Dibs
The Second Tau Empire ship classification guide: (probably wrong, not on pc at the moment)
Rather than go off cost:
Fighters/Bombers: very small, maximum 8x8 ships.
Patrol boats: small, maximum 14 length ships, made to patrol sectors.
Corvettes: Small, anti fighter escorts, maximum size: 20 length, usually less
Destroyer: Small, anti capital ship, maximum size: 20 length, usually less
Frigates: Small, anti ship escorts, maximum size: 60 length
Light Cruiser: Small, independent ships, maximum size: 80 length
Medium Cruiser: small to medium, maximum size: 150 length
Heavy/Battle Cruiser: medium to large ships, maximum size: 200-250 in length
Carriers: all sizes, maximum size anything in length, must carry fighters/bombers
Battleship: large, minimum size: 200 in length, must have "sufficient" firepower
Sub roles:
ECMS: electronic warfare ship
FAV: fast attack vessel
Escort: Escort designated ships
LRSS: Long range support ship
FSV: Fleet supply vessel (ftl fuel, repairs, ect)