US Navy Hull Classification Symbols

The system dates from General Order 541 of 17 July 1920, which gave each type a letter and formed the symbol by doubling it: BB battleship, DD destroyer, SS submarine. The symbols are not acronyms; DD means nothing more than destroyer. Other types combined letters instead: CV was filed under the cruiser letter C with the Navy's V for heavier-than-air aviation, and the origin of that V has never been settled. Added letters refine the type. G is guided missile (DDG, CG, FFG, SSGN), B ballistic missile (SSBN), and N as the last letter is nuclear propulsion (CVN, SSN, CGN). Amphibious ships start with L for landing and spell out the deck arrangement: LHA and LHD are big-deck assault ships, LPD a transport dock, LSD a dock landing ship, LCC a command ship. Auxiliaries start with A: AO oiler, AKE dry cargo and ammunition, AH hospital ship, AS submarine tender. A T- in front of any of these means the ship is assigned to Military Sealift Command, sails with a mainly civilian crew and is a USNS "in service" rather than a commissioned USS. A W in front marks a Coast Guard cutter. The hull number is a serial within the symbol series, so CVN-78 holds number 78 in the carrier sequence that began with CV-1 Langley, and a reclassified ship usually keeps its number (DLG-16 became CG-16). Parentheses mark a design still on paper: SSN(X), DDG(X). The current rules are SECNAVINST 5030.8D of June 2022, and the Naval Vessel Register lists which symbols are in use today.

One lane per symbol family, one dot per class entering service. The 1950s and 1960s fill the combatant lanes at once with the first nuclear hulls and missile ships. The 1975 reclassification then turns the DLG "frigates" into cruisers and the ocean escorts into frigates. The post-Cold War decades thin out to a handful of long-running classes, and the recapitalization since 2008 adds the symbols a reader meets most often today: LCS, ESB, EPF, the new T-AO oilers and the first new CVN class since the Nimitz.

The carrier series has run unbroken since CV-1 Langley in 1922, which is why the Gerald R. Ford is CVN-78 with only eleven carriers in commission. The Forrestal and Kitty Hawk classes were commissioned as CVA attack carriers; the multipurpose CV concept of the early 1970s and the 1975 reclassification folded CVA and the CVS anti-submarine carriers back into plain CV. The Enterprise of 1961 was the first N: CVAN-65, then CVN-65. Every carrier since the Nimitz of 1975 has been nuclear, so CV without the N now only describes retired ships. To hold that number at eleven, the Nimitz, extended to 2027, is due to leave when the second Ford-class hull, John F. Kennedy (CVN-79), delivers.

Before 1975 the Navy had a type of its own: the DLG, a frigate in US usage, a missile escort bigger than a destroyer and smaller than a cruiser. Because the Soviet Union called ships of that size cruisers, comparisons showed a cruiser gap, and on 30 June 1975 the DLGs became CGs, the nuclear DLGNs became CGNs and the smaller Farraguts became DDGs. The Ticonderoga class moved up from the destroyer symbol, ordered as DDG-47 and reclassified CG-47 on 1 January 1980 for its Aegis system. Since then DDG has absorbed the cruiser role: the Arleigh Burke class, still building in its Flight III form, outsizes the Ticonderogas, and the 15,900-ton Zumwalt kept the DDG symbol with the hull number 1000. The last five Ticonderogas leave by 2029, with the DDG(X) not expected before the 2030s.

FF is the youngest of the doubled letters. Until 1975 the convoy escorts were DE, destroyer escort, the World War II symbol kept by the Bronstein, Garcia and Knox classes; the reclassification turned DE into FF and DEG into FFG, and the Oliver Hazard Perry class was the first to enter service as FFG. When the Perrys left in 2015, the small combatants that replaced them were LCS, littoral combat ship, with odd hull numbers for the Freedom monohull and even numbers for the Independence trimaran. A 2015 decision to call the up-gunned LCS a frigate never reached the hull symbols; the FFG series resumed instead with the Constellation class, FFG-62, whose lead ship is now expected in 2029.

Every US combat submarine since the diesel Barbel class of 1959 is nuclear, so the N is constant and the middle letter does the work: nothing for an attack boat (SSN), B for ballistic missiles (SSBN), G for guided missiles (SSGN). The attack line runs from the Skipjack through the Sturgeon and the 62-boat Los Angeles class to the Virginia, still in production, with the three Seawolfs numbered SSN-21 to SSN-23 outside the sequence. The missile line opened with the George Washington, a Skipjack hull cut and lengthened for Polaris, and settled on the Ohio class, whose four oldest boats were converted to SSGN between 2002 and 2008 to carry up to 154 Tomahawks; they retire between 2026 and 2028. The Columbia class takes over the deterrent patrols from the end of the decade, while the SSN(X) that would follow the Virginia has slipped to the 2040s.

The L symbols describe what the ship does with its deck. LHA (general purpose) and LHD (multipurpose) both carry a full-length flight deck for helicopters and jump jets, and the Tarawa and Wasp classes both have a well deck for landing craft. The first two America-class ships (LHA-6 and LHA-7) gave the well deck up for aviation space; the third, Bougainville (LHA-8), brings it back. LPD is an amphibious transport dock, LSD a dock landing ship, LST the tank landing ship built to run onto the beach, and LPH the helicopter carrier of the Iwo Jima class, a symbol no longer in use. LCC is the command ship: the two Blue Ridge hulls of 1970 are the oldest deployed warships in the fleet. The 2015 E series sits beside them: the EPF fast transports and ESD transfer docks are T- hulls under Military Sealift Command, while the ESB sea bases were commissioned as USS, which lets them take part in combat operations a USNS cannot.

Auxiliary symbols start with A and add the cargo: AO carries fuel, AE ammunition, AF stores, and the AKE of the Lewis and Clark class combines dry cargo and ammunition in one hull. AOE is the fast combat support ship built to keep up with a carrier group, AH the hospital ship, AS the submarine tender. Almost all of them now carry the T- prefix: the ship is government owned but assigned to Military Sealift Command, crewed by civilian mariners, and sails as a USNS "in service" rather than a commissioned USS. The Henry J. Kaiser oilers of the 1980s are T-AO-187 to 204; their replacements, the John Lewis class, resume the series at T-AO-205. The Emory S. Land tenders are the exception, still commissioned USS as AS, with mixed Navy and civilian crews.

MCM is the mine countermeasures ship, MHC the coastal minehunter; the Avenger class is the last of the line, down to four hulls in Japan after the Bahrain ships were decommissioned in 2025, with the mine-warfare task passing to LCS mission packages. PC is the patrol coastal of the Cyclone class, retired in 2023. Coast Guard cutters use the same grammar with a W in front: WMSL for the Legend-class maritime security cutters, WPC for the Sentinel-class patrol cutters, WHEC and WMEC for the older high- and medium-endurance cutters.