Her passage from Malta to Gibraltar took her on a route hugging the Sicilian south coast and she was to carry out a short patrol off Cavoli Island (Sardinia). The report of her loss by Captain S.1 (Flotilla leader) can be found in the National Archives. There is no mention at all that she would have gone near Tunisian waters and she communicated by SST (sonar communications) with HMS P34 in 37�28.5' N, 12�35.5' E (her last known position) on 27 October 1941 which confirms that the route she was following was strictly according to plan. The hypothesis that a submarine would divert from her route at the whim of her captain is quite frivolous. She was instructed by Gibraltar to specify if she was unable to comply. Any diversion caused by unforeseen events could not be made without informing Malta or Gibraltar to minimise the risk of being attacked by their own aircraft or A/S craft. Tetrarch did nothing of the sort. She was probably mined off the western tip of Sicily, several minefields were laid there by the Italians during the summer of 1941. In any case, what would have been the purpose of exploring the Bay of Tabarka which was only used by fishing vessels and was in Vichy-occupied Tunisia? No minefield was laid there by French or Axis forces until the second half of April 1943 (during the last days of the Axis occupation of Tunisia). At that time German MTBS laid mines to prevent Allied MTBs from Bone raiding Axis traffic between Sicily and Bizerta. Her wreck has still to be found. Ref. ADM199/1115, ADM199/2232-2233 (TNA) Read more at wrecksite: https://www.wrecksite.eu/wreck.aspx?16100