24.5 [24 May 1941]
In the early morning hours enemy units made contact with the battle group Bismarck and Prinz Eugen, which was breaking out through the Denmark Straits. There was an engagement with enemy battleships during which Hood was sunk. Western Group boats were informed of this and that further enemy operations were likely.
It was considered whether anything could be done at once with these boats to give support to the Bismarck group, but it was decided to wait until C. in C. Fleet's [Admiral Gunther Lutjens] intentions were known. I telephoned C. in C. West [Admiral Alfred Saalwachter] and placed all the U-boats at his disposal regardless of the war against merchant shipping and he confirmed my view. He would make his requirements known as soon as he heard from C. in C. Fleet.
As operations proceeded, C. in C. Fleet requested that Western Group U-boats be concentrated together in square AJ 68, he intended to lure the enemy units which were still shadowing him into the U-boats' position A.M. on the 25th. At 1613 an order was given for U 94, 43, 46, 557 and 66 to form a patrol line to run N.W. to S.E. through the square. U 93 and 73, which were further away, were to take up positions N.E. of this patrol line. In preparation for the event of the Fleet's returning, U 48, 97, 98, on passage in Biscay, were ordered to attack areas in BE 6420 to 6620, at the request of Group Command West [headquartered in Paris]. U 138 was to have occupied position adjoining those to the East, but could not carry out her orders owing to lack of lubricating oil.
U 556 (on her return passage without torpedoes) was ordered to join this group. She could at least be useful as "look out."
U 73, on outward passage, which should have been about half way between Western and Biscay groups, was ordered to make her position, after which she was to be allocated to one or other group.
U 108 and 552 were also to leave Lorient and St. Nazaire respectively P.M. and on the 25th to join the Biscay group. The [7th] Flotilla S[enior].O[fficer].[Lieutenant Commander Sohler] had, of his own accord, given orders for U 552 to be ready to sail.
All available forces had then been mobilized. By evening it was known that the Fleet's intentions were changed: the 2 ships were to separate, Prinz Eugen to move away to the S.W. and Bismarck probably to enter St. Nazaire. Boats concentrated in AJ 68 were then dispersed and, on Group Command's instructions, ordered to form a patrol line from AJ 6115 to AK 7215.
25.5. (Night) [25 May 1941]
When news was received that Bismarck had been torpedoed by an enemy carrier-borne aircraft it seemed more than ever likely that she would put into St. Nazaire. The question of screening the inward-bound battleships came into the foreground.
The disposition in Western Biscay was reinforced by U 73, which was nearer to this group than the Western Group, and U 74. Although she had been badly hit by depth-charges and was on her way back, U 74, realizing the seriousness of the situation, had reported of her own accord that she could reach a position near the Biscay Group by next morning.
This meant that at least 6 boats were disposed along Bismarck's inward route, although 2 of them (U 556 and 98) had no torpedoes and one (U 74) was badly damaged.
The Western boats in patrol line were ordered to proceed E. at cruising speed to intercept the enemy units (aircraft carriers) which were following the battleship. Contact with our own ships was lost at 0213 and apparently not regained.
At the request of Group Command West the boats in Biscay were given the following order:
"U 73, 556, 97, 98, 48 to form a patrol line from BE 6155 to BF 7155, depth 20 miles. U 74 to make for BE 5350 as attack area."
As soon as it could be assumed that our own units were sufficiently far South, the Western Group was ordered to resume their original positions in patrol line. U 147 left Bergen and was allocated the area N. of England to West of the North Channel.
26.5 [26 May 1941]
U 103 reported 11 ships totaling 56,245 GRT sunk so far. Bismarck's return passage proceeded according to plan. She was unobserved until 1050, then picked up by an enemy aircraft and shadowed. Surface forces then came up. She reported her position at 1844 in BE 53, course 115 degrees, 24 knots. She was being shadowed by a Sheffield class cruiser. The situation was now clear, the enemy was to be expected from the N.W. Bismarck passed E. of the U-boat line. U 48, who was then not expected to encounter the enemy in the South, was ordered North by radio.
U 556 reported T.O.O. [Time of Origin] 2010: BE 5332 King George, Ark Royal, air activity. She lost visual contact with the enemy at 2035 and at 2240 also her hydrophone contact which had been maintained until then. Towards 2130 information was received from Group Command West that Bismarck had been hit by 2 more torpedoes and was no longer maneuverable. Her position was BE 6192. All boats in Biscay which still had torpedoes, i.e. U 74, 48, 73, 97, were ordered at 2141 to make for this position at maximum speed. Task: protection of Bismarck. No further reports were received from or of Bismarck and at 2319 the boats without torpedoes, U 556 and 98, were also sent to BE 6277, so as to make contact with the battleship, to bring up the torpedo carriers and provide better cover for this area, which must now be the main scene of events. After consultation with Group Command West, square BE 6279 was, on the basis of all available information (including a number of radio intelligence reports from enemy shadowers) taken as Bismarck's most likely position. The U-boats' operations were greatly hampered by the heavy weather (wind 7 - 9). Use of armament was hardly possible. U 98 could not carry out her orders owing to lack of fuel. She was ordered to remain in her position for as long as possible.
U 111 reported supply completed. She returned to the Western boats' patrol line.
27.5 [27 May 1941]
0015 U 73 [commanded by Lieutenant Helmut Rosenbaum] sighted Bismarck and enemy forces in BE 6155. At 0042 the U-boats were ordered to search the area BE 6277 to BE 6192. Bismarck was to make beacon-signals to assist them.
U 73 reported at 0231: "Last observation: Gunnery action between 3 units BE 6119. No further hydrophone bearing." A situation report of 2345 from C. in C. Fleet (which contained no position) showed that the battleship was surrounded by enemy forces.
At 0300 U 556 [commanded by Lieutenant Herbert Wohlfahrt] obtained a bearing of 200 degrees from BE 6153. She observed a gunnery action at 0340 bearing 230 degrees 15 miles off from BE 6164 and herself made beacon signals. At 430 she reported gun flashes bearing 230 degrees from BE 6164 left bottom. No more D/F [direction finding] bearings of Bismarck.
At 0631: Starshell bearing 270 degrees from BE 6192.
At 0700 C. in C. Fleet [Admiral Gunther Lutjens] requested that his War Logs be fetched by a U-boat. U 556, which was probably the nearest, was ordered to do this.
After all data had been re-examined, the U-boats were informed that Bismarck's position was believed to be BE 6150. This was Group Command West's assumption. I myself believed it to be further N.W. and I informed the U-boats of this possibility.
At midday U 556 reported that she would have to return because of lack of fuel. U 74 received orders to fetch the War Log instead of her.
As no further news was received which helped to clarify the situation, all U-boats taking part in the operation were ordered at 1326 to report their last sighting of Bismarck and any other observations made by them.
U 73 and 74 reported, but their observations were old and inaccurate.
At 1400 the battleship had to be presumed lost in view of English broadcasts and the situation in general. The boats were ordered at 1460 to search N.W. from BE 6150 for survivors.
This search was unsuccessful and at 1954 they were ordered to cover the following areas:
U 108 - BE 6110
U 48 - BE 6120
U 74 - BE 6140
U 97 - BE 6150
U 73 - BE 6190
At 2059 U 74 [commanded by Lieutenant Eitel-Friedrich Kentrat] rescued 3 survivors in BE 6142 and according to their statements the ship must have been sunk at about 1000 in BE 5330, i.e. N.W. of BE 6150. This agreed with B.d.U's assumptions.
All boats were ordered to join U 74 and to search from there to BE 5330. It was intended to form a searching line the next day at 0800 from BE 5330 with U 73, 74 and 48, direction 140 degrees, speed 6 knots. The present disposition of the Southern boats was designed mainly to intercept convoys, but the boats had not picked up a convoy for 8 - 9 days. I therefore decided to redistribute them in new attack areas with the object of concentrating on single-ship traffic. U 107 had reported another 3 ships totaling 21,000 GRT [Gross Registered Tons] sunk. The new attack areas are:
U 103 and U 38 South of the line Freetown bearing 40 degrees U 107 and UA [submarine commanded by Lieutenant Commander Hans Eckermann] (which is supplying today) North of this. All boats are to remain N. of 5 degrees N., E. of 30 degrees W., and S. of this E. of 25 degrees W.
Supply was requested for U 93 for May 29 in the Northern area and approved.
28.5. [28 May 1941]
U 97 is returning because of the fuel situation.
U 108 made her passage report, according to which she was still 200 miles off the position of sinking at 2100. At 0925 U 48 reported a number of floating corpses, a paravane and wreckage in BE 6141. The Biscay boats were ordered at 1041 to search the area around BE 6141 and to leeward of this. The homeward-bound Italian U-boat Barbarigo was to take part in the search according to her fuel stocks.
According to a report of 1320 from U 48 there was wreckage in BE 6141 southern half and in 6142.
At 1348 U 74 reported wreckage in BE 6145.
After consultation with C. in C. West the search was broken off at dusk on the orders of C. in C. Navy [Grand Admiral Erich Raeder], no further reports of successful rescue operations having been received by evening.
U 73 and 74 reported: search unsuccessful.
The boats continued on their passage.
U 101 left Lorient.
29.5. [29 May 1941]
The trawler Sachsenwal [probably the weather ship Sachsenwald] rescued another 2 survivors after midnight in BE 6150. Group Command West then requested, on the orders of Supreme Command of the Navy, to order U 48, 73, 101 and 108 back to square BE 61 to continue the search. The decision to search the area again carefully means that the boats will be occupied in this for at least 3 days. Boats which have been at sea for some time (U 73, U 48) will by then have used a considerable amount of their fuel. I requested that they be refueled at sea by a tanker intended for the Fleet.
30.5. [30 May 1941]
Entered Port: U 74 and 97 St.Nazaire, U 556 Lorient. U 74 was unsuccessfully attacked by an enemy submarine with a quadruple fan in BF 5534. This boat sank nothing, as she was severely damaged by enemy anti-submarine forces during her first contact with the enemy, owing to unfortunate circumstances. She then had to return, but took part in the Bismarck action for some time.
U 556: An excellent, intelligently executed patrol, with the high result of 8 ships totaling 48,000 GRT.
Commanding Officer of U 98 reported: A good patrol, executed with ability and determination. Results: 3 ships totaling 35,000 GRT, sunk, 1 ship of 5,000 GRT damaged.
UA [submarine commanded by Lieutenant Commander Hans Eckermann] reported supply completed.
31.5. [31 May 1941]
U 141 left Lorient for an operation in the Scilly Islands area. According to the results of air reconnaissance there should be constant traffic off the coast here. As far as can be foreseen prospects are favorable.
Supreme Command of the Navy abandoned further search for Bismarck survivors as hopeless. U 108, 73, 48, 101 and 75 were ordered to make for square BD 13.
U 93 reported that she had not yet found the supply ship. An attempt is being made to bring the 2 together with the aid of beacon-signals.
U 38 requested supply as soon as possible and reported her success so far as 44,000 GRT.
U 107 reported 2 more ships, totaling 9,412 GRT, sunk.
(Signed) [Vice Admiral Karl] DOENITZ.
Notes: BdU or Befehlshaber der Unterseeboote, refers to Commander (or Flag Officer) U-boats, Vice Admiral Karl Doenitz.
German map coordinates indicated above begin with two letters followed by a four digit number. Maps depicting this system of coordinates are reproduced in Jurgen Rohwer's Axis Submarine Successes of World War Two, (Annapolis, MD, Naval Institute Press, 1999): 357-366.
A German account of Bismarck's last voyage and extracts from the war diary of U-556 which was in the vicinity of Bismarck's last battle are in: The U-boat War in the Atlantic, 1939-1945: German Naval History. (London: Her Majesty's Stationery Office, 1989): 73-75.