User:Saberwyn/Captain Cook Graving Dock

The Captain Cook Graving Dock is a drydock

Design and construction

 * Prior to World War II, the largest graving dock in Sydney was Mort's Dock, a privately owned shipyard in Balmain.
 * The nearest sizable naval graving dock was at Singapore Naval Base; an 8,000 nmi round trip for a potentially damaged warship.


 * In 1938, the Australian cabinet approved the idea of building a large naval graving dock.
 * The cost of construction was predicted at around A£3 million.
 * A far cheaper alternative, a second-hand floating drydock being sold by Southern Railway was considered early on. Despite the A£175,000 cost, the acquisition was opposed by Admiral Ragnar Colvin, as it would be expensive and difficult to maintain, would be unable to accommodate the draught of ships being acquired for the RAN, and would be incredibly risky to tow from England to Australia.


 * Three sites were considered: two in Sydney Harbour (one at Potts Point, the other near the Sydney Harbour Bridge), and the third in Adelaide. Potts Point was chosen as the cheapest location.
 * The dock itself would be built by the reclamation of 30 acre of land, connecting Garden Island to the mainland.


 * By September 1944, work had been completed to the stage where initial flooding tests could occur.

Size and capability

 * The dock is 1,139 ft long, with a width of 147 ft.
 * The dock is 45 ft deep at spring tide.


 * When filled, the dock has a capacity of 50,000,000 impgal. The dock can be drained in a four hour period through the use of three 60 in centrifugal pumps (each with a discharge capacity around 70,500 impgal per minute).

Usage

 * On 2 March 1945, the British aircraft carrier HMS Illustrious (87) underwent an emergency docking. Although the drydock was not due to open for another three weeks, the advanced state of building made the docking possible.


 * The Captain Cook Graving Dock was formally opened when? by Prince Henry, Duke of Gloucester in his role as the Governor-General of Australia. The ribbon cutting was performed by the bow of the frigate HMAS Lachlan (K364).


 * During the first year of operations, the drydock received the British battleship HMS Anson (79); the 45,360-ton displacement warship is the largest vessel to use the dock.