Factbox - Britain's Astute class submarines

(Reuters) - The British nuclear-powered submarine HMS Astute ran aground off the coast of northwest Scotland on Friday, a Ministry of Defense (MoD) spokesman said.

Crew stand on the deck of the Royal Navy nuclear-powered submarine HMS Astute near the Skye bridge off the Isle of Skye, northwest Scotland October 22, 2010. REUTERS/David Moir

Commissioned into the navy in August, The submarine was undergoing trials before becoming fully operational.

Here are some facts about the submarine and some other incidents involving Britain’s submarine fleet:

* The vessel is part of a new Astute-class of submarine, made by BAE Systems, and Britain plans to buy a total of seven.

* Astute’s role as an undersea hunter-killer relies on stealth. It performs a range of tasks including intelligence gathering, anti-submarine and anti-surface vessel warfare.

* The submarine carries six 21-inch (533mm) tubes for Spearfish torpedoes and Tomahawk cruise missiles -- totaling 38 weapons -- capable of delivering pin-point strikes 2,000 km from the coast.

* The nuclear reactor and four turbines on board Astute are capable of generating tens of megawatts of power, and less than a single watt of power is radiated into the sea. Astute is designed not to require refueling throughout her full service life.

* Key Figures:

Length Overall: 97 meters

Displacement: 7,800 tonnes

Design Diving Depth: over 300 metres

Submerged Speed: around 30 knots

Patrol Endurance: 90 days

Crew: 84 (12 officers)


2002 - The nuclear-powered submarine HMS Trafalgar struck the bottom of the sea at more than 14 knots off the Isle of Skye after basic navigational errors during a training exercise.

2007 - Two British sailors were killed and another injured in an accident on HMS Tireless, a nuclear-powered submarine, on exercise in the Arctic. The Ministry of Defense said the nuclear reactor on board was not affected.

2008 - HMS Superb hit a submerged pinnacle after passing through the Suez Canal, forcing it to surface.

-- Its nuclear reactor was unaffected and there was no water leakage or environmental impact, defense officials said. There were no injuries among the 112-strong crew. The Swiftsure-class attack submarine was about 80 miles south of Suez when the incident happened.

2009 - Two submarines -- France’s Le Triomphant and Britain’s HMS Vanguard -- collided at very low speed, having failed to detect each other because they were designed to be silent and invisible.

Sources: Reuters/Jane’s Fighting Ships/BAE Systems:

Writing by David Cutler, London Editorial Reference Unit