In 1913 Cockatoo Island become the Commonwealth Naval Dockyard. In 1933 it was leased to the Cockatoo Island Docks and Engineering Company Ltd. During World War II, Cockatoo Island's importance to the Allies increased after Singapore and its shipyards were captured by the Japanese. At least 20 ships were built during the war. The dockyard continued to build both naval and commercial vessels until it closed in 1992.