Empire Endurance was a steam cargo liner that was built in 1928 as Alster by Deschimag Werk Vulkan, Hamburg, Germany for the shipping company Norddeutscher Lloyd. In the years leading up to the Second World War Alster carried cargo and passengers between Germany and Australia. After the outbreak of war she was requisitioned by the Kriegsmarine for use as a supply ship.

Alster was captured off Norway on 10 April 1940 by the British destroyer . Initially serving under the original name as a repair, supply and cargo ship in Norway, she was later passed to the Ministry of War Transport (MoWT) and renamed Empire Endurance. She served until 20 April 1941 when she was torpedoed and sunk by the German submarine south-east of the islet of Rockall in the North Atlantic Ocean.

Description The ship was a cargo liner. Deschimag Werk Vulkan built her in Hamburg as Alster,Kludas 1998, p. 64 with yard number 211.

Alster was long, with a beam of . She had a depth of . She was assessed at , , 12,000 DWT. She had four masts, a single funnel, a round stern and a slanted stem.Schwadtke 1974, p. 137

The ship had a single screw driven by both a triple-expansion steam engine and a steam turbine, both built by Deschimag, and coupled by Deschimag's patented Bauer-Wach system. The triple-expansion engine had cylinders of , and diameter by stroke. Steam exhausted from its low-pressure cylinder passed through a diverter valve to a steam turbine. Via double-reduction gearing and a Föttinger fluid coupling the turbine drove the same shaft as the piston engine. Together the two engines developed a total of 6,500 indicated horsepower, which gave her a top speed of .Schwadtke 1974, p. 68-69

History Alster was launched on 5 January 1928, and completed on 25 February 1928. She was built for Norddeutscher Lloyd. She was given the code letters QMHG and registered in Bremen. She served on routes between Germany and Australia and East Asia. Lloyds Register entries show that she held a passenger certificate from 1934 to 1940. With the change in code letters in 1934, Alster was given the call sign DOEO. She had a crew of 69 and could initially take 14 passengers. In 1930 the passenger capacity was increased to 16.

Norwegian Campaign and capture On 18 March 1940 the Kriegsmarine requisitioned Alster. She was used as a supply ship in Operation Weserübung – the German invasion of Norway, forming part of the invasion's , transporting heavy equipment. Alster departed Brunsbüttel at 02:00 on 3 April, destined for the North Norwegian port of Narvik. She was one of four supply ships sailing from the Schleswig-Holstein port in support of German forces landing at Narvik on 9 April, under cover of sailing to Murmansk in the Soviet Union.Sandvik 1965 vol. 1, p. 135 None of these ships made it to their destination. The lack of supplies and artillery would leave the German forces fighting at Narvik vulnerable. Upon reaching Norwegian waters, Alster and the tanker Kattegat, also bound for Narvik, were escorted by the Norwegian torpedo boat HNoMS Trygg as far as Kopervik, where they arrived on 5 April. At Kopervik the German plans suffered a delay because of a lack of pilots to guide the ships northwards, Alster continuing later that day, while Kattegat departed Kopervik only on 6 April. Many of the other supply ships sent out in advance of the invasion also suffered delays, putting the supply part of the invasion plans out of schedule.Steen 1958, p. 43 While at Kopervik, Alster and Kattegat were inspected by the torpedo boat , the Norwegians finding nothing irregular. By 8 April, Alster had reached Vestfjorden, where she was hailed by the Norwegian patrol boat , which warned her of the British naval minefield laid in the area earlier that day. Alster steamed to Bodø, to await developments. Two days later, on 10 April, following the outbreak of war between Norway and Germany the previous day, Syrian was despatched by Norwegian authorities to seize Alster off Bodø. When Syrian found Alster, the commander of the small Norwegian patrol boat chose not to board the German vessel as he suspected she was armed and possibly carrying troops. As Alster attempted to escape, Syrian sent out messages to the British warships in the area.Berg and Vollan 1999, pp. 66–67Haarr 2009, pp. 66, 333Pedersen 2009, p. 224Steen 1958, p. 170

On 10 April, Alster was captured by the British destroyer in Vestfjorden, north of Bodø. When intercepted the German crew made an unsuccessful attempt at scuttling the vessel, setting off one explosive charge. The light cruiser had also been sent after Alster, but had run aground near Bodø and suffered serious damage.Derry 1952, pp. 46-47 With the British capture of Alster, no more German supply ships were heading for Narvik and the forces there,Lunde 2009, p. 253 leaving General Eduard Dietl's troops with the supplies on board the tanker Jan Wellem and the large stockpiles of weapons, ammunition, uniforms and food captured at the Norwegian Army base Elvegårdsmoen.Sandvik 1965 vol. 1, pp. 214–15 At the time of her capture, Alster was under the command of Kapitän Oskar Scharf, who had previously commanded the Blue Riband-holding ocean liner .

Initially Alster was brought to the improvised British naval base at Skjelfjord in Lofoten. On arrival at Skjelfjord on 11 April, a prize crew from Penelope took over responsibility for the ship. At Skjelfjord, the captured German crew made an unsuccessful attempt at scuttling Alster by opening the ship's sea valves. While at Skjelfjord Alster, being equipped with derricks, was used to help repair damaged Allied warships. One of the vessels on which emergency repairs were carried out from Alster, was the destroyer , which had lost her bow during the naval battles off Narvik.Haarr 2009, pp. 353, 370Haarr 2010, p. 212 Alster was also used as an accommodation ship for the crews of the damaged vessels at Skjelfjord.Haarr 2010, p. 216 On 24 April Alster departed Skjelfjord for the Northern Norwegian port of Tromsø, manned by a British prize crew.Haarr 2010, p. 217Steen 1958, p. 171 The eight German officers captured on Alster were transferred to the United Kingdom on the British destroyers and .Haarr 2010, p. 433 In all, 80 Germans were captured on board Alster, and all were eventually sent to the United Kingdom.

Her cargo of 88 lorries, anti-aircraft guns, spare parts for aircraft, ammunition, communications equipment, coke and 400–500 tons of hay, was unloaded in Tromsø on 27 April, as part of the Allied support of the Norwegian forces fighting the German invasion of their country. The cargo was put to use in the supply and defence of the Tromsø area, except for the hay, which was quarantined by the Norwegian authorities at Ringvassøy for fear of foot-and-mouth disease.Christensen and Pedersen 1995, pp. 413–15Haarr 2010, p. 265Sandvik 1965 vol. 1, p. 202Sandvik 1965 vol. 2, pp. 161–62 The coke on board Alster had been placed by the Germans in a layer covering the deck.Walker 1989, p. 18 The supplies on Alster were transferred to the Norwegians by the Allied naval commander Lord Cork after the Norwegian authorities had made repeated request for weapons and other war matériel, and was intended to be a first effort before the arrival of larger quantities of arms and ammunition promised to the Norwegians.

The lorries and weapons from Alster were received, assessed and distributed by Norwegian military personnel under the command of Major Karl Arnulf, who had arrived in Tromsø on 7 May 1940, having made his way from German-occupied South Norway. The communications equipment included both a mobile radio transmitter, which was used as a spare for Tromsø radio broadcasting station, as well as large quantities of field telephone equipment which was sent to the units of the Norwegian 6th Division on the Narvik front. The field equipment from Alster replaced the old and worn field telephone systems in use up to that point. Training on the German equipment was provided by Swedish volunteers.Sandvik 1965 vol. 2, p. 183 In order to satisfy British naval regulations with regards to prize cargoes, the British consul in Tromsø observed the unloading of Alster, and wrote an affidavit listing what had been given to the Norwegians, which was sent to the Admiralty.Grehan and Mace 2015, p. 60 While docked in Tromsø in May 1940, Alster had 70 captive Germans on board. At Tromsø, Alster was manned by Norwegian sailors, replacing the British prize crew.

On 16 May a request was made to the Admiralty for a call sign for Alster, the ship departing Tromsø the next day for Kirkenes in Finnmark, escorted by the anti-submarine whaler . She was despatched to the northern port to retrieve a cargo of iron ore. Arriving on 19 May 1940, Alster loaded some 10,000 tons of iron ore over four days, sailing south to the port of Harstad on 22 May, still escorted by HMS Ullswater, as well as the Norwegian patrol boat . On 23 May, the British submarine HMS Truant made an unsuccessful attack with two torpedoes on Alster off Havøya, despite efforts having been made to both keep the cargo ship away from the submarine's patrol area, and to warn Truant of the ship's identity. The torpedoes missed, exploding when they hit land. Alster and HMS Ullswater arrived at Harstad on 26 May, with the escort vessel sailing northwards to Hammerfest with mail and provisions for the heavy cruiser .Haarr 2010, p. 263Steen 1958, p. 251 While Alster was at Harstad shipping in the town's harbour was repeatedly subjected to attacks by Luftwaffe Heinkel He 111 bombers, the ships being defended by Gloster Gladiator fighters of the No. 263 Squadron RAF operating from Bardufoss Air Station and anti-aircraft artillery. During one of the attacks on 26 May the ship's Norwegian fireman was mortally wounded by bomb fragments, dying in Harstad Hospital later the same day.Ingebrigtsen 1995, pp. 182–183Ording 1950, p. 794Hafsten 1991, p. 95–96

On 27 May Alster sailed for the United Kingdom in a five-ship convoy which included the crippled HMS Eskimo. In addition to her cargo of iron ore, the ship carried 209 British military personnel, 46 Norwegian military personnel and 72 German prisoners of war. She also transported the "B" gun turret from Eskimo, which had been removed from the destroyer during makeshift repairs. Alster arrived at Scapa Flow on 31 May, unloading her passengers there. Sailing on 3 June, in the company of the passenger steamer and escorted by the destroyers and , she arrived at Rosyth in Scotland on 4 June 1940.Haarr 2010, p. 436

As Empire Endurance

Alster was passed to the MoWT and renamed Empire Endurance. She was given the UK official number 164841 and call sign GMJJ. She was registered in Middlesbrough. She was placed under the management of Alfred Booth and Company. Empire Endurance sailed in Convoy FN 255, which left Southend, Essex on 17 August and arrived at Methil, Fife two days later. She then joined Convoy OA 202, which left on 21 August and dispersed at sea on 25 August. Her destination was Montreal, Quebec, Canada, where she arrived on 3 September. Empire Endurance sailed on 12 September for Sydney, Cape Breton, Nova Scotia, arriving three days later. She then joined Convoy HX 74, which departed from Halifax, Nova Scotia on 17 September and arrived at Liverpool, Lancashire, United Kingdom on 2 October. She was carrying general cargo stated to be bound for Newcastle-upon-Tyne, Northumberland. She left the convoy at the Clyde on 2 October.