Re: help with ship clasifications
Terminology changes between ages - 'Frigate' has meant many things - but the Age of the Battleship ended in WWII, so here's the rough guide to names and sizes at that time:
Battleship - 25,000 tons or more, up to ~70,000 tons. Guns in the 14"-18" range (usually 16"). Thick armor - 4-6" deck, 12-16" sides.
Battlecruiser: 20,000 - 40,000 tons, 12"-16" guns. Lighter and faster than battleship with same guns - "Can outrun what they don't outgun." - due to thinner armor (2-4" deck, 8-12" sides). Not known as a successful class.
Cruiser: 8000-10000 tons. Generally carried 8" guns. Long ranged - name derived from role of "cruising" the sea lanes. 2-3" deck, 4-8" side armor.
Light cruiser: 6000-8000 tons. 5-6" guns, some also had bank of torpedoes. 1-2" deck, 3-4" side armor, usually faster than heavy cruiser and shorter ranged.
Destroyer: 1000-2000 tons. 4" guns (some had 5"), 4 to 6 torpodoes, also depth charges. No armor. Name derived from "Torpedo Boat Destroyer" - original role was to screen large ships from craft armed primarily with torpedos, prior to WWI the two types merged (except in German Navy which still operated Torpedo Boats in WWII). Also given role of anti-sub warfare (ASW). Fastest class of ship, 33-38 kts. Not long ranged.
Frigate: Similar size to destroyer but slightly smaller. Carried 4" guns but fewer than destroyer, and no torpedoes. Intended for convoy escort and hence slower (20 kt) but longer ranged. Due to ASW role, primary weapon was depth charge.
Corvette: About 1000 tons, single 4" gun, no torpedoes. Slow (15 kt) but long-ranged, also intended as ASW convoy escort so main weapon was depth charge.