That's not something we, or any other modders, can really do at the moment
This feature seems to have been planned in the game, but was never finished (as some ship types do have a list of names in their config).
Observer's Ship Name mod, which goes with the Historical Tonnage mod, changes them to more generic "Large Merchant", "Medium Tanker", and so on. It's technically better than the default game, since sinking C2's all the time is far from realistic - only one C2 was sunk during the whole war!