In the December 2018 “Bluejacket’s Manual,” we explored finding one’s way around a Navy ship. That system of compartment identification only came into practice in 1949. Ships built before that time used a different method of identifying compartments and spaces.
In the pre-1949 system, each compartment was labeled with a formatted designation, such as:
The first letter gave a rough estimation of the compartment’s location fore and aft. That letter was always A, B, C, or D. Many ships did not include the “D” designation, which will be explained later. We will first consider a ship using only the first three letters, which divided the vessel into three sections, “A” being the forwardmost, “C” being the aftermost, and “B” comprising those compartments amidships.