Damage to a dive-computer linked to a closed-circuit rebreather caused the death of an experienced technical diver, an inquest has heard.
For the second time in a week, Plymouth Coroners’ Court has conducted an inquest into a fatal incident involving Plymouth Sound Divers club last summer. Divernet reported on 18 February on the inquiry into the death of Richard Fletcher, 57, on a shore dive.
Peter Dahle, 56, failed to resurface from a deep dive on 3 August, an incident reported at the time on Divernet. He was diving the East Point, the wreck of a cargo steamship sunk in 1917, which lies at a maximum depth of 68m about five miles off Eddystone Lighthouse.
Dahle, an ex-Royal Marine and firefighter from Plymouth, was diving with other members of BSAC branch Plymouth Sound Divers, according to Devon Live and BBC reports on the inquest.
Club diving officer Will Schwarz, who organised the dive, had driven out to the wreck-site with four other divers, including Dahle. Dahle had entered the water in a group of three for what was expected to be a two-hour dive. Rebreather and buddy checks were reported to have been completed as usual.
Paul Downs, one of the divers with Dahle, described him to the court as a “really safety-conscious diver”. He said that Dahle had helped him when he started to panic after becoming entangled in netting during the shotline descent.
On reaching the wreck, Dahle had realised that the computer linked to his rebreather wasn’t working, and although this was not regarded as a serious problem at the time the three divers agreed to begin their staged ascent together at that point.
However, by the time Downs reached the 6m mark he said that he had lost sight of Dahle, and assumed that he had already surfaced.
When Downs surfaced he and those on the boat had seen Dahle’s SMB, which he would have sent up from between 20m and 6m, close to another one, so assumed that he was with the other diver. Downs went over to the buoy but couldn’t see Dahle below. A Mayday call went out and a search operation was launched.
The inquest heard that during the ascent a crack on Dahle’s computer screen had led to water flooding the handset. This would have affected the oxygen supply to his rebreather, with hypoxia causing him to gradually lose consciousness by the time he reached his 6m stop.
23 February 2020
Coroner’s officer Graham Higginson said that the crack was likely to have been caused by poor maintenance rather than damage sustained while disentangling Downs from the net. Dahle would have been unaware of the effect on his oxygen supply.
A pathologist declared that Dahle had been relatively fit and gave the cause of death as accidental drowning, hypoxia and water entering the rebreather system.
Returning a verdict of accidental death, Assistant Coroner Stephen Covell said that the club might wish to review its training and buddy system in light of Dahle’s death.
