How do you add a ship

[USS Sea Tiger]

Hi all

In wanting to add a new ship, I have the models completed, How do I add her into SHIII,? Is there a naming convention to the 4 letter designators?

for instance,

Using the barham file, I swapped out parts and made the USS Texas, Now rather than having the texas as barham how/what must I change in the files to make it distinguisable as Texas, a US BB?