U-47 carried out ten combat patrols and spent a total of 238 days at sea. She sank 31 enemy ships (totalling 162,769 GRT and 29,150 tons) and damaged eight more. Just after dawn on 5 September, Engelbert Endrass – serving as first watch officer aboard
U-47 – spotted
Bosnia zigzagging and blacked out. Prien surfaced and fired a single shot from his 88 mm deck gun to stop the ship but instead
Bosnia made steam and began radioing an alert ('SSS') along with its name and position. Prien then immediately fired an additional four rounds of which three hit the ship, prompting its crew to abandon ship.
U-47 rendered assistance to the crew of
Bosnia, bringing them aboard the submarine and helping to set up a lifeboat which had capsized during the crew's escape. A Norwegian ship also arrived and took all of the survivors aboard. Following its departure, Prien fired a single torpedo which sank the ship with its load of
sulfur almost immediately. The 2,407 GRT
Bosnia became the second British ship, and first freighter, sunk after
Athenia. Prien refused to radio for assistance on account of the attempt to ram him. He returned to
Gartavon and attempted to finish her as he had his previous victims, but the torpedo malfunctioned and Prien instead used the deck gun to wreck the ship and sink its cargo of iron ore.
Sinking of HMS Royal Oak On 8 October 1939,
U-47 began her second patrol. On 14 October 1939 (six days after leaving port), she succeeded in penetrating the
Royal Navy's primary base at
Scapa Flow. Although most of the
Home Fleet was not at the base at the time,
U-47 spotted the battleship away. After working herself into an attack position, she opened fire with torpedoes. Her first two salvos caused only minor damage to the bow, severing an anchor chain. After reloading the bow tubes, the last salvo of three torpedoes struck the British warship, causing severe flooding. Taking on a list of 15 degrees, her open portholes were submerged, worsening the flooding and increasing the list to 45 degrees;
Royal Oak sank within 15 minutes with the loss of 835 men and boys.
Third to ninth patrol art of
U-47. This image was later used as the emblem for the entire 7th U-boat Flotilla After a lavish celebration in Berlin celebrating the sinking of HMS
Royal Oak in which the crew members of
U-47 were received by
Adolf Hitler and decorated, the boat returned to sea on 16 November 1939. Once the U-boat had left Kiel on 16 November, she headed out into the North Sea. After traveling around the British Isles into the Bay of Biscay and the English Channel,
U-47 sank three more ships:
Navasota on 5 December, the Norwegian
Britta on 6 December, and Dutch on 7 December.
U-47s fifth patrol was the first in which she failed to sink a ship. She left Wilhelmshaven on 3 April 1940, and headed again out into the North Sea. On 19 April, she fired a torpedo at the British battleship with no result. Several destroyers attempted to sink the U-boat with depth charges but
U-47 managed to escape.
U-47s sixth patrol was much more successful. Having left Kiel on 3 June 1940, she ventured out into the North Sea and operated off the southern coast of Ireland. Along with six other U-boats in
Wolfpack Prien, she attacked
Convoy HX 47 and sank the British
Balmoralwood on 14 June. She later sank seven more vessels,
San Fernando on the 21st,
Cathrine on the 24th,
Lenda and
Leticia on the 27th,
Empire Toucan on the 29th,
Georgios Kyriakides on the 30th, and on 2 July. The submarine returned to Kiel on 6 July after 34 days at sea and eight enemy ships sunk.
U-47s seventh patrol consisted of her travelling north of the British Isles and into the North Atlantic, south of Iceland. During a period of 30 days, she sank a total of six enemy ships and damaged another.
U-47s first victory during her seventh patrol was the sinking of the Belgian passenger ship
Ville de Mons on 2 September 1940. This was followed by the sinking of a British ship,
Titan, on 4 September and
Gro,
José de Larrinaga, and
Neptunian on the 7th. On the 9th,
U-47 sank the Greek merchant ship
Possidon, and on 21 September she damaged the British merchant ship
Elmbank. Following these victories, on the 25th,
U-47 entered the French port of
Lorient, which was now under German control following the decisive
Battle of France.
U-47s eighth patrol began on 14 October 1940 when she left her home port of Lorient. While her eighth patrol lasted ten days, she sank four enemy ships and damaged a further two in only two days. On 19 October,
U-47 damaged the British ship
Shirak and sank
Uganda and
Wandby, both of which were British registered. The next day, the U-boat damaged the British ship
Athelmonarch, and sank
La Estancia and
Whitford Point. She returned to port three days later, on 23 October.
U-47 left her home port of Lorient on 3 November 1940 and moved out into the North Atlantic in search of Allied convoys. During her ninth patrol, she damaged three ships,
Gonçalo Velho,
Conch and
Dunsley, and sank
Ville d´Arlon.
U-47 returned to Lorient for the last time on 6 December. On her return Kretschmer presented Adolf Hitler with a lifebelt from
Conch which
U-47 had damaged.
Disappearance U-47 departed Lorient on her tenth and last patrol on 20 February 1941. She went missing on 7 March 1941 and was believed at the time to have been sunk by the British
destroyer west of
Ireland, when a submarine was attacked by
Wolverine and . Postwar assessment showed that the boat attacked there was , which was only damaged. HMS
Wolverine had made an earlier attack on a submarine at 0510 hrs, five minutes after
U-47's last known torpedo attack on the whale
factory ship Terje Viken. Nothing further was heard from
U-47 after this time. To date, there is no official record of what happened to
U-47, although a variety of other possibilities exist, including
mines, a mechanical failure, a victim of her own torpedoes, or possibly a later attack by the
corvettes and .
U-47 had a crew of 45 men during her last North Atlantic patrol in early 1941, all of whom were presumed dead.
Wolfpacks U-47 took part in one
wolfpack, namely:
Prien (12–17 June 1940). ==Summary of raiding history==