3 ship types - but with the same hull and machinery
hmm, how about (for the RN)
use the County Class as the base (i know, it had loads of sub-classes) - but roughly 600ft long, 68ft beam, 80000shp for 31-32knots
CA - 4*2 8inch - armour as per standard County Class, ~10k tons
CL - 4*2 6inch -...