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General Order No. 541 (1920)

Related Resources:

Ship Nomenclature and Ship Types:
ONI Official Definitions (1919):
Classifications of Naval Ships and Craft, SECNAVINST 5030.1E (1968):
Classifications of Naval Ships and Craft, SECNAVINST 5030.1L (1993):
Classifications of Naval Ships and Craft, SECNAVINST 5030.8 (2006):


Following World War I, and the confusion experienced in mailing correspondence and shipping spare parts to ships, Acting Secretary of the Navy Robert E. Coontz approved a standardized system of alpha-numeric symbols to identify ship types (e.g., BB for battleship, DD for destroyer, DM for light mine layer, AD for destroyer tender). Linked with a consecutive number, the use of which now became general for all types of naval ships, these classification symbols provided positive and individual identification of both named and unnamed ships, many of which might not be readily identifiable by name alone.

Note that while the first letter of the ship type indicates the type designation, and the second letter indicates sub-type (such as CL for light cruiser), this is not always the case as shown by the designation DD, which simply stands for "destroyer" and ODD, which stands for "old destroyer."


GENERAL ORDER
No. 541
NAVY DEPARTMENT,
OFFICE OF NAVAL OPERATIONS,
Washington, D.C., July 17,1920.

STANDARD NOMENCLATURE FOR NAVAL VESSELS

1. In order to provide a standard nomenclature for types and classes of vessels comprised in the U.S. Navy, as well as a standard system of identification numbers which may be used, when pertinent, in correspondence and for the marking of spare parts and the like, there will be published annually a "Ships' Data Book," prepared by the Bureau of Construction and Repair and approved by the Secretary of the Navy, which will contain the standard nomenclature, identification numbers, and abbreviations for naval vessels. Such nomenclature, numbers, and abbreviations shall be used in official correspondence and communications and for the marking of spare parts.

In advance of the issue of the next "Ships' Data Book," which will contain the approved standard designations, including identification numbers of all naval vessels, the following detailed list shows the names of types, type designations, names of classes, and class designations to be included in future editions:

Type Type Designation Class Class Designation
Battleship B Battleship, first line
Battleship, second line
Monitor, first line
Monitor, second line
BB
BB
BM
OBM
Cruiser C Battle cruiser, first line
Battle cruiser, second line
Cruiser, first line
Cruiser, second line
Light cruiser, first line
Light cruiser, second line
Aircraft carrier, first line
Aircraft carrier, second line
Minelayer, first line
Minelayer, second line
CC
OCC
CA
OCA
CL
OCL
CV
OCV
CM
OCM
Destroyer D Destroyer, first line
Destroyer, second line
Destroyer leader
Light minelayer
DD
ODD
DL
DM
Submarine S Submarine, first line
Submarine, second line
Fleet submarine, first line
Fleet submarine, second line
Cruiser submarine
Minelaying submarine
SS
OSS
SF
OSF
SC
SM
Patrol Vessel P Eagle
Submarine chaser
Gunboat
Yacht
PE
PC
PG
PY
Auxiliary A Destroyer tender
Submarine tender
Lighter-than-air craft tender
Heavier-than-air craft tender
Repair ship
Storeship
Collier
Oiler
Ammunition ship
Cargo ship
Transport
Hospital ship
Fleet tug
Minesweeper
Auxiliaries, miscellaneous
AD
AS
AZ
AV
AR
AF
AC
AO
AE
AK
AP
AH
AT
AM
AG
Lighter-than-Air Z Rigid dirigible
Nonrigid dirigible
Kite balloon
ZR
ZN
ZK
Heavier-than-Air V Fighting plane
Observation plane
Scouting plane
Patrol plane
Torpedo and bombing plane
VF
VO
VS
VP
VT
District Craft Y Ash lighter
Ambulance boat
Ammunition lighter
Coal barge
Car float
Fueling barge
Floating derrick
Dredge
Freight lighter
Garbage lighter
Heating scow
Mud scow
Oil barge
Ferry boat and launch
Piledriver
Stevedoring barge
Torpedo testing barge
Water barge
Floating workshop
Seaplane barge
District tug
District patrol
YA
YH
YE
YC
YCF
YCD
YD
YM
YF
YG
YHT
YMD
YO
YFB
YPD
YS
YTT
YW
YR
YV
YT
YP

NOTE.--Vessels taken over temporarily by the Navy will have will have designating letters and numbers assigned according to the type and class to which they belong. The Identification numbers for such vessels will always be preceded by the letter "X," Indicating the temporary nature of the assignment; for example, if there were already four heavier-than-air craft tenders In the Navy and a fifth were taken in temporarily, It would be given an identification number XAV5. The number "5" should not be again used for vessels of this class; the next heavier-than-air craft tender built or taken over would be "6."

R. E. COONTZ,
Acting Secretary of the Navy.


 Dr. Timothy L. Francis, 10 August 2007