The Silent Deep

by James Jinks

  2

  ‘The Most Dangerous of All the Services’: From World War to Cold War

  There is no branch of His Majesty’s Forces which in this war has suffered the same proportion of fatal loss as our submarine service. It is the most dangerous of all the Services. That is perhaps the reason why the First Lord tells me that entry into it is keenly sought by officers and men. I feel the House would wish to testify its gratitude and admiration for our submarine crews, for their skill and devotion, which have proved of inestimable value to the life of our country.

  Winston Churchill, 1941.1

  I merely state a fact of life when I say with Kipling, that I received neither ‘promotion or pay’ from this operation [a Cold War submarine operation]. So, with nothing tangible to show for it, and not even being allowed to mention it over the years, it is almost as if the six months concerned had never happened; leaving something of a hole in my career. When working for the church, I was sometimes addressed by the courtesy title ‘Commander’. On one occasion I overheard one secretary say to another: ‘Oh, he’s not a Real Commander!’ I had to ‘bite on the bullet’, having known a number of ‘real’ Commanders, particularly – dare I say – non-executive, who have never had the sort of responsibility or experience that I had on those patrols. In those days, it was probably the closest one could get to a real operational command experience, outside an actual ‘shooting war’.

  Lieutenant Commander Alfred Roake, Royal Navy, recalling a Cold War operation he conducted while CO of HMS Turpin 1994.2

  VICTORY

  The cost of the Second World War to the Submarine Service in terms of both human life and equipment was vast. Whereas the casualty rate in the surface Navy was 7.6 per cent, in the Submarine Service it was 38 per cent.3 Very few submariners who witnessed the start of the war lived to see it end. Between 1939 and March 1945, 3508 submariners perished or were captured, over a third of the 9310 that served in the 206 Royal Navy submarines that put to sea. Seventy-four of those submarines never returned from patrol; in the Mediterranean alone, where a single submarine was, in the words of the First Sea Lord, Admiral Sir Andrew Cunningham, ‘worth its weight in gold’, forty-six were lost between 1939 and 1945.4 But when the war in Europe ended, the Navy quickly concluded that it possessed far too many submarines: 142 were either in service or under construction.5

  In May 1945, the head of the Submarine Service, Admiral Submarines, Sir George Creasy, recommended reducing the size of the fleet to 100 by scrapping or expending as anti-submarine targets virtually all of the older ‘H’, ‘L’, ‘O’, ‘P’, ‘R’ and ‘U’ class submarines, while keeping the newer ‘S’, ‘T’ and ‘A’ class for post-war service. But the sudden return to peace, the onset of post-war austerity and the recognition that the United Kingdom had emerged from the war in a seriously weakened position forced Creasy to recommend suspending construction of fourteen of the new ‘A’ class submarines, leaving just twelve in the programme, and suspending three ‘T’ class submarines then under construction and scrapping nine old or badly damaged submarines of the class. When the war against Japan ended in August 1945, Creasy recommended additional reductions, from 100 to 85 submarines, consisting of 12 ‘A’ class, 27 ‘T’ class, 37 ‘S’ class and 9 ‘U’ class, with 45 in commission and 40 in reserve.6 In April 1946, these numbers were once again revised downwards to just 73, with 45 in full commission and 28 in reserve (manned by a one-third crew and refitted every twenty months).7 Four Second World War era midget submarines, ‘XE’ class, were also retained.

  By the following year all the small ‘U’ class submarines had been disposed of.8 Some 66 submarines were still on hand or about to be delivered, 25 ‘S’ class, a similar number of ‘T’ and 16 ‘A’ class. As the Director of Naval Construction had minuted in 1945, the ‘S’ class were based on ideas sixteen years old, the ‘T’ class on ideas ten years old and the ‘A’ class on ideas three and a half years old.9 These submarines were essentially surface vessels with the capability to submerge. They were slow, unmanoeuvrable when submerged and could only remain so for limited periods (measured in hours, depending on the speed at which they were travelling), having to surface periodically to run the diesel engines that recharged batteries and replenished air supplies. Submariners, particularly those who operated in the Far East against the Japanese, knew how outdated their submarines were, especially when they were compared with the US Navy’s fleet.10

  Towards the end of 1944, Creasy had spent three months considering ‘the problem of the future design of the Submarine after the war’. He was ‘swayed by the developments in the U-boat campaign’ in the North Atlantic as well as German submarine tactics and technology. At the outbreak of the Second World War the Royal Navy successfully exploited a new underwater detection device, an early form of sonar known as ASDIC (named after the Anti-Submarine Detection Investigation Committee) to detect German U-boats. Although Churchill later claimed that ‘The U-boat peril’ was the ‘only thing that ever really frightened me during the war’, the Allies succeeded in exploiting the one major weakness of the U-boat: its need to operate on the surface at frequent intervals to run diesel engines and recharge batteries. Each time a U-boat surfaced it was vulnerable to attack from nearby surface ships and aircraft.11 Between 1940 and 1942 Allied anti-submarine operations were so successful that Germany’s U-boats were forced to adopt a campaign of night surface attacks, with multiple U-boats working as packs, moving ever further afield hoping to stretch Allied forces to breaking point. By 1943, Allied anti-submarine detection and destruction methods were having such a serious impact on the U-boat campaign that in a desperate attempt to reduce their losses the Germans turned to a Dutch device known as the Schnorkel.

  The Schnorkel was a piece of equipment consisting of a raised mast through which air could be drawn into a submarine when it was submerged and operating at periscope depth. The new device allowed German U-boats to stay submerged for extended periods of time while running diesel engines. Fitted originally as a defensive measure to reduce the chances of detection by Allied aircraft and surface ships, U-boat crews quickly realized the offensive potential of the Schnorkel and used it to return to waters near the UK mainland in which they had not operated since the early years of the war. Having been driven below the surface by the weight of Allied anti-submarine countermeasures, the Schnorkel-equipped U-boats started a new offensive, a true submarine campaign. ‘As a “submersible” the U-boat has been defeated,’ noted Creasy in November 1944, ‘but as a “Submarine” it has returned to the attack.’12

  The Schnorkel had a notable impact in the closing months of the Second World War. In November 1944, the Director of the Anti-U-Boat Division, Captain Clarence Howard-Johnston, concluded that:

  The Schnorkel has had such far reaching results that the whole character of the U-boat war has been altered in the enemy’s favour. Frequently he has managed to penetrate to and remain on our convoy routes in focal areas with impunity in spite of intensive air and surface patrols. With more experience in training and with the confidence engendered by his present immunity from air, and often from surface attack, he is likely, in the future, to do us more real harm than he has up to the present.13

  The war ended before the Germans could exploit the full potential of the new equipment.14 But the Royal Navy recognized that it was ‘evident that the advantages to be gained from the use of the device are very great’ and that there may come a point when it was necessary to equip its own ‘submarines with “Schnorkel” at short notice for which we must be prepared’, but it stopped short of adopting the new device in the final months of the Second World War on anything but a very limited basis. This was because, as Howard-Johnston explained:

  On our side, our Submarines have, happily, never been called on to face any comparable scale of Anti-Submarine Defence, either in weight of numbers or in efficiency of material or personnel. Thus, we have been able to pursue the tactics of diving by day and surfacing by night which have
been the basis of Submarine operations since the earliest days of our Submarines. In effect, our Submarines have always operated as ‘Submersibles’ and continue to do so.

  Creasy too argued that the Schnorkel:

  In its present form has several weaknesses … e.g. space and weight inside and outside the submarine, inability to operate in rough weather, considerable discomfort, not uncoupled with danger, to personnel. Apart from the raised morale the ‘Schnorkel’ bestows, by increasing the submarine’s chances of survival, it is thought that it will tend to make the submarine captain feel unsafe when it is not being used. This has the direct effect of encouraging submarines to remain submerged, even when it is unnecessary for them to do so, and thus by decreasing their mobility decrease their offensive spirit and power to inflict damage. Results to date seem to indicate this state of affairs.15

  Creasy recognized the long-term significance of the Schnorkel. He knew that ‘Inevitably the day will come, sooner or later, when the Anti-Submarine efficiency of our enemies reaches the point which we have already achieved.’ But he was far more concerned with ‘the problem of the more distant future’ as he could see ‘no development in prospect that would restore to the “Submersible” its surfaced ability’.16 He recommended that experimental Schnorkels, given a British title, the ‘snort’, should be fitted in one ‘U’, one ‘S’, one ‘T’ and one ‘A’ class submarine, ‘as soon as it is possible to forecast when they will be required’, but that the Royal Navy should wait until it had gained more practical operational experience before equipping its entire submarine fleet.17

  On 11 January 1945, Creasy assembled the senior Admiralty Staff involved in submarine policy at the wartime headquarters of the Submarine Service at Northways House, near Swiss Cottage, London, to discuss ‘The Future Development of the Submarine’. A paper was tabled that outlined three types of future submarine:

  (a) A craft with the maximum surface speed, endurance and armament and the best submerged performance and armament that can be achieved, subject to the surface requirements.

  (b) A craft with the maximum submerged speed, endurance and armament and the best surface performance and armament that can be achieved, subject to submerged requirements.

  (c) A compromise of (a) and (b) with the best alternative combinations of surface and submerged speed, endurance and armament.18

  The biggest problem was the requirement for maximum submerged speed and endurance. In order to design and build a submarine that met these needs a new type of power plant was required, one that could generate great speeds while allowing a submarine to stay submerged for extended periods. But, as the paper pointed out, ‘the production of a propulsive unit around which the future submarine must be designed does not, at the present time, appear to be possible for some years’. This did not mean that other features of a future design could not be developed by using existing means of underwater propulsion, such as diesel engines and batteries, to produce experimental submarines in which to test future designs and equipment. The paper argued that it was ‘essential that development of other factors, and in particular the hull form and its attendant problems, be advanced to such a stage that there is a minimum of delay in building the prototype future design, when a suitable type of power plant becomes available’.19

  The Admiralty had already embarked on some experiments, principally by adapting one of the Royal Navy’s ‘S’ class submarines, HMS Seraph, as a fast underwater experimental submarine. Trials with Seraph had shown that ‘the building of a craft with special hull form, much increased battery capacity and high power motors, increased diving depth and specially designed control gear is a possible and immediate requirement’.20 Long-term policy became to proceed with experiments and investigations with a view to developing a true submarine, one that could stay submerged for long periods, while in the short term continuing to develop the submersible.

  When the war ended the Navy paused its investigations into future submarine designs and started to examine captured German submarine technology. Aside from the Schnorkel, the Navy was interested in two additional German submarine developments.21 The first was a new class of U-boat, known as the Type XXI, designed to operate submerged for prolonged periods of time, thus evading Allied anti-submarine detection efforts. It was superior to the Royal Navy’s submarines with respect to sonar, underwater speed, depth capability and torpedo reload interval, and was fitted with powerful batteries as well as a distinctive streamlined hull which had a rubberized (anechoic) covering to reduce detection from radar on the Schnorkel head and active sonar on the hull.22 With the ability to approach Allied convoys, attack and evade pursuit at high speed, the Germans hoped that the Type XXI would render obsolete Allied anti-submarine methods which had so effectively countered its existing U-boats.

  In 1943 Hitler ensured that the Type XXI construction programme was awarded the highest priority. Albert Speer, the German Minister of Armaments and War Production, brought in Otto Merker as the head of the German Central Board for Ship Construction, who used his experience from the automobile industry to radically reduce the amount of time required to build the submarines by constructing them in eight prefabricated sections which were then fitted together on an assembly line.23 In late 1943, the head of the German Navy, Admiral Dönitz, placed orders for 170 Type XXIs, and although over 120 were constructed, design faults, manpower and material shortages, shortcomings in design and production, as well as a relentless Allied bombing campaign against German shipyards which damaged many of the prefabricated sections while they were being fitted together on the slipways meant that only one Type XXI, U-2511, conducted a war patrol. Although this was far too late to have any decisive impact on the outcome of the war the British recognized that the Type XXI ‘was a formidable weapon which would have given us a lot of trouble. Nor was it the last word, as submarines of still greater under-water speed were being developed by the Germans.’24

  Since March 1943 British intelligence had been receiving reports (of varying reliability) about new high-speed submerged U-boats powered by a revolutionary method of propulsion that had the potential to transform submarine warfare. In April 1945 naval intelligence reported on the development of the small Type XVIIB and the larger Type XXVI U-boats, both powered by the Walter gas turbine propulsion unit and capable of producing underwater speeds in excess of 20 knots, fast enough to outrun any surface ship or submarine attempting to protect a convoy. Mindful of the potential threat, the British and the Americans went to extraordinary measures to capture the new U-boats, specifically two of the Type XVIIBs, U-1406 and U-1407.25

  THE SPOILS OF WAR

  On 4 May 1945, the Royal Navy’s secret intelligence group, 30 Assault Unit, entered Kiel and proceeded towards an industrial facility known as the Walterwerke, where a German scientist, Helmut Walter, was working on the experimental U-boats. Despite extensive bombing by the Allies, the Walterwerke was around 90 per cent intact. 30 AU quickly apprehended Dr Walter, who was living next to his plant. A ‘rather heavy, flabby-cheeked man of 45’, Walter had joined the Nazi Party in 1932 and became a leader of industry in Kiel.26 Initially unwilling to divulge the details of his work, Walter only started speaking when Admiral Dönitz, who was by now Hitler’s designated successor as Führer, ordered him to disclose everything. ‘The effect was instantaneous, and from that day, May 7th nothing (one hopes) was kept back.’27 His interrogator wrote that ‘It lurks constantly in the writer’s mind that he may even yet prove to be one of the sinister crooks of international fame who features so often in filmed fiction.’28

  Walter’s views on submarine design were very advanced. He told his interrogators that he foresaw that the submarine of the future would only operate submerged and that, in war, there was no future for a submarine on the surface operating away from its base.29 He advocated subordinating all surface qualities in order to obtain optimum submerged capabilities, including the provision of any guns as they made the bridge too big and marred the streamlined shap
e of the submarine. He had given the bridge design ‘ruthless consideration’ and argued that it should only be of sufficient size to house the periscope, compass and radar.30 His views on torpedoes were revolutionary. Stern torpedo tubes, he said, should be unnecessary because of the speed with which a submarine would be able to turn and the additional congestion involved. Walter was obsessed with speed, insisting that any future submarine should be capable of 25 knots in order to outrun escort vessels. He even maintained that submerged speeds of up to 30 knots were achievable.

  To achieve these speeds Walter had developed a revolutionary method of propulsion, a closed-cycle system, based on the decomposition of highly concentrated hydrogen peroxide (HTP), which was decomposed to produce steam and oxygen at high temperatures and then combined to ignite diesel oil. Water was then sprayed to cool the temperature and produce steam, which then was used to drive turbines, while the remaining water and residual carbon dioxide were transferred into a condenser before being exhausted.31 Four Type XVIIA U-boats had been commissioned into the German Navy in late 1943 and early 1944 to prove the technology. While they were successful – one U-boat, U-792, achieved speeds of 25 knots – they suffered from significant mechanical problems and poor reliability. Despite these deficiencies, construction of operational U-boats, known as the Type XVIIB, started in mid-1944. Only three, U-1405, U-1406 and U-1407, had been completed by the time the war ended, and while work on larger XXVI U-boats had also started at the Blohm and Voss shipyard, none were anywhere near complete when it was occupied by the Allies.