a. AD - Destroyer Tender

Despite their title, destroyer tenders service a variety of ships besides destroyers. Destroyer tenders provide a mobile base and intermediate level maintenance support facilities for destroyers, cruisers and frigates.
Ship used to provide base facilities for destroyer type combat vessels. Provides, accommodation for flag staff, ships crews, light repair, training and resupply facilities.

b. AFS - Combat Stores Ship

Provides a mixture of combat stores (ammunition and the like) and general stores such as food.

c. ATF - Fleet Ocean Tugs

Provide the U.S. Navy with towing service, and when augmented by Navy divers, assist in the recovery of downed aircraft and ships.

d. ARS - Rescue and Salvage Ship

Render assistance to disabled ships, provide towing, salvage, diving, firefighting and heavy lift capabilities.

e. ASR - Submarine Rescue Ship

Serve as surface support ships for deep submergence rescue vehicles (DSRV's) during submarine rescue operations.

f. AR - Repair Ship

A conversion of a ship that has been modified to provide structural repairs to a damaged vessel.

g. AS - Submarine Tender

Ship used to provide base facilities for submarines. Provides, accommodation for flag staff, ships crews, light repair, training and resupply facilities.

h. MCM - Mine Countermeasures Ship

Avenger class MCM ships are designed as mine hunter-killers capable of finding, classifying and destroying moored and bottom mines. The last three MCM ships were purchased in 1990, bringing the total to 14 fully deployable, oceangoing Avenger class ships

i. MHC - Coastal Mine Hunters

These ships use sonar and video systems, cable cutters and a mine detonating device that can be released and detonated by remote control. They are also capable of conventional sweeping measures.

j. PC - Patrol Craft

These ships provide coastal patrol and interdiction surveillance. These ships also provide full mission support for Navy SEALs and other special operations forces.

k. SSBN - Ballistic Missile Submarine (Nuclear propulsion)

Strategic deterrence has been the sole mission of the fleet ballistic missile submarine (SSBN) since its inception in 1960. The SSBN provides the nation's most survivable and enduring nuclear strike capability.

l. SSN - Submarine (Nuclear propulsion)

Attack submarines are smaller than ballistic missile submarines and do not, as a rule, stay at sea as long. The mission of these fast and silent SSNs include attacking enemy ships-- both surface and submarine and in supporting land-based campaigns.