Collision between pelagic trawler Antares and trafalgar-class submarine HMS Trenchant with loss of 4 lives

Location: Off the Isle of Arran, Scotland.

Accident Investigation Report: Antares and HMS Trenchant

Read our marine accident investigation report, which includes what happened, actions taken, and recommendations:



On 22 November 1990 at 0217 hrs Trenchant had a close sonar contact to starboard and turned to port to avoid it. Banging noises were then heard in the submarine and it was assumed by those in the control room that a fishing trawl had been snagged. On regaining periscope depth, two fishing vessels were seen, apparently engaged in normal fishing. Trenchant surfaced at about 0300 hrs and a trawl wire was discovered fouled on the submarine casing. Attempts by the submarine to contact the two fishing vessels by radio were unsuccessful. Since everything on the surface appeared normal, Trenchant reported the incident to Faslane base and continued with her exercises.

Safety Issues

The main findings of the investigation are that the accident was caused by a partial breakdown in both the structure and the standards of watchkeeping on board Trenchant, following the completion of a command course exercise. Also the stowage position and securing arrangements of the inflatable liferaft on Antares were deficient, such that it failed to float free and inflate when the vessel sank.


Based on the Inquiry into the accident and the findings of the inspectors, a number of recommendations are made which, if implemented, will prevent recurrence of such an accident.

Ths report was published on 9 July 1992.

Published 23 January 2015