The Latest incarnation of Star Fleet ship registry's can be very confusing at first glance, although is very logical.
AA-XYZZ
Above is a sample of a registry. the 'AA' is replaced with 2 numbers depending on the ships class. For example a light cruiser has an alphabetic number of LC so the 'AA' above would be replaced with LC if the ship was a light cruiser. The full set of alphabetic numbers can be found below.
The 'X' is replaced with a number depending on the ships fleet. On the Star ship Specifications pages an * will be shown where the 'X' is above. The * is replaced with a number depending on the ships fleet, should the ship be in the 1st fleet then the 'X' or * would be replaced with 1, should it be second fleet a 2 and so on
Next is the 'Y'. Each class is assigned a number aswell as its alphabetic number.A light cruiser (LC) has a number of 2 so the 'Y' would be replaced with a 2.The full set of numbers can be found below.
Last is the 'ZZ. The 'ZZ' is replaced by a number depending on the ships hull. The first ship in a class, for which the class is named after, has a hull number of 00. The second ship in a class has 01. The full set can be found on the ships specifications pages alongside the ship names.Some classes run over 100 hull numbers, for this the over 100 hull numbers would just be 101,102 etc.
Destroyer. Alphabetic number:DE Class number:1
Light Cruiser. Alphabetic number:LC Class number:2
Marine Assualt ships. Alphabetic number:MA Class number:3
Heavy Cruisers. Alphabetic Number:HC Class Number:4
Battleships. Alphabetic number:BS Class number:5
Carriers. Alphabetic number:CA Class number:6
Science ships. Alphabetic number:SS Class number:7
Medical ships. Alphabetic number:ME Class number8