An investigation has been launched after a Royal Navy submarine was involved in a ‘close quarters’ incident with a roll-on roll-off ferry in the Irish Sea, the United Kingdom’s Marine Accident Investigation Branch said on Monday, January 21.
The November 6 incident which did not receive media coverage at the time involved the Stena Line ferry MS Stena Superfast VII, which is capable of carrying around 660 vehicles and 1,300 passengers and travels between Belfast in Northern Ireland and Cairnryan in Scotland.
The Royal Navy would not confirm which of its 10 submarines was involved. All are nuclear powered but only the four Vanguard-class boats carry Trident 2 D5 nuclear missiles.
“In November, we were notified of a close-quarters incident between the ro-ro (roll-on/roll-off) ferry Stena Superfast VII and a submarine operating at periscope depth,” the MAIB said in a release
“We have carried out a preliminary assessment of the evidence in this case and the Chief Inspector of Marine Accidents has decided to open a safety investigation. The investigation is being conducted with the full co-operation of the Royal Navy,” MAIB said.
MAIB noted the decision to start an investigation was declared on January 21.
A Royal Navy spokesperson confirmed “the sighting of a Royal Navy submarine between Belfast and Stranraer” on November 6.
A Stena spokesperson said the submerged submarine “came into close proximity” with the Stena Superfast VII during a scheduled crossing between Cairnryan and Belfast.
In 2015, the U.K. Ministry of Defence admitted a Royal Navy submarine dragged a trawler backwards at 10 knots in the Irish Sea after snagging the fishing boat’s nets. The trawler was badly damaged but no one was hurt.
In a similar incident in 1982, another trawler, the Sheralga, was dragged backwards was two miles until it sank around 30 miles off the coast near Dublin. It was later revealed that HMS Porpoise had snagged the Sheralga’s nets while hinting for Soviet submarines in the Irish Sea.