A DEVONPORT-based nuclear-powered submarine was three miles

off course when she hit the seabed at 22 knots, new files

released by the Ministry of Defence (MoD) have revealed.

HMS Triumph, one of seven Trafalgar- class boats based in

the Westcountry, was taking part in a Submarine Command Course

when the accident happened on November 19, 2000.

Ten days later, HMS Victorious – one of four submarines that

carries Britain's nuclear weapons deterrent – also grounded

after leaving HM Naval Base Clyde.

The official report into the Triumph accident blamed

inexperience among officers on watch, while nearly a third of

the crew had been drafted in from other T-boats.

“In the board's opinion, considerable risk was taken in

diluting the ship's company in order to manage leave,

appointing, drafting and morale in Triumph,” the report

said.

“This was clearly a questionable step, particularly in view

of the demanding operations inherent in Submarine Command

Course running.”

At the time, the MoD said the submarine had suffered

“superficial damage”, which cost just £6,000 to repair. It said

the boat had “made glancing contact with soft sand and shells

on a shelving seabed when under way submerged”.

After the impact off the west coast of Scotland, it surfaced

immediately. Checks proved it was further away from where

officers thought.

“The grounding occurred because the submarine's true

position was some 2.6 nautical miles [or three statute miles]

further east than that plotted and when evidence that the

navigational position was in error was obtained, it was not

acted upon,” the board concluded.

Two lieutenant commanders were reprimanded at court martial

in December 2001.

The MoD also released files on a crash involving HMS

Victorious on November 29, 2000. It grounded on Skelmorlie Bank

in the Clyde estuary.

“The primary cause of the grounding was a failure of

standard navigational practise and a lack of awareness among

all members of the navigation team of the increased danger to

safe navigation as soon as the submarine had deviated from its

pre-briefed navigational plan,” the report concluded.

In May, the MoD finally admitted that Devonport-based HMS

Tireless did hit an iceberg during exercises in the Arctic in

May 2003. At the time, it refused to comment on the precise

nature of the accident, merely stating that the vessel had a

“chance contact with a free-floating object whilst she was

operating submerged”.

A Board of Inquiry report, again released under the Freedom

of Information Act, confirmed the boat had hit an iceberg while

63m below the surface. No-one was blamed.