German tanks were always named after big cats. So I suggest using em as a naming convention for their caps as well.
Naming conventions also include the latin number of a line (I, II, III etc) as well as an A (Ausfuehrung / edition) with the respective number.
Edit: Ship classes on the other hand are named after cities or states these days. Koeln-Klasse, Hamburg-Klasse, Muenchen-Klasse, Sachsen-Klasse, Hessen-Klasse etc.