Using the A-B-C and on suffixes would be more logical, instead of issuing completely remakes of a type number.
Now, there's another thing however...
B-52: Bomber 52.
F-14: Fighter 14.
C-130: Carrier 130.
And so on.
Thus: CV and CVN are two different designations to a ship's capabilities/function.
Albeit, for ships I do not know their full function's name.