I've been doing quite a bit of preliminary sketching. It's nothing too good yet (nothing I'd post on the HLP), but it's just to get things rolling. While doing that, I've come up with some vessel conventions. Whether or not they're used doesn't matter.
General Warship Conventions (Excludes Carriers) by Size:
"-Boats": < 250m. "Boat" is a suffix applied to a small craft designed to provide high-speed/mobility combat capabilities against larger vessels. Typically lightly armored but utilizing a highly specialized loadout in relation to their high speed makes these smaller vessels a credible threat. Gunboats, missile boats, and torpedo boats are the most common.
Frigates: 250 < x < 450m. A light combat and patrol vessel. The primary role of the frigate is to provide AA coverage to a convoy or battlegroup. The vessels also will tend to have light anti-vessel capabilities as well.
Destroyers: 450 < x < 750m. A larger combat vessel than a frigate, the destroyer is a potent mix between an AA vessel and an anti-vessel platform.
Corvettes: 250 < x <800m. A varied class of warship which often fills a niche between that of a frigate or destroyer. Corvettes however are biased towards speed, often sacrificing armament and armor. This makes them a typical offensive weapon.
Cruisers: 750 < x < 1100m. The typical fleet anti-vessel platform. Possessing powerful artillery and missile systems, the cruiser makes for a formidable foe.
Battlecruisers/Pocket Battleships: 900 < x < 1750m. HEAVILY armed and armored, both classes of vessel are a significantly more serious threat than a criuser. The difference is here: the battlecruiser is biased towards speed while the "pocket battleship," like its name implies, is a slower, more heavily armed and armored vessel than a cruiser.
Battleships: 1500 < x < 2100m. Ususally the top of the cap-ship foodchain, the battleship brings down massive amounts of firefower upon any foe in its vicinity.
Monitors: 2000 < x < 3500m. "Hell on... wheels" would not be applicable, as this is space. Battleships are mighty, but also generally regarded as practical. A monitor possesses such armor and armament that its mass gives it so little forward acceleration in comparison to other warships that, were it not for the weapons and armor that made it that way, would be little more than a massive target in space. As such, they are limited in where they travel. A gravity well which may give a smaller vessel only little difficulty could spell the end of a poorly handled monitor.
Dreadnoughts: 3500 < x < 4500+m. Terror has never been so magnificently embodied by one of these ships. Much more impressive than the already devastating monitor-type vessels, the dreadnought is in many ways more viable. Though more heavily armed and armored than a monitor, the dreadnought also employs much more volume for engines and reactors, giving an edge in the power-to-weight ratio when compared to a monitor. Only one class of this vessel type has EVER been employed by the Terran Navy.
Juggernoughts: 4500 < x < [beyond]m. This is a designation reserved for the most unfathomable of space warships. This is a vessel which can enter a system with no fears of being stopped. It travels to its target and arrives. Destruction will ensue upon arrival.
Note: These figures are based around size only.
Well, how did I do? Missing a class of vessel you'd like to see? If so, post!