Hull Classification Symbols, United States


US Navy (1895)

A numbering system for US Navy ships was initially set up in 1895 which was fairly simple, with ships being designated with their full, unabbreviated ship type followed by a number which was assigned in ascending order, unlike the random pennant numbers that the Royal Navy began adopting around this time. As such, the first modern battleship, the USS Indiana was known as Battleship No. 1 and the first destroyer USS Bainbridge was Destroyer No. 1. From 1907 ward, the ship types began to be abbrivated into single-letter symbols such as B-1 and D-1. For some ship types, a multi-letter symbol was used such as for Torpedo Boats (TB) and Armored Cruiser (ACR). Note that it is US practice to assign hull numbers in the order that the ships were authorized by Congress, rather than when they have been laid down or commissioned. It is also customary to name the ship's class on the first authorized ship (ex: the Colorado-class battleships were named as such, even though the USS Colorado was laid down in 1919 and commissioned in 1923, two years after its sister ship, the USS Maryland). This practice has persisted to this day.

Hull classifications
ACR Armored Cruisers
B Battleships
C Cruisers (all other)
CS Scout Cruisers
D Destroyers
M Monitor
S Submarines
TB Torpedo Boat


US Navy (1920-75)

The massive expansion of the US Navy during World War I resulted in a huge number of new ship types entering service which rendered the old classification system obsolete. On July 17th 1920, a new hull classification system was approved which has formed the basis of all hull symbols since. The new system used a two-letter hull symbol which had a base designation for the ship type (first letter) and a suffix for the sub-type (second-letter), followed by a hull number. The new system largely borrowed the designations used under the old system, but given that single-letter hull symbols were no longer allowed, meant that main ship types like battleships and destroyers used the base designation letter twice; this became the origin of the now-famous designations of BB (battleship), DD (destroyer), and SS (submarine). As for numbering sequence, most major combat ship types of the same base designation remained within their number sequence; for example, heavy (CA) and light cruisers (CL) all followed the same cruiser sequence. In contrast, amphibious, patrol, auxiliary, mine craft, and yard craft typically had numbering sequences for each sub-type given that hundreds of these smaller ships are frequently built. Except for certain exceptions described in the next section, the numbering sequence remains uninterrupted to this day. And unlike Royal Navy/NATO practice, no hull number is ever recycled.

Cruisers, which by then already came in various sub-types, were representative of this new system, with former armored cruisers being designated CA and scout cruisers CS. Notably, a new type of ship that became prominent in the 1920s, the aircraft carrier, was given the CV designation as they were orginally considered aircraft-carrying cruisers; the V being standard US Navy designation for "heavier-than-air" craft. As an even wider variety of ships came into service, three-letter and even four-letter hull symbols also came into use soon thereafter, particularly when certain sub-types (like CVs) became main ship types in their own right. Confusingly, the USN also frequently changed prefixes even in short spaces of time, paricularly in the case of new ship types whose role was not firmly established when they were first conceived during wartime. A fine example of this were escort carriers, the first of which were given the designation AVG (Auxiliary Aircraft Ferry) in 1941, then switched to ACV (Auxiliary Aircraft Carrier) in 1942, and finally the definitive CVE (Aircraft Carrier, Escort) in 1943. An illustrative ship during this whole process was USS Card which went through the following designations throughout its nearly 30-year US Navy and Military Sea Transportation Service history: AVG-11 (when ordered), ACV-11 (when built), CVE-11 (1943), CVHE-11 (reclassified as helicopter escort carrier in 1955), T-CVU-11 (utility aircraft carrier in MSTS service from 1958), and T-AKV-40 (cargo ship and aircraft ferry from 1959).

Although hull symbols have changed since (particularly after the 1975 reclassificaton explained below), the base designation prefixes have remained the same since 1920, and in most cases the sub-type prefixes as well. Note that sub-type suffixes generally referred to more than one type of ship, which means that it is not always possible to determine a ship type on the basis of the hull symbol unless one knows the meaning of the hull symbol beforehand. Indeed there are so many exceptions and oddities in the system that it is impossible to list them all. It was also the case that base designations and suffixes were used interchangeably, such as with submarine oilers that were given AOSS and SSO designations at different times. In some cases the same ship type used two differnet hull symbols, such as World War II-era submarine chasers which were assigned PC or SC depending on size; the latter symbol being particularly odd since S is the submarine base designation and SC was also used for cruiser submarines during the pre-war period.

It was common for hull symbols to include more than one sub-type suffix though there has never been a hull symbol with more than four letters. A small number of suffixes are two-letter, such as AC (air cushion), and CM (countermeasures). In some cases, more specific roles for a particular ship type were specified through the use of parenthesis. This was very common with amphibious vessels which were often converted to other uses such as the LST(H) tank landing ship, evacuation (hospital) or the LSM(R) medium landing ship, rocket. Another oddity was the use of an undercase c for certain costal ships such as the AMb harbor and AMc coastal minesweeper. And in the sole case of a hull symbol named for a particular class of ships, the World War I-era Eagle Boats were designated PE.

The following tables list all base designations and the most common sub-type suffixes since 1920 for major combat ship types. Note that there are also two special prefixes in use: US Coast Guard ships before 1965 used US Navy hull symbols with a W prefix, thus a USCG cutter (patrol gunboat) would have a WPG hull symbol. Ships in service with the Military Sea Transportation Service (later Military Sealift Command) would have a T- prefix to their standard US Navy hull symbol (see case of the USS Card above).

Base Designations
A Auxliaries
B Battleships
C Cruisers
CV Aircraft Carriers
D Destroyers
F Frigate
L Amphibious Ships
M Mine Craft
P Patrol Craft
S Submarine
Y Yard craft
Sub-Type Suffix
A Attack / Heavy / Assault / Auxiliary
AA Anti-Aircraft
AC Air Cushion
B Large / Ballistic Missile / Harbor
C Command / Coastal
D Dock / Fast
E Escort
F Flying Deck / Fleet
G Guided Missile / Gunboat
H Helicopter / Hydrofoil / Hospital
I Infantry / Inshore
K Hunter-Killer (ASW) / Cargo
L Small / Light / Large
M Minelayer / Missile / Mechanized / Medium
MS Minesweeper
N Nuclear Propulsion
P Transport
R Radar Picket / Rescue / River / Rocket
S ASW Support / Small / Special / Submarine
T Training / Tank
U Utility
V Vehicle


US Navy (1975-)

The US Navy's hull classification system has been flexible enough to allow the introduction of new hull symbols and the disuse or retirement of others over time. However, a major reclassification took place on June 30th 1975 in response to the controversy over the US's perceived "cruiser gap" with the rapidly expanding Soviet Navy. After World War II, the US Navy reintroduced the pre-war concept of the destroyer leader (DL) and applied this term to large task force escorts that were of intermediate size between existing gun/missile cruisers and destroyers. After 1955 these ships were reclassifed as frigates, which went against the standard use of the term as an anti-submarine escort that was smaller than a destroyer; at the time the US Navy continued the World War II tradition of referring to these ships as destroyer escorts (DE). The result was that by 1975 (when most of the old gun cruisers had been decommissioned) the US Navy only had a handful of ships that were officially classified as "cruisers". In contrast, the Soviet Navy, which tended to build smaller ships of the same type as their US counterparts, had over three times the number.

Naval authorities responded to the political and media "cruiser gap" panic by implementing a major reclassification of the Navy's surface ships. Most of the the former destroyer leaders/frigates (Leahy-, Belknap-, and California-classes) were reclassified as cruisers bringing the total number of such ships to 27 (from just 6) in an instant. This revealed a clear advantage over the Soviet Navy's 19. The only exception was the smaller Farragut-class which were reclassified as guided missile destroyers. At the same time, the destroyer escorts were finally reclassifed as frigates, bringing this in line with practice among other NATO navies. There were an number of other changes such as the removal of the A (attack) suffix for carriers leaving them at CV (conventional) or CVN (nuclear powered). Since 1975 the cruiser definition has been used entirely as a function of capability rather than hull size. This is evidenced by the fact that the Ticonderoga-class is designated as such despite using the same hull as the Spruance-class destroyers and having been originally been designated guided missile destroyers when first ordered.

Although there has not been another reclassification on the scale of 1975, the hull classification system continues bringing up new oddities. For starters, the 1975 changes interrupted the new numbering sequences that had been established in the post-war period where guided missile cruiser, destroyers, and destroyer leaders had reverted to 1 in order to differentiate them from the gun platforms (which continued using the 1920 sequence). The DLG/DLGNs that converted to CG/CGNs required only a change in hull symbol but retained their numbers given that the last assigned cruiser number was CG-14 and the lowest destroyer leader number was DLG-16 (thus, CG-15 was skipped). This was not possible with the Farragut-class ships which were asigned DLG-6 to DLG-15, numbers that had already been taken by existing DDGs. Upon reclassification, their numbers changed to DDG-37 to DDG-46. The Ticonderoga-class was meant to continue the sequence at DDG-47 but upon reclassification as cruisers in 1980 these became CG-47 ownard, resulting in the skipping of numbers 44-46 since the previous Virginia-class cruisers ended in the (unbuilt) CGN-43.

Even more arbitrary numbering followed. The Zumwalt-class began with DDG-1000, which would appear to revert to the 1920 destroyer sequence which ended at DD-997 (the last Spruance-class ship), thus skipping two numbers. Another arbitrary sequence change was the Seawolf-class submarines which began with SSN-21 ("21st century"), the first submarine to break the 1920 sequence. It also arguably violates the no recycling rule since an SS-21 already existed. The subsequent Virginia-class boats, however, reverted to the 1920 sequence beginnig with SSN-774. Earlier, the first hunter-killer submarines were briefly designated SSK-1 to SSK-3 but later switched to the 1920 sequence.

A further post-1975 quirk is the introduction of hull symbols that do not follow any base designation/ship-type suffix and instead are acronyms of their ship type. The most obvious example of this practice are the littoral combat ships of the Freedom- and Independence-classes which are designtaed LCS. Their numbering sequence is also unique, with each class getting only odd and even numbers respectively. This could create gaps in the event that more ships of one class are built (construction of both is ongoing). Acronym hull symbols are more common among support craft such as the Advance Base Section Dock (ABSD) or Maritime Prepositioning Force Utility Boat (MPFUB).

The following is a comprehensive list of all hull symbols used since 1920. Ship types in bold are those currently in use as of 2016 (SECNAV Instruction 5030.8C).

Aircraft Carriers
ACV Auxiliary Aircraft Carrier reclassified CVE (15/7/1943)
AV Seaplane Tender  
AVD Seaplane Tender Destroyer Destroyer conversions (WW2)
AVG Aircraft Escort Vessel reclassified ACV (20/8/1942)
AVP Small Seaplane Tender  
BACV Auxiliary Aircraft Carrier (Lend-Lease)  
BAVG Aircraft Escort Vessel (Lend-Lease)  
CV Aircraft Carrier  
CVA Attack Aircraft Carrier reclassified CV (30/6/1975)
CVAN Attack Aircraft Carrier, Nuclear Propulsion reclassified CVN (30/6/1975)
CVB Aircraft Carrier, Large Midway-class only; reclassified CVA (1/10/1952)
CVE Escort Aircraft Carrier reclassified AVK (7/5/1959)
CVHA Assault Helicopter Aircraft Carrier  
CVHE Escort Helicopter Aircraft Carrier  
CVL Small Aircraft Carrier  
CVN Aircraft Carrier, Nuclear Propulsion  
CVS ASW Support Aircraft Carrier  
CVT Training Aircraft Carrier  
CVU Utility Aircraft Carrier  
BB Battleship  
BBG Guided Missile Capital Ship unused
BM Monitor  
CA Armored Cruiser until 1/7/1931
CA Heavy Cruiser from 1/7/1931
CAG Guided Missile Heavy Cruiser  
CB Large Cruiser Alaska-class only
CBC Large Tactical Command Ship retired (unused) 9/10/1954
CC Battlecruiser until 1922
CC Command Ship from 15/4/1961
CF Flying Deck Cruiser  
CG Guided Missile Cruiser  
CGN Guided Missile Cruiser, Nuclear Propulsion  
CL Light Cruiser includes former Protected and Scout Cruisers (pre-1920)
CLAA Anti-Aircraft Light Cruiser  
CLC Tactical Command Ship reclassified CC (15/4/1961)
CLG Guided Missile Light Cruiser  
CLK Cruiser, Hunter-Killer reclassified (unused) DL (2/2/1951)
Destroyers and Frigates
DD Destroyer  
DDC Corvette unused
DDE Anti-Submarine Destroyer  
DDG Guided Missile Destroyer  
DDK Hunter Killer Destroyer  
DDR Radar Picket Destroyer  
DE Destroyer Escort / Escort Ship Destroyer Escort (WW2); reclassified FF (30/7/1975)
DEC Control Escort Ship  
DEG Guided Missile Destroyer Escort reclassified FFG (30/7/1975)
DER Radar Picket Escort Ship  
DG AEGIS Missile Destroyer unused
DL Frigate Destroyer Leader until 1/1/1955; reclassified CG / DDG (30/7/1975)
DLG Guided Missile Frigate reclassified CG / DDG (30/7/1975)
DLGN Guided Missile Frigate, Nuclear Propulsion reclassified CGN (30/7/1975)
DM Destroyer Minelayer Destroyer conversions (WW2); reclassified MMD (1/1/1969)
DMS Destroyer Minesweeper Destroyer conversions (WW2)
DS Surface Effect Destroyer  
FF Frigate from 30/7/1975
FFG Guided Missile Frigate from 30/7/1975
LCS Littoral Combat Ship  
Patrol Craft
PB Patrol Boat  
PC Patrol Craft Coastal  
PC Submarine Chaser (173 ft)  
PCC Control Submarine Chaser (173 ft)  
PCE Patrol Craft Escort  
PCEC Control Escort (180 ft)  
PCER Patrol Craft Rescue Escort  
PCH Submarine Chaser, Hydrofoil  
PCS Patrol Craft Sweeper (? Patrol Craft, Submarine)
PCSC Control Submarine Chaser (136 ft)  
PE Eagle-class Patrol Vessel  
PF Patrol Frigate Tacoma-class only
PG Gunboat includes former Peace Cruisers (pre-1920)
PG Corvette (Reverse Lend-Lease) Flower-class (UK) only
PGH Gunboat, Hydrofoil  
PGM Motor Gunboat  
PHM Patrol Combatant Missile, Hydrofoil  
PR River Gunboat  
PT Motor Torpedo Boat  
PTC Motor Boat Submarine Chaser  
PY Patrol Yatch  
PYc Coastal Patrol Yatch  
RAB Riverine Assault Boat  
RCB Riverine Command Boat  
RPB Riverine Patrol Boat  
SC Submarine Chaser (110 ft)  
SCC Control Submarine Chaser (110 ft)  
AKSS Cargo Submarine  
AOSS Submarine Oiler  
APS Transport Submarine  
APSS Transport Submarine  
ASSA Cargo Submarine  
ASSP Transport Submarine  
ATSS Auxiliary Training Submarine  
IXSS Unclassified Miscellaneous Submarine  
LPSS Amphibious Transport Submarine  
SF Fleet Submarine  
SM Minelaying Submarine  
SS Submarine  
SSA Cargo Submarine  
SSAG Auxiliary Submarine  
SSB Ballistic Missile Submarine  
SSBN Ballistic Missile Submarine, Nuclear Propulsion  
SSG Guided Missile Submarine  
SSGN Guided Missile Submarine, Nuclear Propulsion  
SSK Hunter-Killer Submarine  
SSN Attack Submarine, Nuclear Propulsion  
SSO Submarine Oiler  
SSP Submarine Transport  
SSR Radar Picket Submarine  
SSRN Radar Picket Submarine, Nuclear Propulsion  
SST Target and Training Submarine  
Amphibious Ships
AGC Amphibious Force Flagship  
AKA Attack Cargo Ship reclassified LKA (1/1/1969)
APA Attack Transport reclassified LPA (1/1/1969)
APD High Speed Transport Destroyer conversions (WW2)
LCAC Landing Craft, Air Cushion  
LCFF Landing Craft Infantry, Flotilla Flagship  
LCI(G) Landing Craft Infantry, Gunboat  
LCI(L) Landing Craft Infantry, Large  
LCI(M) Landing Craft Infantry, Medium  
LCI(R) Landing Craft Infantry, Rocket  
LCI(S) Landing Craft Infantry, Small  
LCM Landing Craft, Mechanized  
LCPL Landing Craft, Personnel, Large  
LCS(L) Support Landing Craft, Large  
LCT Landing Craft, Tank  
LCU Landing Craft, Utility  
LCV Landing Craft, Vehicle  
LCVP Landing Craft, Vehicle, Personnel Higgins Boat (Unofficial)
LFR Inshore Fire Support Ship  
LFS Amphibious Fire Support Ship  
LHA Amphibious Assault Ship, General Purpose Tarawa-, America-class
LHD Amphibious Assault Ship, Multi-Purpose Wasp-class
LPA Amphibious Transport  
LPD Amphibious Transport Dock  
LPH Amphibious Assault Ship, Helicopter  
LPR Amphibious Transport, Small  
LSD Dock Landing Ship  
LSFF Flotilla Flagship Landing Ship  
LSI(G) Landing Ship Infantry, Gunboat  
LSI(L) Landing Ship Infantry, Large  
LSI(M) Landing Ship Infantry, Mortar  
LSI(R) Landing Ship Infantry, Rocket  
LSM Medium Landing Ship  
LSM(R) Medium Landing Ship, Rocket  
LSS(L) Support Landing Ship, Large  
LST Landing Ship, Tank  
LST(H) Landing Ship, Tank (Casualty Evacuation)  
LSU Landing Ship, Utility  
LSV Vehicle Landing Ship  
Mine Craft
ACM Auxiliary Minelayer reclassified MMA (7/2/1955)
AM Minesweeper reclassified MMF / MSF / MSO (7/2/1955)
AMb Harbor Minesweeper  
AMc Coastal Minesweeper  
AMCU Coastal Minesweeper, Underwater Locator  
AMS Motor Minesweeper reclassified MSCO (7/2/1955)
BAM Minesweeper (Lend-Lease)  
BYMS Motor Minesweeper (Lend-Lease)  
CM Minelayer  
CMC Coastal Minelayer  
MCM Mine Countermeasures Ship  
MCSL Small Mine Countermeasures Ship  
MHC Coastal Minehunter  
MM Minelayer  
MMA Auxiliary Minelayer  
MMC Coastal Minelayer  
MMD Fast Minelayer  
MMF Fleet Minelayer  
MSC Coastal Minesweeper, Non-Magnetic  
MSCO Coastal Minesweeper, Old  
MSF Fleet Minesweeper, Steel Hull  
MSH Minehunter  
MSI Inshore Minesweeper  
MSO Minesweeper, Ocean  
MSS Minesweeping, Special Device  
YMP Motor Mine Planter  
YMS Auxiliary Motor Minesweeper  
AB Crane Ship  
ABD Advanced Base Dock  
ABSD Advanced Base Section Dock  
AC Collier  
ACS Crane Ship  
ADG Degaussing Ship  
AE Ammunition Ship  
AF Store Ship  
AFD Auxiliary Floating Dock  
AFDB Large Auxiliary Floating Dry Dock  
AFDL Small Auxiliary Floating Dry Dock  
AFDLC Small Auxiliary Floating Dry Dock, Concrete (?)
AFDM Medium Auxiliary Floating Dry Dock  
AFS Combat Stores Ship  
AFSB Afloat Forward Staging Base  
AG Offshore Petroleum Distribution Ship  
AG Miscellaneous Auxiliary  
AGB Icebreaker  
AGD Seagoing Dredge  
AGDE Escort Research Ship  
AGDS Deep Submergence Support Ship  
AGEH Hydrofoil Research Ship  
AGER Environmental Research Ship  
AGFF Auxiliary General Frigate  
AGHS Patrol Combatant Support Ship  
AGF Command Ship  
AGL Lighthouse Tender  
AGM Missile Range Instrumentation Ship  
AGMR Major Communications Relay Ship  
AGP Patrol Craft Tender  
AGR Radar Picket Ship  
AGOR Oceanographic Research Ship  
AGOS Surveillance Ship  
AGS Surveying Ship  
AGSC Coastal Surveying Ship  
AGSE Submarine Escort Ship (Blocking Vessel) (? Submarine and Special Warfare Support Vessel)
AGSL Satellite Launching Ship  
AGTR Technical Research Ship  
AH Hospital Ship  
AHP Evacuation Hospital Ship  
AK Cargo Ship  
AKD Cargo Dock Ship  
AKE Dry Cargo and Ammunition Ship  
AKI General Store Ship Issue  
AKL Light Cargo Ship  
AKN Net Cargo Ship  
AKR Vehicle Cargo Ship  
AKS Stores Issue Ship  
AKV Cargo Ship and Aircraft Ferry  
AL Lighter Ship  
ALS Auxiliary Lighter Ship  
AN Net Laying Ship  
ANL Net Laying Ship, Small  
AO Fleet Oiler  
AOE Fast Combat Support Ship  
AOG Gasoline Tanker  
AOR Replenishment Fleet Tanker  
AOT Transport Oiler  
AP Transport  
APB Self-Propelled Barracks Ship  
APc Coastal Transport  
APC Small Coastal Transport  
APF Administrative Flagship  
APG Support Gunnery Ship  
APH Evacuation Transport  
APM Mechanized Artillery Transport  
APN Non-Mechanized Artillery Transport  
APP Troop Barge, Class A  
APR Rescue Transport  
APV Transport and Aircraft Ferry  
ARb Base Repair Ship  
ARB Battle Damage Repair Ship  
ARC Cable Repairing Ship  
ARDC Concrete Auxiliary Repair Dock  
ARDM Medium Auxiliary Repair Dry Dock  
ARG Internal Combustion Engine Repair Ship  
ARH Heavy Hull Repair Ship  
ARL Repair Ship, Small  
ARM Heavy Machinery Repair Ship  
ARS Salvage Ship  
ARSD Salvage Lifting Ship  
ARST Salvage Craft Tender  
ARV Aircraft Repair Ship  
ARVA Aircraft Repair Ship, Aircraft  
ARVE Aircraft Repair Ship, Engine  
ARVH Aircraft Repair Ship, Helicopter  
AS Submarine Tender  
ASDV Auxiliary Swimmer Delivery Vehicle  
ASR Submarine Rescue Vessel  
AT Ocean Tug  
ATA Auxiliary Ocean Tug  
ATF Fleet Ocean Tug  
ATL Ocean Tug, Small (?)
ATO Auxiliary Ocean Tug, Old  
ATR Rescue Ocean Tug  
ATS Towing, Salvage, and Rescue Ship  
AVB Aviation Logistics Support Ship  
AVC Large Catapult Lighter  
AVM Guided Missile Ship  
AVP Small Seaplane Tender  
AVR Aircraft Research Vessel  
AVS Aviation Supply Ship  
AVT Auxiliary Aircraft Landing Training Ship  
AW Distilling Ship  
AWK Aircraft Rescue Vessel Water Tanker  
AZ Airship Tender  
EOD Explosive Ordinance Disposal  
EPF Expeditionary Fast Transport  
ESB Expeditionary Sea Base  
ESD Expeditionary Transfer Dock  
FDL Fast Deployment Logistics Ship  
HST High Speed Transport  
HSV Hight Speed Vessel  
IX Miscellaneous Unclassified  
MERC Multi-Use Explosive Ordinance Disposal Craft  
MPFUB Maritime Prepositioning Force Utility Boat  
SBX Mobile Radar Platform  
Yard Craft
APL Barracks Craft, Non Self-Propelled  
EYC Open Lighter, Experimental  
EYFN Covered Lighters, Experimental  
TLL Tank Lighter  
XMAP Sweeper Device  
YA Ash Lighter  
YAG Miscellaneous Auxiliary Service Craft  
YAGR Ocean Radar Station Ship  
YBD Bow Dock  
YC Open Lighter  
YCD Fueling Barge  
YCF Car Float  
YCK Open Cargo Lighter  
YCV Aircraft Transportation Lighter  
YD Floating Crane  
YDG Degaussing Vessels  
YDT Diving Tender  
YE Ammunition Lighter  
YFD Yard Floating Dry Dock  
YF Coverd Lighter, Self-Propelled  
YFB Ferry Boat or Launch  
YFN Covered Lighter, Non Self-Propelled  
YFNB Large Covered Lighter  
YFND Dry Dock Companion Craft  
YFNG Covered Lighter, Special Purpose  
YFNX Special Purpose Lighter  
YFP Floating Power Barge  
YFR Refrigerated Covered Lighter  
YFRT Range Tender  
YFT Torpedo Transportation Lighter  
YFU Harbor Utility Craft  
YG Garbage Lighter, Self-Propelled  
YGN Garbage Lighter, Non Self-Propelled  
YH Ambulance Boat  
YHB House Boat  
YHLC Salvage Lift Craft, Heavy  
YHT Scrow, Heating  
YLA Open Landing Lighter  
YLLC Salvage Lift Craft, Light  
YM Dredge  
YMD Mud Scow  
YMLC Salvage Lift Craft, Medium  
YMT Motor Tug  
YN Net Tender  
YNg Gate Craft  
YNT Net Tender, Tug  
YO Fuel Oil Barge  
YOG Gasoline Barge, Self-Propelled  
YOGN Gasoline Barge, Non Self-Propelled  
YON Fuel Oil Barge, Non Self-Propelled  
YOS Oil Storage Barge  
YP Patrol Craft, Training  
YPD Floating Pile Driver  
YPK Pontoon Stowage Barge  
YR Floating Workshop  
YRB Repair and Berthing Barge  
YRBM Repair, Berthing and Messing Barge  
YRBML Repair, Berthing and Messing Barge, Large (?)
YRC Submarine Rescue Chamber  
YRDH Floating Dry Dock Worskhop, Hull  
YRDM Floating Dry Dock Workshop, Machinery  
YRL Covered Lighter, Repair  
YRR Radiological Repair Barge  
YRST Salvage Craft Tender  
YS Stevedoring Barge  
YSD Seaplane Wrecking Derrick  
YSP Salvage Pontoon  
YSR Sludge Removal Barge  
YT Harbor Tug  
YTB Large Harbor Tug  
YTL Small Harbor Tug  
YTM Medium Harbor Tug  
YTT Torpedo Trials Craft  
YV Drone Aircraft Catapult Control Ship  
YVC Catapult Lighter  
YW Water Barge, Self-Propelled  
YWN Water Barge, Non Self-Propelled  
YWO Waste Oil Barge  
YWDN Water Distilling Barge  
YX Miscellanous Unclassified  


U.S. Coast Guard (1942-)

Until World War II, the US Coast Guard did not use a hull classification system for its larger, oceangoing ships which have traditionally been known in the service as "cutters" regardless of their size and armament (an exception was the lease of 25 US Navy destroyers during the prohibition era in the 1920s-30s that were given the CG hull symbol). This changed in February 1942 when it adopted the US Navy's hull classification system, albeit with a W prefix indicating that the vessel was in USCG use. On May 1st, 1965 the USCG adopted its own unique hull classification system which maintained the tradition of a W prefix but which otherwise referred to a ship's endurance at sea. The USCG hull designation system is largely based on acronyms and new ship descriptions frequently result in new hull symbols even when the ship's role is indentical to an earlier type. So for example, the new "national (or maritime) security cutters" of the Legend-class (WMSC) are indentical in role to the "high endurance cutters" of the Hamilton-class (WHEC) that they are replacing. Not all new cutter types get their own hull symbol: the modern Sentinel-class "fast response cutters" retain the WPB hull symbol of normal patrol boats.

Hull classifications
CG Destroyer (UN Navy lease) 25 destroyers loaned to USCG in 1924-34 only
WAGB Icebreaker  
WAGL Auxiliary Lighthouse Tender  
WAGO Oceanographic Vessel  
WAT Fleet Tug  
WAVP Seaplane Tender  
WDE Destroyer Escort  
WHEC High Endurance Cutter  
WIX USCGC Eagle Barque Sail training ship
WLB Ocean Buoy Tender  
WLBB Ocean Buoy Tender/Icebreaker  
WLM Coastal Buoy Tender  
WLI Inland Buoy Tender  
WLIC Inland Construction Tender  
WLR River Buoy Tender  
WMEC Medium Endurance Cutter  
WMSL Maritime Security Cutter, Large  
WPC Patrol Craft  
WPB Patrol Boat  
WPG Patrol Gunboat reclassified WHEC (1/5/1965)
WSC Submarine Chaser reclassified WMEC (1/5/1965)
WTGB Tug Boat (140 ft Icebreakers)  
WYTL Small Harbor Tug  
WYTM Medium Harbor Tug  


Sources: Naval Vessel Register, NavSource, NavWeaps

Last modified: 20 January 2023