Royal Navy incompetence put an Irish trawler crew at risk after one of its submarines became snagged in a net and nearly capsized the ship.
The nuclear-powered sub was sailing out of Faslane on the Clyde in April 2015 when it snagged the Karen's fishing gear between Ardglass and the Isle of Man
The Irish trawler Karen, which had four crew aboard, was pulled backwards and under the water for 30 seconds before the net snapped.
Commanders were unaware of the collision until three hours later after they failed to realise they were passing beneath a fishing vessel with nets rather than a merchant cargo or passenger ship, the Marine Accident Investigation Branch (MAIB) report said.
"Officers did not detect the sonar noise associated with trawling and did not know they had snagged the Karen until three hours later so did not surface immediately to help. Part of the prawn trawler’s deck had to be lifted and another section was ripped off," says the report.
Chief Inspector of Marine Accidents criticises Royal Navy's 'reluctance' to engage in an investigation into the collision between a dived Royal Navy submarine and the trawler Karen, east of Ardglass, Northern Ireland
"The accident happened because of insufficient passage planning by the submarine's command team and their failure to follow guidance on fishing vessel avoidance. Had its trawl warps not parted, it is almost inevitable that Karen would have capsized and sunk; the collision also presented a very significant risk to the submarine," says the report.
The report recommends the Royal Navy reviews
training and procedures. It said it should also provide reassurances to defence ministers and the fishing industry that lessons have been learned.