The intelligence which can to-day be gained from a capture can be divided into two broad classes—technical and operational. The former includes knowledge of the construction and equipment of an enemy ship; and its acquisition can greatly improve the counter-measures adopted against others of her class and type, besides assisting our own naval architects and technicians in improving their designs. By operational intelligence we mean the acquisition of knowledge regarding the enemy’s present activities and future intentions—with the purpose firstly of attacking his forces at moments of our own choosing, and secondly of avoiding engagements in circumstances where the advantage will lie with the enemy. An example of the first purpose would be the despatch of a striking force to catch an enemy surface raider at her fuelling rendezvous; while the routeing of convoys clear of waters in which U-boats are known to be lying in wait provides a good example of the second.
Several excellent examples of the immense benefits which may be derived from such captures are to be found in the annals of the 1914–18 war; and with such recent and profitable experience available to us it was natural that the Admiralty should stress the desirability of once again acquiring intelligence of that nature when, in 1939, war broke out with Germany for the second time. In particular they drew attention to the great benefits which might be derived from the capture of an enemy U-boat. British escort commanders at once took up the idea with zest; for each one of them hoped that the honour of making the first capture would fall to him. Boarding parties were formed, trained, and kept ready to leave their ship at a moment’s notice; and in every counter-attack on a detected enemy the possibility of such a chance arising was kept very much in mind. But capture of a U-boat always presented particular problems and difficulties. In the first place the primary duty of the convoy escorts always was the safety of their merchant ship charges; and it is one of the strongest traditions of the Royal Navy that no purpose whatsoever can supersede that of ensuring the “ safe and timely arrival ” of a convoy. Thus if an enemy submarine was forced to the surface during an attack on a convoy the senior officer present was at once faced by a critical dilemma. Whilst fully conscious of the tremendous advantages to be gained by capture, he could not know how grievously his adversary was damaged. Should the U-boat have suffered only slightly she might yet escape, and the escort commander’s first reaction would therefore probably be to sink her as quickly as possible, and so save the merchantmen from suffering further loss at her hands. The quickest way of accomplishing this was to ram the enemy, and there were many occasions on which this was attempted or accomplished; but such action eliminated, of course, any possibility of gaining intelligence—except that which might be obtained through the interrogation of prisoners. Although skilled interrogation could yield valuable results, and often did so, it was obviously a poor substitute for the knowledge which might be gained from the rapid search of a captured submarine. Thus we realised that although capture still remained highly important, it had to be left to the decision of the escort commanders to judge whether it could be attempted without endangering their convoys. Moreover, other factors, such as the state of the sea, critically affected the issue, and made the decision whether or not to attempt capture a matter for very nice judgement. Not only are the occasions when an escort vessel’s seaboat can be safely launched in the open Atlantic comparatively rare, but a surfaced U-boat had a sufficient turn of speed—if she managed to start her diesel engines—to escape from almost all the types of escort which we had in service in the early days of the war, except the comparatively few destroyers which we could spare for service in that capacity. Another difficulty was that, whereas a small warship’s plating was extremely thin, a U-boat’s pressure hull was remarkably tough; and ramming could therefore cause more damage to the former than to the latter. In fact the damage, and even the disablement, of little ships which did ram U-boats became so serious that, at the time when our shortage of escorts was most acute, the Admiralty issued an order discouraging the practice of ramming except in cases of extreme urgency, where failure to do so might imperil the merchantmen. This aggravated the difficulties which beset an escort commander, since gunfire, even if it succeeded in hitting the very small target presented by a surfaced U-boat, was very unlikely to sink it. There remained, however, the possibility that by the judicious dropping of shallow-set depth charges, and the use of the escort vessel’s smaller guns, the enemy’s crew, whose morale and resolution might well have suffered from earlier depth charging, could be persuaded or encouraged to abandon ship; and if that could be accomplished the possibility of capturing her at once became more favourable—if only the weather permitted the working of boats.
After the Admiralty had stressed both the desirability of capture and the danger of ramming, the broad aims of our escort group commanders became, firstly, to sink any U-boat they detected by depth charge attacks while she was submerged; secondly to prevent at all costs the escape of an enemy which was forced to surface; and thirdly to lose no chance of boarding and capturing a U-boat, provided that such action would not endanger the merchantmen. This book sets out to tell how this latter purpose was accomplished by one escort group with singular success and immense benefit to the Allied cause. But before embarking on that hitherto untold story it is desirable briefly to recount other instances of submarine captures made during the war of 1939–45.
CHAPTER II
Other Submarine Captures
1939–1945
IT ACTUALLY fell to the Germans to make the first capture of a submarine during the last war. Late in April 1940 the British Seal left the Humber to lay mines in the Kattegat. This was bound to be an exceedingly hazardous operation, especially for a submarine as big as the Seal, which displaced about 2,150 tons when submerged. In fact so grave were the dangers that the Commander of her flotilla, Captain J. S. Bethell, came specially to London from his base at Blyth to urge Admiral Max Horton, who was then Flag Officer, Submarines, to reconsider his intention to send her on such a mission. The Admiral, however, who had himself worked in those waters in the 1914–18 war, though in the much smaller E-boats, adhered to his decision; and Bethell returned north feeling depressingly sure that the Seal would never survive her patrol. Her prospects had, moreover, recently been further reduced by the occupation of Denmark and southern Norway by the Germans; for it was now certain that those shallow waters, where a raiding submarine could not seek safety in the depths, had been heavily mined by the enemy, and would also be constantly patrolled by his surface ships and aircraft.
It soon became plain that such apprehensions were fully justified; for the Seal was bombed by German aircraft soon after she entered the Kattegat on 4th May; but they did little damage. Although aware that his ship’s presence must now be known to the enemy, and that search and counter-attack were virtually certain, the Seal’s Captain (Lieutenant-Commander R. P. Lonsdale) carried on with his mission, and that same morning he successfully laid his entire outfit of 50 mines. As German records reveal that two merchantmen totalling 5,488 tons, as well as two small patrol vessels, were sunk by the Seal’s mines her sortie certainly achieved results. Hardly had Lonsdale completed his mission when he sighted a flotilla of enemy anti-submarine vessels through his periscope, and was thus left in no doubt that he was about to undergo a very dangerous hunt. The searchers were actually the German 12th Anti-submarine Flotilla, commanded by Fregattenkapitän Hans Korn.1 At full strength it consisted of thirteen UJ boats (U-Jägers or submarine-hunters), most of which were converted trawlers of 350–525 tons displacement; but we do not know exactly how many were present on this occasion. In the afternoon the Seal’s Captain saw that a number of motor torpedo-boats had joined in the hunt, and as these fast vessels were more dangerous than the converted trawlers he took evasive action. In doing so he unwittingly took his ship through a German minefield.
By 6 p.m. the Seal had not shaken off her pursuers, and her Captain therefore made another alteration of course, dived to 70 feet and stopped al
l motors. Half an hour later a heavy explosion shook her most severely. The after compartments of the submarine were flooded, and she went to the bottom in about 90 feet with her bows inclined sharply upwards. Shortly before midnight, after nearly six hours of agonising struggle to repair the damage sufficiently to enable her to escape, the crew began the fight to regain the surface. At first all their efforts seemed likely to prove vain, and as a last resort they used most of the small reserve of compressed air to blow out diesel fuel and so lighten the hull. At 1 a.m. on the 5th, by which time the Seal’s crew had almost abandoned hope of seeing daylight again, the submarine suddenly rose steeply to the surface at an angle of 30 degrees. But her predicament was indeed desperate. The electric motors were flooded, and only one diesel engine could be coaxed into moving—and that very slowly in the astern direction. As her rudder was jammed hard-a-starboard she could, moreover, only move in a circle; and the high air pressure and lack of oxygen inside the hull had reduced her crew to the point of total exhaustion. Thus her Captain’s intention to make for Swedish territorial waters, though only a few miles away, could hardly have been carried out. As, moreover, dawn started to break at 3 a.m. the Seal would only enjoy the friendly shield of darkness for about two hours, after which renewed search and attack were certain.
Shortly after surfacing the Seal managed to get away a signal to the Admiralty reporting her grievous predicament; and the reply was that, after destroying all the secret material in his ship, her Captain should regard the safety of his crew as the primary consideration. That message was, however, never received in the stricken submarine, because the crew had already destroyed the wireless sets, as well as all other equipment and documents which might have been valuable to the enemy. None the less the Seal actually carried out the Admiralty instructions, almost to the letter.
Immediately after daylight German aircraft attacked with machine guns, and inflicted several casualties. Among the wounded was the First Lieutenant. Next a seaplane landed close to the stricken and helpless Seal, while the anti-submarine vessel UJ.128,1 commanded by Kapitänleutnant Lang, came close alongside, and at 6.30 sent a boarding officer and prize crew on board. The seaplane had meanwhile taken prisoner the Seal’s Captain and a Petty Officer. Leutnant Nolte, the boarding officer, certainly acted with initiative and promptitude, his primary aim being to prevent the submarine sinking. Having assembled the remaining officers in the control room, and kept ten of her crew aboard, he went right through the submarine as far as the water-tight door at the after end of the diesel room, abaft which she was completely flooded. Her considerable trim by the stern and list to port were meanwhile steadily increasing, and the Chief Engineer warned him that he expected her to capsize within ten minutes. “ I replied,” said Nolte in his report, “ that we would then all sink together.” He next ascertained for himself that what his British prisoners had told him was true, namely that the diesel engines, as well as the electric motors in the flooded after compartment, were completely out of action, and that very little compressed air remained. Thus there was no possibility of righting the submarine by blowing the port side ballast tanks. The list had by this time become so bad that the men inside the hull, British and Germans, had great difficulty in maintaining a foothold. Meanwhile the UJ.128 had come alongside, passed a wire and taken the Seal in tow.
Nolte was fully aware of the need to search for papers and material which could be of value to the German intelligence authorities, but one of the crew told him that “ they had had plenty of time to destroy all secret papers,” a fact which he acknowledged “ to appear very probable ”; for there were everywhere signs of the thoroughness with which they had carried out that duty. All instruments had been completely demolished, and the few books and papers which he collected from inside the submarine were utterly valueless. With typical German thoroughness these were carefully listed later. They included nothing more interesting than the Wardroom Wine and Tobacco accounts, the Manual of Seamanship (which can be bought at any bookstall in England), a copy of the King’s Regulations, that well-known aid to preparation for the examination for the rank of Lieutenant entitled “ Queries in Seamanship,” and the Master-at-Arms’s Rough Report Book.
Nolte, who was evidently endowed with a sense of humour, plainly enjoyed his novel and exciting experience—and that in spite of the Seal’s crew being convinced, and trying hard to convince him, that she would sink at any moment. Thus he reported that when an officer offered him a glass of rum— “ Navy rum, of particularly good quality in England ”—he “ had nothing against drinking a glass, which tasted excellent.” When he realised that there was nothing more he could do aboard, he verified that all valves were closed and called the prisoners on deck. “ The British,” he reported, “ were very courteous, and invited me to precede them out of the ship. But I said it was unnecessary, as I already felt quite at home.” Captors and prisoners were now ferried by motor boat to the UJ.128, where the British officers were separated from their men and a preliminary interrogation took place. Beer and spirits were offered, evidently in the hope of loosening tongues; but one man who assured Nolte that “ the British Home Fleet had mostly been destroyed ” was evidently suspected of pulling his leg. The recent Norwegian campaign and the rescue of the Altmark’s prisoners by the Cossack were discussed in general terms; but nothing of the slightest value to the Germans was gained from this or from later interrogations. Some of the prisoners did, however, evidently talk a good deal more freely than should have been the case; and it gave Nolte (and probably his superiors as well) some satisfaction to be told that the British admired the performance of the German Navy in the Norwegian Campaign, “ especially in sending an expeditionary force to Norway without possessing command of the sea.”
On approaching Frederikshaven on the east coast of Denmark on the evening of the 6th May the UJ.128 turned her tow over to the salvage vessel Seeteufel. By that time the Seal’s list had increased to 45 degrees, and all three after compartments were flooded. She can only have been got in by a very narrow margin. The two wounded officers had meanwhile been taken to the hospital at Arlborg, and the Commander of the German Naval Group Command East, Admiral Rolf Carls, ordered that the other prisoners (three officers and fifty-two men) should be sent to Kiel, where further interrogation was to be carried out in the presence of Dönitz’s Chief of the Operations Division, Korvettenkapitän Eberhard Godt. As has been said, the enemy learnt little of value, except perhaps details of the operation on which the Seal had been engaged. By the 7th May the salvage authorities at Frederikshaven had got her on to an even keel; but next day she again took a heavy list to port and examination by divers revealed holes in the pressure hull. None the less by the 10th she was ready for removal to Kiel, and left in tow of three tugs. The Germans examined her very thoroughly, and the Ober Kommando Marine (?.K.M., the equivalent of the British Admiralty) ordered that she should be made seaworthy in the Germania Yard at Kiel. Their intention was to carry out trials with her, manned by a German crew; and she was commissioned into the ist U-boat Flotilla at Kiel on the last day of November. After a short period with the 3rd U-boat Flotilla in 1941 she reverted to the Base Command at Kiel, and on 31st July was paid off. She was not actually released for breaking up until the end of October 1942. Thus the British crew involved in what must have seemed to them a tragic disaster may console themselves with the knowledge that the enemy was never able to make their ship operational. It appears that the most valuable knowledge acquired from her by the Germans came about through finding six reserve torpedoes in the submarine. Once she had been damaged it was, of course, quite impossible for the crew to fire or jettison these. The German technicians who inspected them reported that the British contact torpedo pistol “ was of very good and effective design and manufacture ”; and Dönitz at once recommended its introduction into his service “ in order to overcome troubles with our own pistol.”
In the enemy’s camp there was natural jubilation at the capture of a Britis
h man-of-war, and their propaganda service quickly took full advantage of it. On our side, where the full facts could not of course be known, there was some consternation, and measures were at once introduced to make it possible to scuttle an injured submarine. So remote had the possibility of capture appeared to us that, at the time of the disaster to the Seal, none of our submarines was fitted with scuttling charges to enable them to sink themselves quickly in an emergency.1 The whole truth regarding her ordeal did not become known until the prisoners were released from captivity after the war, and the German side of the story of her last patrol also became available to us. The Seal’s Captain and the officer who became second-in-command after the First Lieutenant was wounded were then tried by Courts Martial; but in face of the evidence which the defence was able to offer against the charges of failure to engage the enemy and of allowing the submarine to fall into enemy hands, they were both honourably acquitted. We may allow that great submarine commander Admiral Sir Max Horton to have the last word on the subject. Though he was certainly not an officer who would overlook any failure in a subordinate, in the case of the Seal he considered that, lacking all electric as well as almost all motive power, and not being fitted with scuttling charges, the self-destruction of the damaged ship was virtually impossible. Finally we may remark that even had the crew succeeded in sinking her in about 90 feet of water close off an enemy coast, she could certainly have been salvaged without undue difficulty. In view of the foregoing the justice of postwar verdicts is clear beyond question.
The Secret Capture Page 3