[Soulfisher]

Wanderer's description of warships from 1805 to 1942 is exactly what I've been thinking. As technology advances allow larger hulls, the size of a "battlecruiser" will change over time. But Fyron has a good point when he mentions ship sizes can not be obsoleted. That could get cumbersome.

Maybe, instead of increasing ship sizes, new Ship Construction levels could add new mounts for each size hull. Since mounts can not be obsoleted either, this would generate a huge pile of obsoleted mounts in the late game. Hmmm...

Preferably, whenever a new ship size is introduced, it should have its own identity from the other sizes (which is what un-modded SEIV does, to some extent). I also like SJ's idea of rapidly increasing cost with only a modderate increase in size.

Ed Kolis brings out a good point with his tentative ship size listing: an ability to build "Battleship" type ships on tech level 1. I like this idea; I'll probably introduce a "Battleship" size much earlier in my mod's tech tree than I was originally planning.

Perhaps a combination of both increasing ship sizes and increasing mounts would serve to keep all that obsolete clutter from accumulating too much. Of course, new mounts could be made to apply to only one ship size, then increase ship sizes slowly. Later, new mounts could revitalize older, smaller ships - if made only for them.

As a side note (as it doesn't really fit here), Ed Kolis and Chief Engineer Erax mention that fighters and Carriers are underpowered. I agree! Most "capital ships" (whatever that may be defined as) should have a very hard time dealing with fighters (except for anti-figher ships). Unfortunately, it would be difficult to get the AI to defend itself properly.