22698 Class: 1791. That meant she was the 22698th O'DAY built and the 1791st Widgeon. There should be a little metal plate in hte cockpit of your boat with those 2 numbers (Hull# and Class#) on it. It may have fallen off long ago, but it was there originally.
Anyway, have no fear.. that DLZ hull I.D. Number is the correct one to use on all registration and insurance forms.
