Following America’s involvement in World War I, the Navy built its largest foundry in Building 20 in 1919. Today, the foundry and supporting buildings comprise the Naval Foundry and Propeller Center, which has provided foundry-made parts for nearly every ship and submarine built or overhauled at the Shipyard. At its peak in the 1940s, foundry operations had separate functions in 15 buildings constructed between 1913 and 1944. Adjacent buildings included the Machinery Repair Shop, Electrical Shop, Turret Shop, Lumber Storehouse, Material Assembly Shop, Radio and Sounding Radar Laboratory, and Humidity Testing. The electricians and technicians there could handle any job the Navy required. During World War II, the facility produced over 5,500 propellers of various sizes and today continues to provide propellers and precision castings for the Navy’s fleet.