USS Port Royal (CG-73), a Ticonderoga class cruiser.

A naval ship is a ship (or sometimes boat, depending on classification) used for military purposes, commonly by a navy. Naval ships are differentiated from civilian ships by construction and purpose. Generally naval ships are damage resilient and armed with various weapon systems, though armament on troop transports is light or non-existent.

The term "warship" is often used to identify the subclass of naval ships designed primarily as combatants, as opposed to support or yard operations.

Naval ship classification

Naval ship classification is a field that has changed over time, and is not an area of wide international agreement, so this article currently uses the system as currently used by the United States Navy.

Aircraft carrier - ships that serve as mobile seaborne airfield, designed primarily for the purpose of conducting combat operations by aircraft which engage in attacks against airborne, surface, sub-surface and shore targets.

Surface Combatant - large, heavily armed, surface ships which are designed primarily to engage enemy forces on the high seas, including various types of battleship, battlecruiser, cruiser, destroyer, and frigate.

Submarine - self-propelled submersible types regardless of whether employed as combatant, auxiliary, or research and development vehicles which have at least a residual combat capability.

Patrol Combatant - combatants whose mission may extend beyond coastal duties and whose characteristics include adequate endurance and sea keeping providing a capability for operations exceeding 48 hours on the high seas without support.

Amphibious Warfare - ships having organic capability for amphibious assault and which have characteristics enabling long duration operations on the high seas.

Combat Logistics - ships that have the capability to provide underway replenishment to fleet units.

Mine Warfare - ships whose primary function is mine warfare on the high seas.

Coastal Defense - ships whose primary function is coastal patrol and interdiction.

Mobile Logistics - ships that have the capability to provide direct material support to other deployed units operating far from home base.

Support - ships designed to operate in the open ocean in a variety of sea states to provide general support to either combatant forces or shore based establishments. (Includes smaller auxiliaries which by the nature of their duties, leave inshore waters).

Service Type Craft - navy-subordinated craft (including non-self-propelled) designed to provide general support to either combatant forces or shore-based establishments.