Naval Compartment Identification Plate

This is a naval compartment identification plate, used aboard U.S. Navy ships to designate specific spaces.

4.25" x 2.25"

Breakdown of the inscription:

• "01-47-1" → Compartment designation:

  • 01 = first deck above the main deck.

  • 47 = at or near frame 47 (the ship’s structural frame location).

  • 1 = first compartment from the ship’s centerline (odd numbers = starboard side, even numbers = port side).

• "40MM AMM." → This space was designated for 40mm ammunition storage (ammo magazine). The 40mm Bofors gun was a widely used anti-aircraft and surface-defense weapon in the U.S. Navy during World War II and after.

• "A-0101-LM" → This is the Navy’s compartment classification code:

  • A = Ship’s ammunition (magazine) type of compartment.

  • 01 = deck level.

  • 01 = frame or longitudinal reference.

  • L = compartment use (Living, Ammunition, or in this case, specific to classification system).

  • M = magazine (specifically for ammunition).

Purpose:

This plate would have been mounted on the bulkhead or hatch of a magazine where 40mm ammunition was stored. These markings helped sailors and damage control parties quickly identify what was in each compartment—critical during emergencies like fires or flooding.

So, this is a WWII-era (or slightly later) U.S. Navy ship’s 40mm ammunition magazine identification plate.