HMS Tireless was the third of the Trafalgar class hunter-killer nuclear submarines. These are not nuclear armed but nuclear powered and conventionally armed.

Tireless was launched in 1985 and, at  28 years old, was due to be decommissioned this year. However, her service was extended for another four years due to the delay in the rollout of the new Astute class submarines.

Ten days ago, Tireless was taking part in a training exercise for new officers off the west coast, when a coolant leak developed within its sealed reactor unit. The Ministry of Defence has said that no risk was involved  to the public the environment or the crew.

Tireless was ordered back to the Faslane naval base on the Clyde where engineers inspected the leak; and then returned to her home base at Devonport.

She is said to face up to 10 months in dry dock while repair work is carried out.

Tireless is most famous for a series of troubling incidents.

She collided with an iceberg at 60 metres down on 13th May 2003 [it would have been the 13th]. This was the first return of the navy to under-ice operations since 1996. Neither her passive sonar nor other onboard sensors had given any warning of the proximity of the iceberg.  Tireless’s bow was forced down 9 degrees and she subsequently broke free of the iceberg at a depth of 78 metres. Some damage was done to her upper section.

She suffered an earlier leak  of her reactor coolant , in May 2000 in the Mediterranean. This saw her nuclear propulsion system shut down, with backup diesel power getting her into Gibraltar. She spent a year there under extensive repairs,  becoming the focus of serious diplomatic strain.

In March 2007, on deployment back in the Arctic, it was Tireless that had an internal explosion  in her forward section – later found to be caused by a defective or obsolete oxygen candle.This killed two of her crew – Leading Operator Mechanic Paul McCann; and Operator Maintainer (Weapons Submariner) 2 Anthony Huntrod.

Following the current incident, there is real concert that the cost of the failures experienced by  the new Astute hunter-killers – in forcing the extension of the lives of ageing Trafagar class submarines like Tireless – may be asking the impossible or the dangerous.

The problems in with commissioning of the Astute submarines are having a knock on effect on the nuclear safety of the older Tralfalgar hunter-killers that were due for decommissioned.

This latest reactor coolant leak is seen as potential evidence that this ship is actually reaching the end of her life. It may be that she has to be decommissioned and will not emerge from the extensive repair period now necessary.

Her preceding two siblings – class leader, HMS Trafalgar and HMS Turbulent have already been decommissioned, Tralfalgar in 2009 and Turbulent in JUly last year, 2012.

The current incident has reduced the hunter-killer fleet to a maximum of five instead of the recommended seven plus a spare needed to carry out vital duties, including protecting the UK’s Trident missile-carrying Vanguard submarines.

Of those five, Astute, Britain’s brand new £1.2billion attack submarine which – gloriously – ran aground in 2010 for the ultimate photo opportunity – just beside the Skye Bridge –  is still not fully operational. One other, possibly two, are in maintenance.

This latest incident comes just weeks after the Clyde-based Trident submarine,  HMS Vigilant ,was stranded in the US after its rudder broke, just after her £350million refit.

The leak will also fuel the heated political debate about nuclear submarines operating in Scottish waters.

Last night, local MSP, Michael Russell MSP for Argyll and Bute, called on the Ministry of Defence to clarify exactly what had happened. He said: “This is the latest in a long line of alarming incidents involving nuclear submarines off the coast of Scotland. ‘

Andy Smith of the UK National Defence Association, says: ‘The problems with HMS Tireless illustrate the folly of trying to have ‘defence on the cheap’ and failing to upgrade or replace equipment due to political short-sightedness and a defence policy dictated by the treasury rather than the military.’

Source – For Argyll