Officers reprimanded for crashing British nuclear sub

March 17, 2010

A British Royal Navy commander was reprimanded on Monday by a court martial, after pleading guilty to "failing to ensure the safe direction" of the submarine HMS Superb. Commander Steven Drysdale was in charge of the nuclear-powered submarine in May 2008, when it struck a rock pinnacle 132 metres below the surface. A navigation chart showed the pinnacle, but Drysdale said that he had misread its depth as 732 metres.

Officer of the Watch Lieutenant-Commander Andrew Cutler and Navigating Officer Lieutenant Lee Blair were also reprimanded for their part in the incident by the court martial, held at the HMS Nelson centre at Portsmouth naval base.

The £32 million submarine was in the Red Sea, heading for the Persian Gulf, and was suffering from technical problems at the time which were slowing it down. The officers decided to dive from 100m to 250m, which would allow them to travel faster and reach their destination on time.

According to prosecutor Captain Stuart Crozier: "The three defendants all looked at the chart and the sub was taken to 250m. No thorough check was made to establish whether this depth was safe from obstacles."

Lieutenant-Commander Cutler then realised that a change to the route could shorten it. “On assessing the chart, Officer of the Watch Cutler saw he could cut the corner of a dog-leg, saving about three to four miles," said Crozier. "He then instructed the plot officer to draw a new line on the chart. However Lieutenant-Commander Cutler did not check the depth around this new track."

"Unfortunately, with the sub now dived to 250m, this new track went directly over a pinnacle which showed only 132m of available depth."

The new route was plotted directly over the pinnacle on the chart, and the court martial was told that this made it harder to spot the error. None of the officers, including Commander Drysdale, realised that they had put the vessel on a collision course.

HMS Superb struck the pinnacle at 10.01 on May 26, suffering damage to its bow and sonar equipment. There were no casualties, but the submarine was forced to abandon its mission and return to the United Kingdom. It was decommissioned in September 2008, though the Ministry of Defence said that this was not due to the accident.

Commander Alison Towler, representing Drysdale, said that he accepted full responsibility and had "deep remorse and regret" over the incident. "He believes that due to the surrounding information he simply misread 132m as 732m" she said. "It was only later that he realised the plot officer had drawn the sub’s new transit straight through the pinnacle, which made it even harder for it to be seen."

Navigating Officer Blair also pleaded guilty to failing to take into account all the dangers in or near the planned movements, and Officer of the Watch Cutler pleaded guilty to failing to supervise the plot officer adequately. All three officers will continue to serve in the Navy, but Drysdale has been moved to a desk job and will not be taking up the position in Washington DC he had planned to.

Captain Philip Warwick, president of the court martial board, told the three: "It was indeed fortunate that no one was hurt and we note that the submarine could not complete its deployment in full. The failings were unacceptable and we take an extremely dim view of them."

The Royal Navy has since brought in new procedures on submarines to prevent a repeat of the incident, requiring that all depths are rechecked when plotting a new route.