Before World War II, Mare Island had been in a continual state of up-building. By 1941, new projects included improvements to the central power plant, a new pattern storage building, a large foundry, machine shop, magazine building, paint shop, new administration building, and a huge storehouse. The yard was expected to be able to repair and paint six to eight large naval vessels at a time. Several finger piers had recently been built, as well as a new shipbuilding wharf, adding one and a berth. It employed 5593 workers at the beginning of 1939, and rapidly increased to 18,500 by May 1941, with a monthly payroll of $3.5 million. In 1941, the drafting department had expanded to three buildings accommodating over 400 naval architects, engineers and draftsmen. The hospital had 584 beds. During World War II, the shipyard employed up to 50,000 workers.