crane was built between 1944 and 1951 on the Fitting Out Wharf at Garden Island. The electrically powered crane had a radius of and a total height of . The electrical and mechanical equipment was sourced from England, while the steel frame was fabricated in Sydney. Although officially declared completed in January 1952, the crane was operational from March 1951. The crane's primary purpose was the removal and installation of warship gun turrets, although it was regularly used for other machinery and loads, and had a lifting capacity of up to . It was last used in 1996. In August 2013, the Federal Government announced the removal of the hammerhead crane, at an estimated cost of $10.3 million. Other options, such as preserving the crane as a heritage structure and tourist attraction, restoring it to working order, or converting it to a new purpose, were ruled out due to cost and the risk to security at the naval base. The removal was also seen as necessary to free up wharf space for the Canberra-class amphibious warfare ships. The Hammerhead Crane was the largest crane in the southern hemisphere on completion, and as of 2005, was still the largest crane in Australia. At the time of its demolition, it was only 15 cranes of that style worldwide. Removal was completed by November 2014, with some components preserved for heritage purposes. Tunnel system There is a tunnel system under Garden Island that was once used by the Royal Australian Navy. Within this tunnel system was a power station, offices and air raid shelters. This tunnel complex also had a command centre. Other tunnels also exist which headed further in towards Kings Cross. The tunnels were used to move guns from one side of the island to the other. There are also older tunnels that were used to transport ammunition. The tunnels are now used for electrical wiring and communications. The island also has a pit that was built in the 1800s and was used as a storage facility in case the island was ever attacked. The entrance to this pit has now been sealed. Current usage Dockyard The dockyard facilities are today leased to and operated by the defence contractor Thales Australia, a part of the international Thales Group. They are used to service naval and civilian vessels. Wharves The various wharves that line Garden Island remain under the control of the