Simplify the following text for a Grade 9 native English-speaking person.
Original: In 1913 Cockatoo Island become the Commonwealth Naval Dockyard , but in 1933 it was leased to the Cockatoo Island Docks & Engineering Company Ltd. .
Simplified: In 1913 Cockatoo Island become the Commonwealth Naval Dockyard . In 1933 it was leased to the Cockatoo Island Docks and Engineering Company Ltd. .