Give it too me straight, is it possible to build a small ship in FTD that's actually effective in combat without just being a missle carrier?

I really wish sub 200mm guns were worth building in FTD

Is there any way to make an advanced cannon shell smaller than 60mm in from the depths? Im trying to make a compact multibarrel CIWS system with a high fire rate but so far I can't really make the concept work.

From the depths is pretty fun if you have the levels of autism needed to play it.