A few hours before noon on 25 May, the radio silence was broken repeatedly. An encrypted message with the following content travelled through the air over the northern Atlantic:
Enemy radar equipment, possessing a range of at least 35 kilometres, strongly affects operations on the Atlantic adversely. Our ships were detected in the Denmark Strait, despite thick fog, and the enemy did not lose contact thereafter. All attempts to shake off the enemy failed, despite favourable weather. Bunkering at sea no longer feasible, unless it is possible to sail away from the enemy due to superior speed.
Running battle between 20800 metres and 18000 metres. The Hood destroyed by explosion after five minutes, thereafter change of target to the King George V, which turned away, under black smoke, after being hit and was not seen for several hours. Own expenditure of ammunition: 93 rounds. Thereafter, King George V only accepted battle at extreme ranges. The Bismarck was hit twice by King George V, one hit beneath side armour belt in section 13 to 14. Hit in section 20 to 21 reduced speed and caused the bow to lay one degree deeper and loss of fuel oil. The Prinz Eugen was detached in fog, when the battleship attacked the enemy ships. Own radar prone to breakdown, in particular when firing.352
The message, divided into several parts sent separately, originated from the Bismarck.353 It has been the source of many questions and the most fundamental is why it was sent at all. It hardly contained much new information for the intended recipients, Marinegruppe West and the naval staff. Even if the content had been new, it was not of such a character that the receivers could make much of it. The fact that Lütjens at all sent it strongly suggest that he still believed the British shadowed him, despite the fact that they had actually lost contact six hours earlier. On the Prinz Eugen, the signal provoked amazement. Her radio operators had intercepted most British signals and the B-Dienst had been able to interpret them. To Brinkmann and the other officers on the cruiser it seemed quite clear that the British had lost contact with the German battleship. They realized that Lütjens had not understood that he had managed to shake off the pursuers, but why was he unaware that the British had lost track of him?
One possible explanation is that the British radar signals were picked up on the German battleship. The radar worked by transmitting short radio pulses, which were reflected when they hit an object like a ship. Some of the reflected radio energy was picked up by the ship that had sent the pulses. Thus, bearing and range could be calculated. However, it also meant that the pulses transmitted had to be quite strong, as only a miniscule fraction of the radiated energy would actually form an echo to be detected. Hence, it was possible to detect transmitting radar at greater distances than the radar itself could ‘see’ something. Consequently, it could be possible that radar pulses from the British ships were picked up on the Bismarck, despite the fact that the echo was too weak to be caught on the British ships. Wake-Walker’s ships were at least 200 kilometres away from the Bismarck when the message was sent but Tovey’s ships were closer. If the Germans detected any radar pulses, they must have originated from Tovey’s ships.354
It will probably never be possible to establish the reasons behind Lütjens’ belief that the British still maintained contact, but it seems clear that Marinegruppe West was surprised by his signal. A few hours before sending the long message, Lütjens had sent a few messages with short-signal technique, which was very difficult to obtain bearings from. One of them stated that one British battleship and two cruisers still maintained contact. It caused Marinegruppe West to send a report, with date-time group 08.46. According to this message, the latest British report showing the position of the Bismarck was dated 03.13. Subsequently none of the reports contained the position of the German battleship. Marinegruppe West concluded that the British pursuers had lost track of the Bismarck, which has emphasized in the report to Lütjens. However, Lütjens does not seem to have received the report, which was sent more than an hour before his own long messag.355
The danger with Lütjens’ message was not the risk that the content could be understood by the enemy, but the fact that the bearings could be taken when such a long transmission filled the air. At the time the British could not break the codes used by the heavy German ships, at least not quickly enough to have any operational effect. However, the British wireless operators, like their German counterparts, could learn the ‘fingerprint’ of wireless operators. It was not a foolproof method, but it suggested to the British that the long signal that had been transmitted through the air originated from the Bismarck.
When the British had become convinced that the long message might originate from the battleship they had lost contact with, they plotted the bearings. Unfortunately, only two radio stations, not far apart, had taken any bearings. Both of them were located in Britain. To establish the position of the transmitter, a line was drawn from the stations that had intercepted the signal, towards the direction it had come from. Ideally, several lines could be drawn from different stations and where the lines crossed, this marked where the Bismarck was located when she transmitted. Thus, if two receivers close to each other picked up the signal, the lines drawn became almost parallel, causing a small error in the process to have significant effect on the overall precision. Ideally, bearings would be taken by receivers positioned in such a way that the lines drawn formed an angle close to 90 degrees, and preferably many receiving stations could be used to obtain greater reliability. In this particular case, no radio stations on Iceland or in Gibraltar had received Lütjens’ message.
As each receiver only had its own basic data, consisting of its own position and the direction from which the wireless signal had originated, they passed this data on to the Admiralty. Usually, the data was analysed at the Admiralty, whereupon the resulting position was sent to the units at sea. However, before this operation, Tovey had requested that only the basic data be sent to him, not the position estimate made by the Admiralty. The reason was that the Home Fleet had been provided with two destroyers equipped to take bearings. Thus, it seemed likely that Tovey and his staff at sea might be better able to correctly estimate the position, because the Home Fleet could combine the Admiralty’s data with data from the destroyers. The advantages with several, widely separated receivers, would clearly be with Tovey. However, at this time, Tovey had in fact been robbed of his two specially equipped destroyers. One had suffered engine trouble soon after leaving Scapa Flow and had to return and the other was on its way to Iceland, to bunker fuel oil. To make matters worse, its equipment for taking bearings had broken down.356
Thus, Tovey and the Admiralty had the same data to work with, but they analysed it separately. The result was two widely separated position estimates. With hindsight, we know that the estimate made by the Admiralty was close to correct and showed that the signal had been sent from a position southeast of the point where the Suffolk had lost contact. However, on the King George V, it was concluded that the Bismarck had reached a position east of the point where the Suffolk had last seen the German battleship. Thus, it seemed quite clear to Tovey that Lütjens was heading towards southern Norway or a port in Germany; a course north of the British Isles. The divergent estimates on the position of the enemy would soon have serious repercussions, but at least they allowed Tovey to cease searching far to the west.
Tovey relayed his version of the Bismarck’s position and ordered the ships of the Home Fleet to search in the area he inferred from the estimated position of the enemy. Unfortunately, relatively few ships of the Home Fleet had sufficient fuel to carry out the order. The King George V still had at least 50 per cent of her fuel oil, but most other ships had less than half their capacity. The most important ship was the Victorious, thanks to the search capacity provided by her aircraft. She was ordered to cease searching in the westerly direction, where she had been looking since dawn. Her aircraft were recalled, but one of them did not return. Bovell decided to search for it. Thus, the Victorious did not immediately set course for the new area designated by Tovey.357
As stated above, the Admiralty had reached different conclusions. Lieutenant Commander Peter Kemp at the operations department at the Admiralty plotted the position and arrived at a point further south than Tovey. The difference between the positions was so great that very different conclusions were drawn. While Tovey’s estimate clearly suggested that Lütjens was heading back towards Norway or Germany, Kemp’s calculations undoubtedly indicated that the Bismarck was heading for France. Between the two routes lay the British Isles. Kemp informed his superior, Rear Admiral Clayton, and suggested that his results should be transmitted to Tovey immediately. Clayton turned down Kemp’s proposition, as Tovey, aided by the specially equipped destroyers, probably was better helped with the basic data from the radio stations that had taken the bearings. However, within the Admiralty, Kemp’s calculation was used. Two new bearings were taken at 09.48 hours and 10.54 hours, which reinforced Kemp’s previous conclusion that the Bismarck was heading towards France.358
Force H was instructed according to Kemp’s estimates and less than an hour later the Rodney was also give similar instructions. Early on the morning of 25 May, the commander of the battleship, Captain Dalrymple-Hamilton, assembled a provisional ‘operations committee,’ in which the American assistant naval attaché also participated. Dalrymple-Hamilton’s decision was prompted by the information that Wake-Walker’s ships had lost contact with the Bismarck. A day earlier, he had left the Britannic, which proceeded west escorted by the destroyer Eskimo, and since then Dalrymple-Hamilton had focused solely on chasing the German battleship. The committee assumed that the Bismarck had been damaged during the battle in the Denmark Strait, as she left the oil trail and was presumed to have reduced speed. Also, the air attack from the Victorious might have aggravated the damage incurred. The conclusion was that she was heading towards a French port, probably St. Nazaire or Brest. This conclusion was based mainly on the assumption that the passage between Greenland and Scotland was too risky and also German airpower and submarines were believed to be better placed to support the Bismarck along the southern route. Furthermore, the Scharnhorst and Gneisenau were probably almost ready for operations, again suggesting that Lütjens headed towards a French port.359
The committee was not unanimous and it presented various alternatives to Dalrymple-Hamilton. However, at about 20.00 hours the commander decided to remain at the present position for the moment. If no new information was received within two or three hours, the Rodney would set course according to the assumption that the Bismarck was sailing towards a French port. The bearings taken from the Bismarck’s wireless signal thus came at the right moment and as soon as the Admiralty’s data reached the Rodney, the staff began to plot the position of the German battleship. The result suggested that the Bismarck was heading towards France, so the officers on board the Rodney were surprised to receive Tovey’s signal to search further north. The staff checked the plotting again, but reached the same conclusions as previously. The Bismarck headed towards France and it was considered that the Admiralty ought to correct Tovey’s signal.360
After careful consideration, Dalrymple-Hamilton decided to ignore Tovey’s instructions. The shortest route from the Bismarck’s latest known position to Bretagne was plotted. Presently, the Rodney was south of that line and Dalrymple-Hamilton set a north-northeasterly course and increased speed to 21 knots. Hopefully this would bring her to a position ahead of the German battleship. Another circumstance affected Dalrymple-Hamilton’s decision. Considering the present situation, his battleship was probably too far away if the Bismarck sailed towards Norway. However, if the German battleship was steaming for France, the Rodney could contribute in a meaningful way. Soon afterwards, at 11.58 hours, Dalrymple-Hamilton received an order from the Admiralty, instructing him to act according to the assumption that the enemy was sailing towards a port in the Bay of Biscay.361
The reasons for the plotting mistake made by Tovey’s staff are unclear.362 With hindsight it is easy to see that some mistake was made on board the King George V, but it is much more difficult to establish which mistake. Maybe strain, exertion and pressure against the clock contributed. Whatever caused the mistake, it lead Tovey to set a northeasterly course with the King George V, as was done for those of his ships that were not prohibited from continuing the operation due to lack of fuel. Although the new direction was at least somewhat less disadvantageous than the westerly direction searched along previously, every minute could be crucial and Tovey’s new course meant that the Bismarck would increase her lead.
Of course the Admiralty could have sent a signal to Tovey, correcting the mistake, but as the officers in London still believed Tovey had his destroyers with equipment for taking bearings, they refrained from doing so. When Tovey reported that he intended to search in the area further north, the Admiralty presumed he had good information backing up his decision. Thus the decision makers in London waited, but they also ordered Catalina aircraft to search the most likely routes the Bismarck would follow if she steamed towards France, as well as those she would follow if she returned towards the North Sea.363
Shortly afterwards, at 13.20 hours, another signal was picked up and bearings could be taken. This signal originated from a point where the Bismarck could be expected if she followed the route towards St. Nazaire. Armed with this important information, the Admiralty regarded its previous conclusions confirmed. Oddly, this was actually a mistake. After the long signal, Lütjens seems to have realized that the British had lost contact; perhaps the signals from Marinegruppe West had finally convinced him. He did not make any further wireless transmission. Instead, the signal intercepted by the British in fact originated from a German submarine, which just happed to be in the area where the Bismarck sailed. Thus, a pure mistake actually contributed to confirming the belief that the Bismarck headed for France.364
As Wake-Walker and Tovey spent several hours searching in the wrong direction, Lütjens gained a considerable lead. In fact, at noon on 25 May, the distance between the Bismarck and the forces of Home Fleet was so great that Tovey would be unable to catch up with Lütjens any more, at least under his own means. Speed as well as distance and the fuel shortages spoke against him. Perhaps he did not yet realize it, but only the Rodney and Force H had any chance of getting in touch with the German battleship before it reached a French port. Thus, only two British capital ships remained between the Bismarck and her destination and none of them were modern enough to engage the German battleship on even terms. In fact, all British hopes rested on the carrier Ark Royal.
While the Home Fleet spent hours searching in the wrong area, Lütjens continued on a southeasterly course. Despite the precarious situation, the voyage had thus far been quite successful. The Bismarck had sunk the largest British warship and damaged the most modern. Thereafter she had ridden out an air attack without suffering more than minor damage and then, although the crew did not know it yet, the pursuers had been shaken off. The original mission of attacking convoys would however not be accomplished.
Müllenheim-Rechberg indulged in expectations of learning more about the situation when he proceeded to the bridge. To his disappointment, he found only one officer at the bridge, Lieutenant Commander Karl Mihatsch. He was officer on duty, but did not have much more knowledge about the overall situation than did Müllenheim-Rechberg. Nevertheless, they held a small-scale council of war and agreed that the Bismarck probably would make it to a port before British forces could draw her into battle again. Their ship had gained a considerable lead and as long as she could make at least 28 knots, the enemies more to the west were hard put not to lag even further behind. The Gibraltar based Force H, believed to be heading north, was a more serious threat, but it would not be easy for Admiral Somerville to find the Bismarck. Both officers thought that the greatest menace was British aircraft. If the British had a carrier nearby, further torpedo attacks could be expected. It was imperative that the Bismarck was not damaged in such a way that her speed or manoeuvrability was impaired. If so, the British forces to the west might catch up with her and if several British warships converged on the Bismarck, chances to win were slim.365 But did the Royal Navy have a carrier close enough?
Müllenheim-Rechberg left the bridge with a stronger sense of optimism, which was soon reinforced as good news quickly circulated on the battleship: the pursuers had lost contact! The encouraging effect it had was soon taken away by the speech made by Lütjens at noon. A few minutes before noon he received a message from Raeder, in which the Grand Admiral congratulated Lütjens on his birthday and wished him further victories during the to come. Soon afterwards, the loudspeakers on the Bismarck announced that Lütjens would address the crew. Within a few minutes his voice could be heard on the shelter deck and in the compartments where loudspeakers had been fitted:
Seamen on the battleship Bismarck! You have covered yourselves with glory! The sinking of the battlecruiser Hood has not only military, but also psychological value, for she was the pride of England. Henceforth, the enemy will try to concentrate his forces and bring them into action against us. I therefore released the Prinz Eugen at noon yesterday so that she could conduct commerce warfare on her own. She has managed to evade the enemy. We, on the other hand, because of the hits we have received, have been ordered to proceed to a French port. On our way there, the enemy will gather and give us battle. The German people are with you, and we will fight until our gun barrels glow red-hot and the last shell has left the barrels. For us seamen, the question now is victory or death!366
Perhaps it was Lütjens’ intention to raise morale, but the speech had the opposite effect. Most of the crew, in particular the young and inexperienced, had believed that the battle was already won. Just like Müllenheim-Rechberg and Mihatsch they believed that a quick sail towards a French port was all that was needed. The loudspeakers had continuously informed about the enemy activities and lately it had been clear that they were far behind, virtually without any chance of closing the distance. So why did Lütjens speak of a life and death struggle?
In fact the British had virtually no chance to halt the Bismarck before she reached a French port. Müllenheim-Rechberg had remained in the after director where he had recently assumed responsibility as duty officer, allowing the seamen to attend Lütjens’ address. Müllenheim-Rechberg did not hear the speech, but when his men returned, it instantly became clear to him that the address had had a detrimental effect on the audience. Lindemann too understood the effects of Lütjens’ speech and decided to address the crew, which he did an hour later. His speech was concise and said nothing about the British forces gathering to sink the Bismarck. Rather Lindemann alleged that the British could hardly catch up with the Bismarck, which was expected to reach a French port in a short time.
The crew’s anxiety was relieved somewhat by Lindemann’s speech and afterwards another project was initiated, whose purpose at least partly must have been to encourage the men. It was decided to build a dummy funnel, which would hopefully fool British aircrews into identifying the Bismarck as a British battleship. A second funnel would be created on the flight deck, ahead of the hangar. Also the top surface of the main gun turrets was painted yellow. By utilizing metal plates and canvas, a foldable ‘funnel’ was created and painted in the same colour as most other surfaces of the ship. For various reasons, the ruse was never used, but during the process of creating it, the Chief Engineer, Commander Walter ‘Papa’ Lehmann, repeatedly went out on the deck to see how the work proceeded. He was impressed, but nevertheless worried about how it would look when the funnel was in place. ‘We must ensure that it smokes as much as the real funnel,’ he joked.
On the bridge, the joke soon became known and it was decided to take it one step further. On the loudspeakers it was ordered: ‘The off-duty watch is to report at the second-in-command’s cabin to receive cigars. They are to be smoked in the second funnel.’367
The joke amused the crew. If the responsible officers could joke like that, the situation could not be too bad. But while the activity connected to the dummy funnel caused amusement on the deck, Lehmann had a far more worrisome problem to attend to in the machinery. The hit in section XIV had finally begun to affect the battleship’s mobility. As a consequence of the flooding, the feed water to one of the turbo-generators had been polluted by salt water, a complication that might also afflict the power plants. If salt water leaked into the feed water, there was a risk that drops of water would follow the steam into the main turbines, which would have destroyed the turbine blades quickly. The feed water had to be exchanged, but as the high-pressure boilers contained large amounts of feed water, the procedure required time. After considerable exertion, Lehmann and his men succeeded in produceing sufficient feed water from the ship’s four condensers and an auxiliary boiler, so that by the evening of 25 May the situation was well in hand.368
In France, Marinegruppe West prepared to receive the Bismarck. The situation appeared brighter with every hour that passed. She had shaken off her pursuers and decrypted British wireless messages showed that several ships had returned to escorting convoys. It had not yet been confirmed that Force H was searching for the Bismarck. Somerville’s ships could just as well be at sea to protect a convoy. Comfort was also provided by a weather forecast, which indicated that a gale in the eastern Atlantic was under way. It would render British air operations, in particular from carriers, more difficult. Orders were issued to Luftwaffe reconnaissance and bomber units to stand by in support of the Bismarck as soon as she came within range of German air power. Five submarines were also instructed to take up positions along the route followed by the Bismarck. Hopefully they would be able to attack any pursuers. In St. Nazaire, the dry dock was prepared to receive the battleship and torpedo nets were placed in the harbour, to allow her to moor safely.369
After dusk, Lütjens could delight after a day without any signs that the enemy had seen the Bismarck. In stark contrast to 24 May, with the battle against the Hood and Prince of Wales, followed by the exchange of fire with the cruisers and the air attack, the daylight hours had passed as quietly as if it had been a peacetime cruise. In the afternoon, a message from Hitler had been received: ‘Congratulations on your birthday.’
Lütjens’ birthday and the ensuing night passed in tranquillity on the Bismarck, but it would come to an end. All around them, the British searched frantically to find the Bismarck and avenge the Hood. The morning of 26 May broke with a rough sea swiftly sweeping along beneath a dark greyish cloud cover. At 10.30 hours, warnings were heard on the loudspeakers: ‘Aircraft on port!’ Then the air alarm echoed in the battleship.