The second torpedo exploded after a run of 4 minutes 7 seconds. This shot had obviously failed — a dud, or a miss, perhaps due to the steamship changing course after the first detonation was heard.

Jenisch tried to chase the steamer, but had to take avoiding action to prevent his U-boat ramming into the ship as it turned to run west towards the coast at a speed of at least 12.5 knots — U-22's maximum speed. Cyprian Prince was actually doing 13 knots, and U-22 was unable to catch the ship, and had no opportunity to fire any further torpedoes at it.

It would seem that the torpedo fired at the Cyprian Prince may not have missed. The banging noise that wakened Chief Engineer Montgomery might possibly have been the torpedo hitting several times against the side of the vessel as it passed at an angle without the contact pistol firing. After the torpedo cleared the ship's side it would continue to the end of its run before sinking. German torpedoes were fitted with two pistols, one contact and one magnetic, one of which the U-boat commander selected before firing. It was found that the magnetic pistol was too sensitive and the contact pistol would only work against a straight surface. Against a curved surface, the torpedo could glance off without exploding.

The Admiralty claimed the first news of the sinking of the Exmouth was when Cyprian Prince reached Kirkwall at 13.00hrs. This was despite the fact that Captain Wilson had attempted to send a visual signal by Aldis lamp to Noss Head, Duncansby Head and Muckle Skerry, as he passed each in turn, but had been unable to elicit any response. We also know from U-22's Ktb that they heard either the destroyer or the steamship sending at a very rapid speed “SOS. Sinking in lat 58°18'N, long 02°25'W”, and Wick Radio (GKR) on the 600 metre waveband repeating “SOS unknown vessel sinking in position 5818N, 0225W”. The war diary of the Admiral Commanding Orkney and Shetland (ACOS), contains an entry for 21 January: “Cyprian Prince broadcast SOS at 0400 (sic) and made report on arrival at Kirkwall”.

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