Deutsches U-Boot-Museum

• "U-107" and the most successful mission of a Kriegsmarine U-Boat in World War II

On 29th of March 1941 the type IX B U-Boat "U-107" (Built 1939/40 at AG Weser at Bremen, commissioning 08th of October 1940, displacement 1.051 to, submerged 1.178 to, length 76,5 m, width 67 m, speed 18,2 kn, sub-merged 7,3 kn, range 12.000 nm at 10 kn, submerged 64 nm at 4 kn, 4 bow- und 2 rear torpedo tubes, up to 22 torpedoes on board, alternatively up to 44 mines, crew of 56 men) under the command of Kapitänleutnant (= Lieutenant Commander) Günter Hessler departed for its second combat patrol. Together with "U-94" it left its final outfitting berth at Lorient in German occupied France and sailed in convoy until it reached the open Bay of Biscay. The sea areas between the Canary Islands and Sierra Leone in West Africa, respectively Freetown, Liberia was its designated area of operation.

Nothing particular really happened until the 8th of April. The sea was absolutely empty. Suddenly a vessel in darkened mode came in sight. A first single torpedo shot passed under the target uneventful. "U-107" started chasing the vessel, which chose zig-zagging courses at irregular intervals. The second torpedo hit the bow of the British 3.829 BRT vessel "Eskdene". While wildly sending mes-sages for help the vessel kept lying stopped, and started to sink over the bow, however without any indication of really going down.

India position 08.10.1940

After the entire crew of the freighter has gone off board, some 104 rounds of the U-Boats gun eventually caused the "Eskdene" to sink at about 07.47 hrs. Now, Kapitänleutnant Hessler knew that he has sunk a straggler of convoy OG 57. Hence, "U-107" ought to be close to the convoy.

Already late afternoon the widely spread convoy came in sight. A torpedo launched at 19.40 hrs hit the British vessel "Helena Margareta" just under the bridge. Within a minute the 3.316 BRT vessel sank steeply over the bow. The sinking occurred so fast, that 27 sailors of the 36 men strong crew went down. On 09th of April, shortly after midnight, "U-107" established contact again to the convoy and reached soon a favorable position for another attack. At 00.37 hrs Hessler launched a two-salvo torpedo attack on the British vessel "Harpathian". While the first torpedo missed, the second hit the 4.671 BRT vessel after 56 seconds running time.

The vessel, which was to transport aircraft parts for the Royal Air Force to West Africa, broke in the middle and sank within few mi-nutes. Four sailors out of the 43 men strong crew did not survive. In the afternoon of that day another big vessel came in sight, which soon was identified as tanker. At 19.20 hrs a two salvo torpedo launch was executed from the rear torpedo tube No V and VI. The first "eel" hit the tanker just before the bridge, the second detona-ted some 15 meters behind the bridge. The vessel managed to sail on despite the torpedo impacts, but it was chased further by "U-107". Only after four more torpedo hits the tanker sank in the mor-ning of the 10th of April. It soon was clear, that it has been the British 8.512 BRT tanker "Duffield", which was underway from Curacao to Gibraltar with some 11.700 tons of oil. The "Duffield" fell as the last victim of convoy OG 57 to "U-107". 25 sailors of the 52 strong crew died.

On 21st of April 1941 a huge vessel was made out at calm seas. "U-107" resumed attack position and launched a two salvo torpedo attack at 14.20 hrs. The first torpedo hit right behind the funnel after a mere 35 seconds of running time, causing an immediate explosion of the boiler.

The second torpedo detonated after 38 seconds in the fully loaded mid section of the vessel. It was the British 10.305 BRT freighter "Calchas", and it eventually sank at 14.58 hrs following a "Coup de grace"-torpedo launch. When "U-107" surfaced again, the watch keepers at the conning towers counted four life boats with about 100 survivors. As a matter of fact, a total of 104 crew members and 9 passengers have been on board the freighter, 31 sailors and 1 passenger did not survive the sinking.

In the evening of the 30th of April "U-107" sighted the British 7.417 BRT motor vessel "Lassell" and sank it on 21.58 hrs. On 03rd of May "U-107" met the German Naval Oiler "Nordmark" and executed immediately oil replenishment. Thereafter, the boat returned to its assigned area of operations, where on 09th of May it met the German supply ship "Egerland" , to take over torpedoes, food supplies and fresh water. Later on, "U-107" headed for sea areas off Freetown in its area of operations.

Shortly after midnight of the 17th of May the Dutch 8.029 BRT oiler "Marisa" ran into "U-107". At 00.36 hrs a torpedo from tube II brought the oiler to a stop, which immediately started to sag deeper and to bend at the mast section of the ship.

After another torpedo at 01.15 hrs the vessel was sunk by means of gun fire. The following day at 22.27 hrs the British 8.286 BRT vessel "Piako" was torpedoed by "U-107" about 120 nm off Freetown and, after the crew had left the vessel, was sunk by a "Coup de grace"-torpedo at 22.43 hrs. Finally, on 27th of May at 01.01 hrs, the British 5.108 BRT vessel "Colonial" was torpedoed in the sea areas off Freetown and sunk at 01.46 hrs with another "Coup de grace"-torpedo.

The "Colonial" was a vessel of the already dispersed convoy OB 318. The next day, the Greek 3.748 BRT vessel "Papalemos" was hit. The vessel was enroute from Freetown to the United Kingdom and was brought to a stop by "U-107" through a torpedo hit, but eventually sunk by gun fire. 2 men from the 29 strong crew did not survive. On 31st of May "U-107" encountered the British 5.664 BRT vessel "Sire" sailing with ballast only and torpedoed it at 07.39 hrs. Three minutes later "Sire" was sent to the ground by another "Coup de grace"-torpedo.

Already next day, "U-107" detected the British 5.013 BRT vessel "Alfred Jones". Hessler launched a two salvo torpedo attack against the vessel, both torpedoes detonated at the rear part of the ship, which was immediately covered by a huge cloud of smoke. Slowly the vessel listed towards its starboard side, while "U-107" passed behind its stern. When debris of the vessel hit the periscope, Hessler retracted it for some time. After he raised the periscope again the U-Boat captain observed life boats being lowered to wa-ter at the vessels inclined port side and the crew in parts clim-bing down to the boats via a rope-ladder. Hessler remained suspicious, as many people on board appeared to be somewhat strange, many of those even in immaculate white uniforms.

Therefore, he observed the modern frei-ghter a bit more precise through the air aiming periscope. Immediately, he could spot everywhere people on the vessel, which did hide behind all possible covers and boxes. Consequently, Hessler decided for another "Coup de grace"-torpedo again-st the vessel stopped. After the detonation of the torpedo the sailor still on board jum-ped off board, because the "Alfred Jones" started to sink fast over its stern.

The men swimming in the water were taken on board by the life boats already afloat. Hessler was wondering about the high num-ber of crew on board the vessel, he estima-ted it to be some 150. Because he assumed guns and depth charge dropping units under camouflage behind those large boxes at the vessels upper deck he classified the vessel to be a raider or a U-Boat trap. However, Hessler was wrong, the "Alfred Jones" was nothing of that kind, she was the vessel of the convoy commodore of convoy OB 320, who had embarked on this vessel together with his entire staff.

Hence, the many smart uniforms! The "Alfred Jones" was enroute to Freetown with a cargo of about 2.000 tons of military goods, in particular aircraft parts, which explained the tall boxes on the upper deck.

Hessler also got the number of crew wrong, there were no 150, but a mere 63 on the freighter, two of those died at the first attack by "U-107. On 08th of June 1941, just 82 nm off Freetown, the British 7.816 BRT motor vessel "Adda" was sunk by one torpedo. 8 men from the 154 strong crew did not survive. In addition, there were 260 passengers on board the "Adda", two of those died.

When the air surveillance became more dense, "U.107" withdrew from the sea areas off Freetown. Nevertheless, on 13th of June some 500 nm northeast of Freetown, "U-107" managed to sink the Greek 4.981 BRT vessel "Pandias" by means of one torpedo. The freighter bound for Table Bay carried a load of 4.894 tons of coal and 1.050 ton of military goods, plus 11 "Spitfire" fighter aircraft. After the sinking of the "Pandias" "U-107" surfaced and closed in to the life boat. Hessler helped the Greek master by providing him with navigational information, also he gave to the shipwrecked crew cigarettes, fresh water and rum. Sadly, 11 sailors from the 34 strong crew in the life boat did not survive the long and enduring journey of more than 500 nm to the African coast.

On 19th of June "U-107" started its return leg to Western France, where the boat berthed on 02nd of July 1941 at Lorient. With that, the most successful combat patrol by a German U-Boat in World War II was over.

During this second combat patrol after its commissioning "U-107" achieved sinking of 14 vessels with a total tonnage of 86.699 BRT. Already during his first combat patrol, Hessler had sunk 4 merchant vessels with a total tonnage of 18.482 BRT, giving him after his return a total success of 105.181 BRT being sunk. For that, Kapitän-leutnant Günter Hessler was awarded the Knights Cross to the Iron Cross on 24th of June 1941.

Source: Picture: Deutsches U-Boot-Museum Text: H.J. Röll, unofficial translation by Peter Monte