Los Angeles class nuclear submarine USS Pittsburgh has arrived at Faslane in Scotland for a routine visit.

USS Pittsburgh is among the oldest serving nuclear submarines in service with the US Navy. The sub was first commissioned in 1985 and may be decommissioned in 2019.

Crewed by 12 officers and 98 enlisted sailors, USS Pittsburgh is part of the US Atlantic Fleet. The vessel has a submerged full displacement of 6,193 tons.

The vessel participated in strikes on Iraq in 1991 during Operation Desert Storm using submarine-launched Tomahawk cruise missiles. It returned in early 2003 to participate in strikes as part of Operation Iraqi Freedom.

HMNB Clyde is sited at Faslane in the west of Scotland not far from Glasgow, one of Britain’s largest cities. It’s one of three operating bases in the United Kingdom for the Royal Navy, the others being HMNB Devonport and HMNB Portsmouth. It is best known as the home of Britain’s nuclear weapons, in the form of nuclear submarines armed with Trident missiles.

Faslane was first constructed and used as a base in World War II. During the 1960s, the British Government began negotiating the Polaris Sales Agreement with the United States regarding the purchase of a Polaris missile system to fire British-built nuclear weapons from five specially constructed submarines. In the end, only four were constructed; HMS Resolution, HMS Repulse, HMS Renown and HMS Revenge. These four submarines were permanently based at Faslane.

Faslane itself was chosen to host these vessels at the height of the Cold War because of its geographic position, which forms a bastion on the relatively secluded but deep and easily navigable Gare Loch and Firth of Clyde on the west coast of Scotland. This position provides for rapid and stealthy access through the North Channel to the submarine patrolling areas in the North Atlantic.