Battleship New Jersey Amateur Radio Station (BNJARS)

Compartment Numbering System

After 1949, each compartment was given a number indicating that compartment’s deck number, frame number, relation to the centerline of the ship, and usage. A hyphen separates the numbers and letters representing each type of information. The following is an example of a compartment number and what each part of the number represents:

Deck Number – Frame Number – Centerline – Usage


3 – third deck

75 – forward boundary at or immediately abaft of frame 75

4 – second compartment outboard of CL to port

M – ammunition compartment

DECK NUMBER – The main deck is deck number 1. The first deck or horizontal division below the main deck is number 2; the second below, number 3; and so forth. If a compartment extends down to the shell of the ship, the number assigned the bottom compartment is used. The first horizontal division above the main deck is number 01, the second above 02, and so on. The deck number, indicating its vertical position within the ship, becomes the first part of the compartment number.

FRAME NUMBER – The frame number at the foremost bulkhead of the enclosing boundary of a compartment is its frame location number. When a forward boundary lies between frames, the frame number forward is used. Fractional numbers are used only when frame spacing exceeds 4 feet.

RELATION TO CENTERLINE – Compartments through which the centerline of the ship passes carry the number 0 in the third part of the compartment number. Compartments located completely to starboard of the centerline have odd numbers; those completely to port bear even numbers. Two or more compartments that have the same deck and frame number and are entirely starboard or entirely port of the centerline have consecutively higher odd or even numbers, as the case may be. They are numbered from the centerline outboard. For example, the first compartment outboard of the centerline to starboard is 1; the second, 3; and so on. Similarly, the first compartment outboard of the centerline to port is 2; the second, 4; and so on.

COMPARTMENT USAGE – The fourth and last part of the compartment number is a capital letter that identifies the assigned primary usage of the compartment. Since most ships do not consider a secondary usage of compartments, they identify them by a single letter only. However, dry and liquid cargo ships do not follow this practice. These ships use a double-letter identification to designate compartments assigned to cargo carrying. Ships assign letter identifications as follows:

Code Category Usage
A Dry stowage Storerooms, issue rooms, refrigerated spaces
C Ship control and fire control operating spaces Plotting rooms, CIC, radio, radar, sonar operating spaces, pilothouse
E Engineering spaces Main propulsion spaces; pump, generator, and windlass rooms
F Oil stowage Fuel oil, diesel oil, and lubricating oil tanks
G Gasoline stowage Gasoline tank compartments, cofferdams, trunks, and pump rooms
J JP-5 tanks Aircraft fuel stowage
K Chemicals and dangerous materials Stowage of chemicals and semi-safe and dangerous materials, except oil and gasoline tanks
L Living spaces Berthing and messing spaces, medical and dental areas, and passageways
M Ammunition Stowage and handling
Q Spaces not otherwise covered Ship’s offices, laundry rooms, galleys, pantries, and wiring trunks
T Vertical access trunks  
V Voids Cofferdam compartments, other than gasoline; void wing compartments
W Water stowage Compartments storing water, including bilge, sump, and peak tanks
AA, FF, and GG Spaces used to carry cargo.  

Adapted from: Naval Orientation, NAVEDTRA 12966, July 1991 (0502-LP-213-4100)

See the USS New Jersey Compartment List (for communications related spaces)

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