Understanding JMSDF Hull Numbers
A JMSDF Helicopter Destroyer (140-series hull number) and Missile Boat (800-series hull number) The JMSDF utilizes a hull designation system that is on the surface quite similar to that of the USN. However, a second look will reveal that it does not follow the same rules. Hull designations are not unique (there have been two of DD-101 through DD-119) and numbers are assigned out of order (DD-101 immediately followed DD-158). But on closer examination, one will discover that it actually conveys more information than the USN system. The principle that must be remembered is that, in contrast with the USN, it is the numbers that are the key while the letters are actually somewhat redundant. All JMSDF ships, regardless of letter designations, follow the same set of rules for number designations. The first rule is that the leading digit of a ship’s number (when combined with the total number of digits) reveals her general class - for instance, all destroyers have a number in the 100 r...