A French fishing trawler had a larger haul than normal, catching the NRP Tridente, a Portuguese Type 214 submarine, in its nets off the coast of Cornwall, England. Despite the Tridente hitting the trawler as it surfaced, no casualties on either vessel were reported in the incident. The sub was in British waters as part of a NATO exercise.
The Type 214, one of two Portugal purchased from Germany, is not the first to have been caught by a trawler. In April, 2015, a similar incident off Northern Ireland involving the British trawler Karen being dragged backwards at 10 knots was initially blamed on a Russian submarine before the Royal Navy accepted responsibility for the incident. The Karen suffered substantial damage to its deck but made it back to port.
A March 2015 incident off the coast of Scotland was blamed on a Russian sub. That time, the sub not only came close to dragging the fishing boat Aquarius down as it tried to free itself from the net, it also made off with the trawler's two-ton catch of haddock and skate, according to The Daily Mail. The Aquarius survived the close call.
The Type 214 sub displaces just over 2,000 tons when submerged. It is armed with eight 21-inch torpedo tubes that can fire IF-21 Black Shark torpedoes or Harpoon anti-ship missiles, and can reach speeds of up to 20 knots. The Type 214 also has air-independent propulsion, which enables it to re-charge its batteries without having to use diesel engines and a snorkel, albeit it does maintain that capability.
Fishing trawlers are not the only vessels that have caught subs. In 1983, the frigate USS McCloy (FF 1038) caught a Soviet Navy Victor III nuclear-powered submarine K-324 with its towed-array sonar. The submarine was disabled, forced to surface, and had to be towed to Cuba for repairs. In 2009, a Chinese submarine also got caught in a towed array cable. The AN/SQR-19 system of USS John S. McCain (DDG 56) snagged the sub's propeller as well. While the submarine was not damaged, the John S. McCain needed to repair its towed array sonar system.
Such incidents have high stakes for the submarines. Most submarines only have a single propeller and shaft, and damage to either can leave the submarine stranded a long way from home. In this case, the Tridente was able to make it back to port.