The Cockatoo Island Dockyard was a major dockyard in Sydney, Australia, based on Cockatoo Island. The dockyard was established in 1857 to maintain Royal Navy warships. It later built and repaired military and battle ships, and played a key role in sustaining the Royal Australian Navy. The dockyard was closed in 1991, and its remnants are heritage listed as the Cockatoo Island Industrial Conservation Area. Colonial ownership It was established by the colonial Government of New South Wales, commencing operations in December 1857 with the opening of Fitzroy Dock. Planning had begun as early as May 1846, when Governor George Gipps had recommended the construction of a dry dock at Cockatoo Island to the British government to service Royal Navy vessels. Construction had begun in 1851, with Captain Gother Mann as engineer-in-chief, and taken six years. It was known as the Government Dockyard – Biloela while in colonial control. Shipbuilding facilities, such as slipways and workshops, were also established, and the dockyard produced small vessels for the colonial government, in addition to its role servicing British government vessels. It was initially administered by the superintendent of the adjacent prison, but was operated by the Department of Harbours and Rivers from 1864. The main machine workshop was upgraded in the same year. Fitzroy Dock was lengthened from to 1870, and extended for a second and final time to in 1880. Numerous buildings were added to the site during the 1880s, including a Pump House, stores and accommodation for new machinery. It became apparent as early as 1870 that a larger dock would be needed due to the increasing size of ships, and Sutherland Dock was built from 1882 to 1890 at a cost of £267,825. Sutherland Dock, at long and wide, was said to be the largest dock in the world at completion. Its size allowed it to cater to the larger Royal Navy vessels. Facilities at the shipyard were expanded significantly in the 1890s following the opening of Sutherland Dock, taking up a larger proportion of Cockatoo Island. Although the Federation of Australia took place in 1901, the New South Wales government remained in ownership of the dockyard. The dockyard was again extensively upgraded between 1904 and 1908, with the construction of a steel foundry, extension of existing workshops, construction of two new slipways, and additional steel-working facilities and cantilevered cranes. The Royal Australian Navy was established in 1911. ,