Deciphering serial numbers

Thanks to the Laser Sailor who helped me with my previous posting.
I now have (I think) all the serial number:

ZFSA4793M82D [either a 'D', or a 0{
Yellow Hull ...
ZFSA a Canadian Builder?
4793 the Hull Number?
M82 - May 1982 build date?
D - no clue
Thanks!