warning: not an update on the titan build
How I typically class ships from Corvette to Titan:
Corvette = sub 10k mass and around 100m in longest axis, with a preference for speed over firepower and defence. Often a good idea to use them for scouting and defending fighter squadrons. Classification includes Light-Corvette, Medium-Corvette, and Heavy-Corvette.
Frigate = sub 30k mass and around 150m-250m in longest axis, made to fight multiple smaller targets while remaining as fast as possible without hindering offensive or defensive capabilities. Often a good idea to use them as escort ships for larger BattleCruisers. Classification includes Light-Frigate, Medium-Frigate, and Heavy-Frigate.
Destroyer = sub 50k mass and around 170m-300m in longest axis, designed to fight a single larger target, sacrifices on speed to keep good defence and offensive capabilities are ok. Often a good idea to use them as main fleet ships as multiple will be a threat to most larger ships. Classification includes Light-Destroyer, Medium-Destroyer, and Heavy-Destroyer.
Assault variants of Destroyers and Frigates = primary focus on close range weaponry and mobility over defence.
Corvettes, Frigates, and Destroyers are line-ships
Light-Cruiser = sub 100k mass and around 350m-400m in longest axis, designed to fight either a similar sized ship or smaller line-ships. Often a good idea to field them in pairs to flank a larger target or to act as a shield for smaller ships. Classification includes Light-Cruiser.
Medium-Cruiser = sub 150k mass and around 400m-500m in longest axis, designed to fight light cruisers and defend line-ships and Titans. Often a good idea to use these alongside Destroyers to provide more firepower to the frontal attack and allowing it to last a bit longer against an overwhelming foe. Classification includes Medium-Cruiser, and Carrier/Cruiser hybrids.
Battle-Cruiser = sub 500k mass and around 600m in longest axis, designed to fight cruisers and supplement the firepower of battleships and to when used in groups to engage Titans. Often a good idea to use these as the backbone of a fleet and to make a second attack line/defence line. Classification includes Battle-Cruiser, Heavy-Cruiser, and Carrier/Cruiser hybrids.
Battleship = over 500k mass and around 800m in longest axis, designed as a general purpose combat ship to fight both smaller targets and similar sized targets. Often a good idea to keep these at a longer range from an enemy fleet to better use a large cone of fire to damage a lot more enemy ships, or to use them at close range to cripple enemy Battle-Cruisers. Classification includes Battleship, Dreadnought, Battleship/Carrier hybrids, and Sub-Titan-Capital ships.
Titan = over 1million mass and over 1km in longest axis, designed as a general purpose combat ship to fight entire enemy fleets. Often a good idea to: A. not use these. B. keep them a large distance from the enemy fleet and use it as a command centre while providing fire support to your friendly fleet at long range. Classification includes Mobile-Command ships, Capital ships, Titans, Super-Titans, SuperCarriers, and Armed-ColonyShips.
these are just a few of the many classifications, but it is generally what I use most of the time