Ship fitters at Mare Island Naval Shipyard, 1943

Ship fitters at the Mare Island Naval Shipyard, California, circa 1943.

During World War II, base facilities included a hospital, ammunition depot, paint and rubber testing laboratories, and schools for firefighters, opticians, and anti-submarine attack during World War II. It reached peak capacity for shipbuilding, repair, overhaul, and maintenance of many different kinds of seagoing vessels including both surface combatants and submarines. Up to 50,000 workers were employed.