As you say, for the ships to appear in the Ship Viewer they must be inserted in the DB files.
This is a standard line in the DB:
Code:
Am,N,BB,Iowa,NBBIowa,BB61 Iowa,19430222,19800101,1019,South Dakota
1.- Am: ship's nationality. In the Ship Viewer appear only a handful of nations (Am, Ge, Br, Ne, Ja, It).
2.-N: this fields classifies the unit as Combat ship (N), Merchant (M) or Aircraft (A).
3.- BB: Ship Type. Options are the usual designations: CV, BB, CA, CL, DD etc.
4.- Iowa: class name. Every different class name you add in the country DB will appear as a new entry in the Ship Viewer.
5.- NBBIowa: the Unit Definition File (UDF) which has all the data needed in the game, including the model, speed, weapons, armament, sensors etc. UDF's are located in
../Sim/Units folder.
6.- BB61 Iowa: The name of each unit of the class.
7.- 19430222: Comission date, in format YYYY-MM-DD
8.- 19800101: Decomission date.
9.- 1019: a correlative number. No idea what it is intended for.
10.- South Dakota: No idea of what it means. Seems like it has no use in the game.
DB files are also useful for using in Kriegstanz, a very powerful Scenario Editor which takes unit class availability and names from them.
Finally, the description is a .txt file with the same name as the UDF file, but located in the folder
../Text/English/Units.