In a heavy sea and bad weather the Ark Royal was ranging a striking force. At 1315/26 the Sheffield was detached to the southward with orders to close and shadow the enemy, who was then estimated to be 40 miles south-west of the Renown. The visual signal54 ordering this movement was not repeated to Ark Royal, an omission which had serious consequences (F.O. Force H despatch paragraph 21) for the aircraft, did not know that the Sheffield had parted company. The interrogation of observers had caused some doubt in the Ark Royal whether the ship reported was a battleship or cruiser. Torpedoes with Duplex pistols were therefore adjusted for 30 ft. The striking force of 1455 Swordfish were off at 1450/26 and making South. Weather and cloud conditions were particularly bad and reliance was placed in an A.S.V. set which located a ship some 20 miles from the estimated position of the enemy, that had been given to the leader on taking off. At 1550 they attacked through the cloud and fired eleven torpedoes. Unfortunately the supposed enemy was the Sheffield. Fortunately she was not damaged. Two torpedoes exploded on hitting the water and three exploded harmlessly astern. In the Sheffield there was an immediate appreciation of the mistake; she increased at once to full speed and did not open fire. The Bismarck was some 15 miles to the southward.56 The striking force returned and were all landed on by 1720/26. About half an hour later, at 1740/26, the Sheffield sighted the Bismarck (in about 48° 30’ N., 17° 20’ W.) and, reporting her position, took station ten miles astern and began to shadow her closely for four fateful hours. The first relief shadowers from the Ark Royal were up and reported definitely that the ship was the Bismarck.
54. The report to Admiralty at 1345 that Sheffield had been detached had been received in Ark Royal but had not been decoded, when striking force left; Ark Royal made a warning signal to aircraft at 1620/26.
55. Fifteen flew off, one returned immediately.
56. A Catalina reported her at 1500/26 in 47° 30’ N. 19° W. which, would, make her some 82 miles south pf the Sheffield. The same Catalina, (M.240) was in visual touch with the Sheffield at 1740/26, and gave its own position at 1800/26 as 47° 15’N. 18° 23’ W. some 62 miles south of the Sheffield’s (see Plan 6).