Just as a town or city has a system using street signs and addresses to help you find your way around, so does a Navy ship. Each space in a Navy vessel has a unique identifier that consists of a yellow rectangle with black letters and numbers, known as the bullseye. It will have several lines of information, with the topmost line, made up of numbers and letters, providing location information. For example: 4–95–3–M.
For each compartment, the numbers and letters will differ, but the format will not. That format tells you the following: