Final voyage and sinking
On 8 October 1942[2] Abosso left Cape Town, South Africa for Liverpool carrying 210 passengers: 149 military and 61 civilians, including 44 internees, among them the German-born and Jewish author Ulrich Alexander Boschwitz, 10 women with children and two or three British distressed seamen[5] (the official term for abandoned seamen away from home without a ship for various reasons). Her DEMS gunners were 13 from the Royal Artillery Maritime Regiment and seven from the Royal Navy.[5] She was also carrying 400 bags of mail in her mail room and 3,000 tons of wool in her holds.[2]
Her military passengers included 50 or 51 Dutch conscripts, 44 newly trained pilots fresh from No 23 Service Flying Training School, X Flight, Advanced Training Squadron, at Heany, Bulawayo, Southern Rhodesia[1] (40 for the RAF and four for the Fleet Air Arm), and 33 or 34 Dutch submariners being transferred to a new submarine.[5] The submariners were from three Royal Netherlands Navy submarines: HNLMS K IX and HNLMS K XII, both of which had been transferred to the Royal Australian Navy; and HNLMS K X, which had been scuttled in the Dutch East Indies to prevent her capture by invading Japanese forces. They were travelling to take over a U-class submarine that Vickers-Armstrongs was building at Barrow-in-Furness and was intended to be launched as HNLMS Haai.
Abosso sailed alone and unescorted, despite having a top speed of only 14.5 kn. A commander of the Dutch submariners, Luitenant ter zee der 1e klasse Henry Coumou, objected beforehand that this was an unreasonable risk to take, but British authorities overruled him.
At 22:13 on Thursday 29 October 1942 Abosso was in the Atlantic about 589 nmi north of the Azores[1] when GS U-575, commanded by Kapitänleutnant Günther Heydemann, fired a spread of four torpedoes at her. One hit Abosso's port side abaft her bridge. The ship's engines stopped, all her lights failed, and she started to list heavily to port.[2] Heydemann survived the war and became a successful businessman in Germany.
Abosso had 12 lifeboats. The even-numbered boats were on her port side and it is not clear whether any of them was launched. The odd-numbered boats were on her starboard side. As No. 3 boat was being lowered, one of its falls was let go and all of the boat's occupants were thrown into the water. No. 3 boat seems to have been carrying most of the Dutch submariners. No. 5 boat was launched successfully and managed to rescue four of the Dutch from the water.[2] No. 9 boat was also launched successfully. It was a motor boat and moved around picking up survivors from the water.
As Abosso settled in the water, she temporarily righted herself, her crew got her emergency generator working, and her floodlights were switched on to help the evacuation. Almost immediately after this, U-575 fired a torpedo from one of her stern torpedo tubes, which hit Abosso at 22:28 (Berlin time) forward of her bridge. At 2305 hrs (Berlin time) Abosso sank bow first. The submarine then surfaced, approached the débris area, and scanned the boats with her searchlights. Kptlt. Heydemann reported about 10 lifeboats and 15 to 20 liferafts afloat and occupied. Heydemann did not try to question survivors to identify the ship, and claimed in his report that this was because the weather was poor.[2]
