Devonshire Dock Hall

Devonshire Dock Hall
Devonshire Dock Hall viewed from Channelside Haven in 2010
General information
Type	Shipbuilding hall
Location	Barrow-in-Furness, England, United Kingdom
Coordinates	54°06′37″N 3°14′15″W / 54.1104°N 3.2374°W / 54.1104; -3.2374
Construction started	1982
Completed	1986
Owner	BAE Systems Maritime – Submarines
Technical details
Structural system	Steel frame
Floor area	25,000 square metres (270,000 sq ft)
Design and construction
Architect	Alfred McAlpine
Main contractor	Alfred McAlpine

Devonshire Dock Hall (often abbreviated to DDH) is a large indoor shipbuilding and assembly complex that forms part of the BAE Systems shipyard in the Barrow Island area of Barrow-in-Furness, Cumbria, England.

Constructed between 1982 and 1986 by Alfred McAlpine plc for Vickers Shipbuilding and Engineering, DDH was built on land that was created by infilling part of Devonshire Dock with 2.4 million tonnes of sand pumped from nearby Roosecote Sands. The purpose of the indoor shipbuilding facility was to protect vessels from external weather conditions and prevent satellites from photographing secret technologies involved. In the late 1980s and early 1990s it was known colloquially as "Maggie's Farm" in reference to the then Prime Minister Margaret Thatcher, who opened the facility, and whose Conservative Party government were upgrading the UK's submarine-launched nuclear weapons from Polaris to the Trident system on board the Vanguard-class boats. DDH provides a controlled environment for ship and submarine assembly, and avoids the difficulties caused by building on the slope of traditional slipways. Outside the hall, a 24,300 tonne capacity shiplift allows completed vessels to be lowered into the water independently of the tide. Vessels can also be lifted out of the water and transferred to the hall. The shiplift was the largest in the world upon completion. The first use of the DDH was for construction of the Vanguard-class submarines (Vanguard, Victorious, Vigilant and Vengeance). The shipyard is currently constructing the Astute-class submarines the first three of which were launched in 2007, 2011 and 2014. As of 2014, the Royal Navy submarines Audacious, Anson and Agamemnon are all under construction inside Devonshire Dock Hall.