Patrol 10 - 20.02.1941-07.03.1941
20.02.1941 U-47 departs dock at Lorient. The departure of this mission is delayed by a few days because the trial run had revealed some minor faults. Von Varendorff, who had received his promotion after the previous mission, has left the boat. He is in Germany attending a Commanding Officers' course. Korvettenkapitän von Schnurbein is also on board U-47 for this patrol as a "confirmation candidate" before being given his own command. The normal complement of a VII at this time is 44. The addition of Von Schnurbein makes a crew of 45 on this patrol.
26.02.1941 Steam freighter Kasongo (Belgium, 5,254 grt), part of convoy OB-280, attacked by torpedo, sunk. Time of first attack, not cited; first hit registered 0018 hours. Location 55°50N/14°20W. Following Prien's reporting the presence of Convoy OB-280, Dönitz ordered reinforcements. However when it appeared that they wouldn't make it in time, Prien took on the convoy alone. He was to sink four vessels himself, and then act as a beacon in order to guide a squadron of Condor bombers to the inviting target, which resulted in seven futher vessels being sunk.
26.02.1941 Motor tanker Diala (United Kingdom, 8,106 grt), part of convoy OB-280, attacked by torpedo, damaged. Time of first attack not cited; first hit registered 0025 hours. Location 55°50N/14°00W. The Diala managed to make it back home after its skirmish with U-47, but almost a year later on 14 January 1942 it was attacked and hit by the Type VIIC U-553 under the command of Kapitänleutnant Karl Thurmann. The motor tanker suffered catastrophic losses during the attack, and was eventually left to its fate by the remaining crew.
26.02.1941 Motor freighter M/S Rydboholm (Sweden, 3,197 grt), part of convoy OB-280, attacked by torpedo, sunk. Time of first attack not cited; first hit registered 0110 hours. Location 55°32N/14°24W. Whether U-47 attacked the Rydboholm or not has been debated; Jürgen Rohwer has argued however that no other U-boat on patrol at that time could have attacked in the given position (J. Rohwer, Axis Submarine Successes of World War Two, p. 44 f. 4) What is clear is that the ship was still afloat for a period after U-47's attack - a further debate has ensued as to whether it sunk of its own accord or was finished off by German aircraft the following day.
26.02.1941 Motor freighter Borglund (Norway, 3,636 grt), part of convoy OB-280, attacked by torpedo, sunk. Time of first attack not cited; first hit registered 0137 hours. Location 55°50N/14°00W. During the attack on convoy OB-280, independent research from a number of sources have cited two further ships attacked by U-47 between midnight and 0200 hours on 26.02.1941: these were the Motor freighter M/S Samuel Bakke (Norway, 4,719 grt), damaged by U-47 at location 55°36N/13°42W, and the steam freighter D/S Solferino (Norway, 2,580grt), which was attacked (but presumably not hit) by U-47. Both vessels were subsequently sunk following an aerial attack the same day.
28.02.1941 Steam freighter Holmelea (United Kingdom, 4,223 grt), part of dispersed convoy OB-280, attacked by deck gunfire, sunk. Time of first attack not cited; first hit registered 0126 hours. Location 54°24N/15°45W. Prien later receives the news that he has been promoted to Korvettenkapitän.
07.03.1941 Whaler Terje Viken (United Kingdom, 20,638 grt), part of convoy OB-293, attacked by torpedo, damaged. Time of first attack not cited; first hit registered 0505 hours. Location 60°00N/12°50W. Terje Viken was struck again and incapacitated by a torpedo from Kretschmer's U-99; it was subsequently sunk by British craft a week later, 14.10. The attack on the Terje Viken was also the last noted action of U-47.
07.03.1941 U-47 reported missing to BdU, in the region around Rockall Banks in the North Atlantic west of Ireland, approximate location 60°00N/19°00W south of Iceland. As with a number of aces, the loss of U-47 has been a subject of major debate. It is widely believed that the U-boat was sunk during 07/08.03.1941 following a depth-charge attack by the British destroyer HMS Wolverine, but other sources have postulated that U-47 was hit by one of its own torpedoes that had gone offline. Two British corvettes, HMS Camellia and HMS Arbutus have also been mentioned as possible claimants. Korvettenkapitän Prien, and all of his 44 crew, were lost to the sea.
Total days at sea: 17
Enemy vessels sunk: 4
Total tonnage: 16,310 grt
The Final Analysis
Total number of Sorties: 12
Total number of Patrol Missions: 10
Total number of Sea days: 238
Total number of enemy vessels sunk: 30
Total tonnage of sunk enemy vessels: 193,808 tons (30 merchant vessels, 164,953 tons)
Total number of enemy vessels damaged: 8
Total tonnage of damaged enemy vessels: 63,282 tons