In September 1941, hthe merchant ship Empire Guillemot was sent with supplies for Malta. She had an odd cargo, as she carried "fodder for livestock". The passed through the Western Mediterranean by flying "false colours". At various times, she flew the flags of Spain, France, and Italy. She was seen by aircraft, but not disturbed. She arrived at Malta on 19 September.
Submarines were also used to carry supplies to Malta, although only small quantities could be sent this way. The minelaying submarines Cachelot and Rorqual had larger volumes, so they were especially suitable. The larger O-class ships, such as Osiris and Otus also were used. On 30 July 1941, the Chachelot was caught on the surface by an Italian torpedo boat and had to be eventually scuttled. This is based on the account in Vol.II of the Official History.