Carrier

• Big ship that carries a lot of crew, equipment, and airplanes.
• Typically do not travel alone.

Cruiser

• Originally, a big ship meant to sail around and be seen.
• Nowadays mostly for holding and firing guided missiles.

Destroyers

Created to carry torpedos--a weapon to attack heavily armored that were heavily armored from the surface.

• "Torpedo boat destroyers" were meant to be fast enough to evade a Battleship's massive guns.
• "Protectors of the fleet." Carries anti-submarine equipment or anti-air missiles; whatever counters bullshit that tries to be sneaky on the fleet.

Frigate

• Relatively small weapons. Good sensors, anti-submarine, minor defensive, that's about it.

Corvette

• Small ship. Typically outfit for a single task. Ranges out from shore for smaller missions and not typically out in the deep ocean on their own.

Submarines

• Underwater sneaky breekies.