HMS Trenchant (S91): Three Hundred and Thirty-Five Days at Sea

Constructed at Barrow

HMS Trenchant was built by Vickers Shipbuilding at Barrow-in-Furness, ordered on 22 March 1983, laid down on 28 October 1985 and launched on 3 November 1986, her launch ceremony attended by Vice Admiral Sir Arthur Hezlet, who had commanded the celebrated wartime submarine of the same name. She commissioned into Royal Navy service on 14 January 1989, based at HMNB Devonport.

A Difficult Early Incident

In 1990, during a training exercise, nets from the fishing vessel Antares became snagged on Trenchant, resulting in the trawler's sinking and the tragic loss of four fishermen, a sobering episode that underlined the risks submarines could pose to civilian vessels even without any hostile intent, and one that deserves to be remembered with the seriousness such a loss of life demands.

Records and Firsts

Trenchant ran aground off the coast of Western Australia in 1997 but freed herself with minimal damage, and in 1998 tested non-hull-penetrating optronic mast technology.

In 2007 she became the first Royal Navy vessel to fire the new Block IV Tomahawk cruise missile in a live-firing trial in the Gulf of Mexico, and in 2013 she completed the longest patrol ever carried out by a Royal Navy nuclear submarine, an extraordinary 335 days at sea covering 38,800 nautical miles. She also took part in the Arctic ice exercise ICEX 2018.

The End of Her Service

Following the 2020 Integrated Review, Trenchant left active service in 2021 and was formally decommissioned on 20 May 2022 in a joint ceremony with her sister HMS Talent, in the presence of the Princess Royal, closing out a career defined as much by sheer endurance at sea as by any single dramatic operation.