The after single 15cm TK C/36 guns of a destroyer.
The post-World War I Reichsmarine continued to use the term ‘torpedo boat’ for surface warships displacing less than 800 tonnes and carrying torpedoes as their primary armament, and it was not until the first true destroyers were under construction, from 1934 onwards, that the term Zerstörer(destroyer) came into vogue in Germany. The lost war brought the dissolution of the Imperial Navy, and Germany was obliged to surrender as reparations large parts of her Fleet— generally the most modern units. Most of these found a watery grave as a result of the mass scuttling at Scapa Flow in 1919, and this bravado had to be paid for by handing over or scrapping further ships.
On 16 April 1919 the Germans were instructed to set up a ‘Provisional Reichsmarine’, a measure legitimised by the elected Reichstag on 30 July 1920, and the Wehrgesetz (Armed Forces Law) was passed on 23 March 1921. The scuttling of the High Seas Fleet at Scapa Flow on 21 June 1919 was a direct consequence of the dictated terms of the Versailles Treaty. As regards torpedo boats and destroyers, Article 181 stipulated that a future German Navy might have no more than sixteen destroyers and sixteen torpedo boats, four of each being in reserve. Article 190 laid down that when any of these boats* was fifteen years old—calculated from the launch date—it could be replaced by a new vessel, but a new German destroyer was not to exceed 800 tonnes, nor a torpedo boat 200 tonnes. This latter requisite was a step back into the nineteenth century, for it had been the tonnage of the very first torpedo carriers. The size and type of armament, including mines and torpedoes, ammunition and equipment, were subject to the inspection and approval of the victorious powers.
The Treaty of Versailles made it impossible for Germany to keep abreast of modern destroyer construction. Whichever way one looked at it, an 800-tonne ‘destroyer’ was a torpedo boat. Nevertheless, the Reichsmarine was obliged to respect the limit with its first new boats, and thus there came into being, in compliance with Versailles, twelve ‘destroyers’, the six vessels of the Möwe class ordered in 1923 (Möwe, Seeadler, Greif, Albatros, Kondor and Falke) and the six Wolf class ships ordered in 1924 (Wolf, Iltis, Luchs, Tiger, Jaguar and Leopard) carrying three 10.5cm (4.1in) guns—the originally intended 12.7cm (5in) armament having been disallowed—and two triple sets of torpedo tubes. Speed was about 33 knots.
Personnel
Article 194 restricted the future German Navy to a personnel strength of 15,000 men, of which no more than 10 per cent could be officers or specialist deck officers, who had to be career sailors serving the colours for 25 years. NCOs and ratings signed on for twelve years. If one thinks of the numbers employed at Staff level and in the numerous shore bases alone, it can be seen how few were left to man the ships—which explains why there were so few vessels in commission in the earlier years. With the arrival of the new light cruisers and the twelve new torpedo-boats in the mid to late 1920s, the personnel situation became desperate, and as early as 1924–25 the first attempts were made to introduce a clandestine short-term volunteer force of 600 men contrary to the Versailles Treaty. The SPD (Social Democratic Party) ensured that nothing came of this.
In the naval rebuilding plan of November 1932, the Reichswehr Minister approved an increase of 1,450 lower rates in the standing force and expressed the urgency for the officer corps, and the manpower situation generally, to be strengthened. Staffing was the most important naval question, but it was not until the declaration of military sovereignty in March 1935, and the signing of the Anglo-German Naval Agreement three months later, that the way was cleared to resolve the problem. From this point, however, time was of the essence, for Fleet rearmament was continuing with haste, and this adversely affected the training of the new generation of military seafarers. The Warrant Officers Corps—formed from the erstwhile ‘deck officers’ of the former Imperial Navy and the backbone of the Fleet—had been broken, and the best of them (and there were many) had been given commissions. Thus a new and well-qualified NCO corps had to be trained, but time for schooling ashore, and training aboard ship, had to be cut back ruthlessly. This applied to all ranks.
Referring to a speech he made on 21 September 1934, Admiral Raeder remarked, ‘Promotions permitting, all appropriate servicemen in their twelfth and last year of service with the Reichsmarine [the contractual period for professional naval men] were kept back. The personnel situation was especially tight in 1935. The shortage of destroyers and torpedo boats in commission in 1937 was directly attributable to our lack of personnel in certain career fields (particularly engine room, radio and signals and weapons). This had its effect on the completion of new ships, the commissioning of numbers of which had to be postponed.’ There were shortages everywhere, and there was no time to strike the necessary balance between quality and quantity. It was symptomatic of a Wehrmacht in a fast and impetuous reconstruction in a relatively pleasant period of peace. On the outbreak of war, these gaps would open up painfully.
Applications to join the Navy were insufficient, and the quality of officer candidates in the two or three years before the war had deteriorated markedly as evidenced for example by a report, H.11202 Ia: ‘Education and Training of the October 1938 Officer Candidate Entry’, signed by Vizeadmiral Schuster, Head of the Naval Training Inspectorate at Kiel and issued on 17 July 1939 to, inter alia, the commanders of all destroyers, torpedo-boats and E-boats, in which he remarked that pre-military training in the RAD (compulsory six-month labour service), Hitler Youth and Naval Hitler Youth had not borne the desired results: ‘Whereas the generally very good physical assessment, the interest in sports, physical efficiency, sense of comradeship and, amongst a number of candidates, the desire to serve, toughness and goodwill must of course be recognised, with a relatively large number of them it has, nevertheless, needed a protracted effort to get them to appreciate the moral demands made of the soldier, in particular the need for the uncompromising fulfilment of all—even the most insignificant—duties. A number showed great skill in evading unpleasant tasks and adopted from the outset a highly critical attitude. What was lacking here, primarily, was the ability to integrate unconditionally and a respect for authority and their seniors, coupled with an inability to take heed of warnings and advice.’ Conceding that the 1938 entry was better than that of the year before, Schuster concluded that ‘the young candidate of today does not always possess those attributes and character values which were generally considered in the past to be a precondition for admission as a Wehrmacht Officer Candidate. This is undoubtedly due to the relatively high admission quotas of recent years in which candidates were successful where in earlier years they would have been rejected. Moreover the “Führer problem”—especially in the Hitler Youth—has not been resolved. As regrettable as it may be to say so, we do have to allow for that in training.’ In conclusion, the writer advised the commanders of vessels that cadets showing ‘gross character defects, a negative disposition towards the military calling allied to a delight in criticising, an adverse influence on comrades, a continuing standard of under-achievement due to retarded physical or psychological development, a lack of interest and indifference, a lack of pride, enthusiasm or self-confidence, denigration of those in authority over them and failure to follow orders’ were to be weeded out and failed as officer candidates. This document throws an intriguing light on the situation regarding personnel in the Kriegsmarine shortly before the war and shows how burgeoning rearmament—in every sense of the word—had resulted in a deterioration rather than an improvement in the quality of human resources.
The same story was repeated amongst promotion candidates in the lower rates. At least two years before the war the training of engine-room personnel at the naval technical schools and other educational institutions had been deteriorating. The pace of rearmament was forcing reductions in the time allowed for training: for example, in 1928 an officer spent 26 months under instruction ashore and 28 months in shipboard training before receiving his commission, but by 1938 this had been reduced to thirteen months ashore and eighteen afloat. During the Second World War a month was clipped off both periods. In 1938 there were 1,800 seaman branch officers, 475 engineer, 26 medical officers, 130 administrative officers and 1,025 Ergänzungsoffiziere (a supplementary officers’ corps time-served in the Reichsmarine and re-contracted to the Kriegsmarine). These 3,876 officers amounted to 5.8 per cent of a Kriegsmarine numbering 56,000 men. Whereas engineer NCOs of the Reichsmarine spent a three-year apprenticeship afloat and could then be selected for further training, in 1938 the shipboard training period averaged only a year, and about 48 per cent of trainees were selected for further NCO training. Even the shipyard construction familiarisation course was counted as time afloat.
The situation was worse for warrant officers. To fill the gaps left by promotions, the contracts of the veteran warrant officers were extended and the training of suitable junior NCOs accelerated. In the last two years before the outbreak of war in particular, there was a continuous change-round of personnel. This took place practically every six months and affected about 25–30 per cent of naval personnel overall. At watch and battle stations the changeover involved 50–60 per cent.
The destroyers, with their overcomplicated machinery, suffered particularly, and this problem continued into the war. Between September 1939 and October 1940 the destroyer Z 10 Hans Lody took part in seventeen operations, and during this period the engine room had a turnover of 100 per cent of the officers, 41.6 per cent of the warrant officer ERAs, 34 per cent of the NCOs and 62.3 per cent of other rates. On 23 September 1937, in Report 5713M to the BdA (C-in-C Cruisers) entitled ‘Training in Boiler Rooms’, Kapitän zur See Kummetz, FdT, wrote, with reference to two earlier papers: ‘The aim of training is to release boiler-room watchkeeping NCOs from supervising any particular machinery or valve, for only then can they accept full responsibility for the room. This aim is coming up against the greatest difficulties because of the physical layout of boilers and the inaccessibility of the installations: (a) The boiler rooms are too small. Particularly restricted is the control stand from where individual pieces of auxiliary machinery and valves are so inaccessible that the instruments have had to be repositioned on a board because they could not be seen. (b) It is impossible to see the fire in the Saacke burners from the central position. The feedwater regulators do not work automatically and the water level has to be controlled almost constantly by hand. The lubrication of the boiler supercharger is poor, and it is necessary to shut down the supercharger at 800rpm to permit some degree of lubrication to be carried out. Parallel running of superchargers is not possible because there is no common steam valve. If setting up the changeover for operating the supercharger valves takes too long, they run separately and have to be constantly regulated manually, (c) About 20,000hp is housed in each boiler room. The installation is comprehensive and complicated. The vast and rapid changes in pressure require correct handling of these modern boiler systems by highly qualified personnel who understand the interrelatedness of steam pressure, feedwater supply, superheater temperatures and airflow and have the practical experience enabling them to identify and rectify problems as and when they arise. The prescribed staffing level for each boiler room is one NCO and four stokers. Because the feedwater regulator is so inaccessible, two stokers have to be at the central stand at all times. One stoker has to be ready to shut off the water level and regulate the supercharger atomiser, while the other waits to close down the burn valve immediately should the Saacke burner flame go out since there is then a risk of explosion. The 1+4 staffing is insufficient to guarantee the safe working of the boilers under all conditions.’
The report then described in detail the problems encountered operating the three modes—automatic, semi-automatic and manual. Kummetz concluded: ‘Running the boilers manually requires one NCO and six men. The idea of having one man replace the NCO so that he is free in the sense suggested in OKM paper 7340 A IVg of 3 December 1936 is impractical: what is needed is an additional NCO for each boiler room. However, all attempts to introduce this measure aboard destroyers have foundered on the accommodation problem. To summarise: because of the present layout and inaccessibility of the boiler plant, the boiler-room NCO is tied to the control stand precisely as is the NCO at the operating valve of a main engine, and especially when operating the boiler manually. The present staffing level of 1+4 per boiler room is too low. The only alternative would be to broaden training, particularly as regards semi-automatic and manual operation, in a calm training atmosphere, for which up to the present little or no opportunity existed.’
On 2 November 1937, Korvettenkapitän Max Fechner, Commander of Z 6 Theodor Riedel, stated in Report B 752, addressed to 2nd Destroyer Division Command at Wilhelmshaven and referring to Fregattenkapitän Kummetz’s paper, that the possibility of releasing the boiler-room NCOs had not been satisfactorily achieved because of ‘the inexperience of NCOs, the too brief training period generally and deficient technical instruction of auxiliary machinery operating procedures’. Although criticising some aspects of the FdT’s report—particularly the high level of expertise suggested for NCOs (marginal note in the report: ‘O-ho!’)—and pointing out that there was no need to have all four Saacke burner flames in full view of the central stand at all times, Fechner also concluded that at least one extra man was essential for each boiler room. This would mean an increase of nine in crew numbers, and six of these would have a secondary task of acting as ammunition handlers in combat, but accommodation difficulties could not be avoided.
Both reports mentioned the too-brief training (the result of the forced pace of naval rearmament) and the lack of personnel. Destroyers and their crews were granted only a few years and months of peace. At the outbreak of war many were undergoing trials and working up; others had terminated the prescribed training and were joining the Fleet; and some had taken part in manoeuvres and exercises, even in the Mediterranean. However, the crews were always being chopped and changed, and disruption prevailed: as new destroyers became available, veteran sailors were transferred to them to form the core company, leaving raw, inexperienced men to be trained from the very beginning as replacements.
All was flux, with no period of consolidation. That may have been in some ways justifiable for the seaman and specialised branches such as telegraphy, signals and gunnery, but in the engine rooms the highly developed boiler and turbine systems, linked up to numerous units of auxiliary machinery, often of different manufacture—virtually the entire engine-room domain—demanded a highly qualified workforce and practical training to provide it. In peacetime, these courses lasted for months. When war came, training went by the board, for men were needed to crew the ships. They stood their watches at sea in filthy weather or, when aircraft could get up, kept watchful eyes on the sky from where the chief danger was increasingly liable to come and which was to take a high toll in their blood. Meanwhile, below decks, the engineering branch showed an unflagging devotion to the job of keeping the machinery running despite the ever-increasing number of breakdowns. The concept of ‘service’ took on a new meaning: everybody was seized by the ambition to keep his own corner up and running. The exigencies of the service—interrupted only rarely for periods of rest and recuperation—drove men to the limits of physical and mental endurance. What they accomplished during the war years in the narrow, twisting confines of these destroyers, particularly towards the end of the war in the conscious knowledge that it was lost, was remarkable and speaks well for the comradeship aboard each individual ship.
The total number of shipboard deaths on board German wartime destroyers was about 2,600. The last Flag Officer Destroyers and Torpedo Boats, Vizeadmiral Kreisch, took leave of his men on 10 May 1945 with the following Order of the Day: ‘Following completion of your final mission, I thank you, my dear comrades, for your proven readiness for action and for your loyalty and comradeship over six years of war. Our proud war flag flew during many famous and victorious voyages. Five thousand of our comrades fell aboard our boats. Long live the Destroyer and Torpedo Boat Arm!’
The Destroyer in German Naval Strategy
The Treaty of Versailles had prohibited the building of German warships in private yards. As Danzig no longer formed part of the German Reich, the Kaiserliche Werft there closed its doors, while its subsidiary at Kiel was split up into the state-owned Deutsche Werke and the Naval Arsenal, the latter now being the Reichsmarine repair yard. The other subsidiary, at Wilhelmshaven, became the naval shipyard, and the Uto Yard at Wilhelmshaven was transferred to the control of the Deutsche Werke.
Germany retained seventeen large torpedo boats (two in reserve) and sixteen small torpedo-boats (four), and the ages of these remaining Imperial Navy units was so close to the fifteen-year mark that a start could be made almost immediately on the construction of replacement units—as was the case with the light cruisers. The shipbuilders would be Wilhelmshaven Yard and, under certain conditions, Deutsche Werke at Kiel. The early start in the warship rebuilding programme—the light cruiser Emden leading the way—suffered a violent setback in time as a consequence of the developing hyperinflation and devaluation of the German currency. The Washington Naval Agreement signed by the five major powers (the United States, Britain, France, Japan and Italy) in 1922, aimed to limit the naval arms race, especially with regard to capital ships and cruisers. Germany was not invited to attend this conference, which decided amongst other things the numbers and sizes of future warships based on displacement. The Imperial (or long, or Washington) ton—equivalent to 1,016kg— became the basis of a ship’s standard, or type, displacement. This standard displacement was the weight of the ship equipped to sail, with all ammunition and armament, her machinery ready, plus water for the crew, in boilers and in piping but excluding fuel and feedwater. The previous standard as understood by German naval architects, designed displacement, had also included approximately one-third to two-fifths of the fuel and water aboard. The effects of the two changes for smaller warships gave German naval architects a few extra tonnes to play with.
By 1925 twelve former Imperial Navy torpedo boats declared by Germany as ‘destroyers’ under the Versailles Treaty became due for replacement. The designs, to a standard displacement of 800 long tons, began in 1923. That few former Imperial Navy naval architects remained in harness influenced the decision to place orders for the new vessels with Wilhelmshaven rather than the Deutsche Werke at Kiel.
The 1930 London Naval Conference had set a binding maximum destroyer displacement at 1,830 tonnes, with an armament calibre not exceding 13cm (5.1 in). Two years later the disarmament talks in Geneva held by members of the League of Nations proposed that all nations should disarm. As a result of Versailles, Germany had been forced in that direction and was prepared to make further concessions (for example, to renounce the construction of large Panzerschiffe—the pocket battleships of the Deutschland class). As the major powers—in particular the victors in the Great War—were now split into two mutually antagonistic camps preparing to fight each other, the conference broke up on 2 February 1932 without having achieved its purpose, and on 26 July that year Reichswehr Minister Schleicher announced that Germany no longer felt bound by the Versailles Treaty. On 15 November 1932 the rebuilding plan for the Reichsmarine was approved, and this was expanded by the National Socialists after their seizure of power in 1933. A homogeneous fleet was proposed, including six half-flotillas of destroyers or torpedo boats. On 19 October 1933 Germany left the League of Nations.
The first designs for pure destroyers had been invited in 1932, and two shipyards, Stettin Vulcan and Schichau, submitted plans. Stettin proposed an 1,100-tonne vessel capable of 35 knots and armed with three 12.7cm (5in) and four AA guns and two triple torpedo sets. The Schichau sketch, for a 1,500-tonne ship with a speed of 38 knots and mounting four 12.7cm guns, bore strong similarities to the final Type 1934 destroyer, although all vessels were built to official designs signed by the Kriegsmarine Naval Architects’ Office. The Type 1934/1934A was developed from the 1932 sketches, and the various Types 1936 from the official designs drawn up that year.
The signing of the Anglo-German Naval Agreement on 18 June 1935 cleared the way for the first true destroyers. Germany was permitted a destroyer fleet of 52,200 tonnes, on which work was commenced at once. According to the 1932 Fleet Rebuilding Plan, OKM declared its intention to build sixteen destroyers with a standard displacement of 1,625 tonnes and a 12.7cm main armament. The Treaty of Versailles now ignored, Germany decided to observe the Washington (1922) and London (1930) Treaties instead.
Destroyer construction proceeded according to the Plan, but in making up for the lost time between 1918 and 1935 the work was rushed and, under close examination, appears not to have been well thought out. Initially six destroyers were expected to be laid down, but eventually Deutsche Werke at Kiel received building contracts for the first destroyers, Z 1 to Z 4. These were Type 1934, with an official standard displacement of 1,625 tonnes. Specifications included great strength of hull, good seakeeping qualities, a high maintained speed (even in heavy seas), a large radius of action and a powerful armament. The purpose of the design was to provide a fighting vessel which could double as a small cruiser—a type in which the German Navy was deficient—exceeding the 1,378-tonne French and 1,540-tonne Polish counterparts (these nations being the presumed potential opponents in war). This line of reasoning explains the jump in displacement for tendered destroyer designs from 1,100 tonnes to 1,500 and even 1,800 tonnes.
The specifications imposed by the Kriegsmarine became ever more comprehensive. The 1934 Shipbuilding Replacement Plan, which spoke of 48 destroyers, was discarded by the Admiralty Office in May that year in favour of ordering four more destroyers, followed by a building pause of two years. Doubts had been voiced during the yard work about the projected seakeeping qualities of the first four ships in high seas or heavy swell. The shortish foredeck and the poor lateral flare of the frames forward had come under particular scrutiny, for this was an area where the torpedo boats and the light cruisers Karlsruhe, Köln and Königsberg had all demonstrated weaknesses. Accordingly, it was decided to introduce modifications to the second series of four ships involving a redesign of the foreship and forecastle frames, and so the Type 1934A showed a number of improvements to the original plans. Z 5 to Z 8 were built in the private yard at Deschimag (AG Weser), Bremen.
Over the next few years the Office of Naval Architecture filed many modified plans for destroyers of different sizes and armament, but the design of a really useful type within the 1934 specification eluded them. All this endeavour might profitably have been invested in settling for a good standard type. Z 9 to Z 13 came off the stocks at Germania Werft Kiel and Z 14 to Z 16 at Blohm & Voss Hamburg. The Type 1936, Z 17 to Z 22, was outwardly different and displaced 1,811 tonnes. The ships were completed at Deschimag, the yard which stood at the forefront of destroyer construction. All subsequent vessels (except Z 37 to Z 39) were built there—Types 1936A, 1936A(Mob) and 1936B (Mob), plus the diesel-driven Z 51. Type 1936B (Mob) was the last design to which a destroyer actually came off the slip, although one light cruiser of the Spähkreuzer type, SPI, a 6,000-tonne scaled-up destroyer based on 1938 projections, was laid down in August 1941 at Germania Werft and work also advanced on the diesel-driven Z 51, a Type 1942 fleet torpedo boat originally intended to be T 43, Yard No 1109 at Deschimag.
All destroyers were built to the main frame/longitudinal bulkhead system using ST 52 steel and a lighter metal for the superstructure and innards. The first 22 were in commission in September 1939, but no further destroyers entered service for almost a year, by which time twelve of the original fleet had been sunk. At the end of World War II Germany had twelve destroyers left intact, plus one on the stocks and two—Z 44 and Z 45—launched but incomplete. The total number in commission during the war was 40, plus two foreign confiscations. Forty-eight torpedo-boats entered Kriegsmarine service, of which twelve survived intact. A large number were under construction in Baltic yards when the war ended.
Casting a jaundiced eye over the ships of the surface fleet, a senior German Admiralty official remarked after the war, ‘We Germans knew how to build outstanding freshwater ships.’ Naval building in Germany—in which destroyers were of course included—reached a stage in 1938 which led to a fresh strategy, set out in a memorandum by Fregattenkapitän Heye, Operations Officer of the Seekriegsleitung (Naval Warfare Office). Entitled ‘Die Seekriegführung gegen England und die sich daraus ergebenden Forderungen fiir die strategische Zielsetzung und den Aufbau der Kriegsmarine’, it was a decisive and important historical document which, read with the battle instructions of May 1939, set out naval policy in the event of war. The memorandum recognized that a ‘balanced’ Fleet was required, since, if Britain were the enemy, the German Navy would concentrate the weight of its offensive on the trade routes, thus attracting the might of the Royal Navy away from an expected blockade of Germany as had been imposed so effectively in the Great War. This thinking created the ‘Z Plan’.* Once drawn up, a Z Plan wargame was held, resulting in the following opinion delivered by Vizeadmiral Schniewind, SKL Chief of Staff:
‘1. Focus of German naval operations is on the oceans. The task here is to get our units on the trade routes. This objective serves domestic naval policy, primarily in the North Sea.
‘2. All possible theatres of war in the assumed scenario are closely linked. Successes and losses immediately affect the situation in another war area.
‘3. The war against the trade routes can be supported in Europe by the Luftwaffe focusing attacks against the enemy coasts.
‘4. Britain’s weakest point is tonnage, since supply will always be available. For Germany, the keeping open of the supply line will be more important than ships.
‘5. If Germany had naval bases on ocean coasts, the prospects for the success of an offensive naval policy against Britain/France would improve decisively. As long as we do not have our own bases, we have to resort to getting neutrals to collaborate and build up supply bases overseas.
‘6. Oceanic warfare requires the development of specific types of German naval unit and involving the mercantile marine in the aims of military policy.
‘7. I consider it certain that to develop the concept of oceanic warfare, linking all suitable means to this goal—to which I would add the heavy ships if necessary—would give us good prospects on the enemy trade routes. In the situation assumed in the wargame,* these prospects increase commensurate with the growth in naval forces which is not to be expected until 1943. I believe that in the then prevailing widespread nature of ocean warfare, operations promising success will present themselves for the deployment of the numerous smaller vessels: the theatre of possible localised conflict will not be limited to the North Sea, but to the high seas of all parts of the world.’
With this document Schniewind, in recognition of Germany’s naval inferiority but against his better judgement, set the course for the future. This fact was all the more obvious from the report of 20 January 1939, ‘Grundlagen und Probleme des Seekrieges, Aufgaben der Marine, Möglichkeit und operative Verwendung der Seekampfmittel’, which stated: ‘The idea of a “fleet in being” must be deleted for ever from German Navy manuals. It grew from a pessimistic foundation which took account only of purely intellectual, calculated factors. Pessimism weakens and is destructive of the fighting man. The history of all wars proves that, apart from certain material basics, the precondition for great success lies not so much in the human intellectual faculty as in the firm belief in one’s own strength of character, that is to say, in moral qualitities.’ In conclusion, the report predicted: ‘Confidence in the leadership of the State is so great, allowing no doubt to arise but that at the right time the present enormous difficulties of the political kind can be overcome in order to place the German Fleet numerically in the position to do justice to all such tasks as may fall to it.’ What a fallacy!
The advent of the Second World War took the German Navy aback and laid bare the weaknesses of the German Fleet. The Kriegsmarine was simply not in a position to take on its major opponent, the Royal Navy, in terms of either ships or trained personnel—particularly in the marine engineering branch. Destroyer operations in the first months of the war began with an extension of the Westwall or Siegfried Line, from the Dutch coast northwards to the Skagerrak, by means of a defensive mine barrage. Occasional anticontraband controls were carried out in the narrow coastal waters of the Skagerrak and Kattegat. The destroyer’s role was generally conceived to be escort, patrol and scouting duties in accordance with the description ‘workhorses of the Fleet’.
In November 1939 offensive minelaying operations began off the British coast. These required a high state of readiness of ship and machinery, for a relatively high speed had to be maintained despite the heavy cargo of mines, and this could only be guaranteed if the engine plant worked as it should. That this was achieved was attributable to a marked degree to the training of the NCOs and stokers and the preparedness of chief engineers to cut corners, knowing they could rely on the men under them. ‘Old hands know the ropes’ was the saying: in the German Navy everything depended on the few veterans in any team while the ‘new boys’ struggled to familiarise themselves with a confusing mass of piping, valves and stopcocks amidst the main and auxiliary machinery. Everything had to be absorbed in a short time—there was something new every day.
The Norwegian operation, although brilliantly handled, exposed the limits of German sea power. The occupation of France and the Low Countries brought valuable Channel bases, but these lost strategic significance once Operation ‘Seelöwe’, the proposed invasion of Britain, was given up. After a few early skirmishes in polar waters and a single successful Atlantic operation, the surviving battleships remained in port or fjord. Forays demanded an escort force which was needed more urgently elsewhere.
The idea of a substantial and enduring Luftwaffe involvement proved illusory. Russia and all the many other far-flung fronts proved that the shirt was too short. The Mediterranean theatre, the vast expanses of the Soviet Union and, the early collaboration between Britain and the United States asked too much of the Kriegsmarine in a naval strategic sense. Finally, all rested on the U-boat war. During 1941 the belligerent attitude of the neutral United States reduced its effectiveness, and with the American entry into the war the pendulum swung in favour of the Western powers. The ‘tonnage war’ could only be successful if the tonnage sunk exceeded the capacity to replace it, and that possibility no longer existed with the United States as an additional enemy.
By 1942, a Navy designed for economic warfare on the oceans had become a fleet of primarily medium and small active units, with the U-boats providing the main punch, and in January 1943 Hitler ordered the decommissioning of the big ships from light cruisers upwards. With this decision, Raeder, Naval C-in-C, stepped back. His successor, Dönitz, managed to have the instruction trimmed, but otherwise could do nothing. In June 1943 the Naval Building Programme was revised and naval armaments were tailored to the general war situation. Contracts could only be placed for vessels up to destroyer size, and the output of U-boats increased. Although the idea was good, this new programme stood in the shadow of the economic situation.
By the summer of 1943 the Kriegsmarine—with the exception of the U-boats—was for practical purrposes limited to coastal waters stretching from Biarritz to the Gulf of Finland, from Kiel to the White Sea. A striking factor throughout the war as a whole was the overall low destroyer availability for sea duty, at 40 per cent. On the 2,069 days between the outbreak of war and the end of April 1945, Z 15 Erich Steinbrinck was laid up under repair for 1,325 days, spending about 64 per cent of the war in the dockyard.*
Vizeadmiral Friedrich Ruge, after the war the first Inspector of the new Bundesmarine—and a widely respected historian—arrived at the following verdict: ‘The Second World War was won by those states which controlled the sea lanes. Even in the future these will play a decisive role … there is little argument [however] that our small fleet accomplished more than could reasonably have been expected of it.’
Naval Construction
German shipbuilders made no giant leaps forward with their destroyer designs. Studies involving theoretical calculations relating to weapons, machinery and equipment followed in the train of the military specifications. Once these were presented, there began the departmental struggle. The weapons specialists wanted a powerful armament with numerous barrels, superior to a supposed opponent they had in mind. Steadfastness, the ability to take punishment and the steaming range had to be good. This gave rise to discussions about the type and quality of the ship’s machinery. Finally, an overall decision was taken, the construction plans were drawn up and approved and the contract was placed with a yard.
So far as the first German destroyers—the Type 1934s—were concerned, it was recognised early on that these ships, built to the initial 1932 designs, did not measure up, and from the beginning they were spoken of as ‘reserve destroyers’. They were not very seaworthy, and they were generally unsuitable for deployment away from local waters because of their poor range—and seaworthiness and range were the very qualities which had been requested. Minor modifications to the bows of the Types 1934 and 1934A did little to alleviate the problems of poor sea-keeping and instability, and the Type 1936, which was a larger vessel fitted with an ‘Atlantic’ or ‘clipper’ bow, was not noticeably better. A larger main calibre weapon was introduced aboard the Type 1936A, and it was seen fit to mount two of these on the forecastle deck in a twin turret. This had a further adverse effect on stability and sea-keeping—and the ship had also to carry aloft the burden of several cumbersome radar aerials.
One is prompted to ask whether German naval architects had forgotten that a war was in progress. Design after design came pouring out of their offices. Wouldit not have been more sensible to have designed a relatively economic standard destroyer type suitable for mass production? The large German shipyards could be counted on the fingers of one hand—Germania Werft at Kiel and Blohm & Voss, Hamburg and Deschimag (AG Weser) at Bremen. Destroyer production was finally concentrated at the latter.
The war had taken a course in direct contrast to the flights of fancy exercised at the green table, and the reasons for the delay in naval building were listed in an OKM letter of 28 September 1940 as being (i) a lack of workers; (ii) a shortage of raw materials; (iii) problems in matérielsupply; (iv) new types of yard work being introduced, such as craft for Operation ‘Seelöwe’, the construction and fitting out of mine destructor vessels and increasing ship repairs; (v) transport difficulties; (vi) the suspension of work because of air raids, blackout etc; and (vii) the unusually fierce winter of 1939/40.
On 6 July 1940 Admiral Schniewind wrote that individual ship types exhibited a limited seaworthiness only and demanded ‘an improvement in design to guarantee trouble-free running and sea-keeping: therefore no high demands, but a high and reliable endurance of ship and machinery.’ This criticism included the destroyers. The individual destroyer classes of the Royal Navy, by comparison, had been built almost uniformly. From the ‘A’ class to the ‘H’ class, all had twin funnels, three triple-drum Admiralty boilers (wet steam with superheater) and two sets of turbines and could make about 36 knots; none had a standard displacement over 2,000 tons (on the contrary, all were well below this limit); and the gun calibre was 4.7in (12cm). With the ‘J’ class, the number of boilers was reduced to two, enabling one of the funnels to be dispensed with, creating more deck space for anti-aircraft weapons. Speed, size and performance remained unchanged. The ‘Tribal’ class, developed in the 1930s, were too expensive, had no advantages over the others and were not further developed. The 2,000-ton limit was first exceeded with the ‘Battle’ class, but the purpose was solely to increase bunkerage for greater range, the vessels having been planned for use in the Pacific. It must be added that Britain had a large number of yards that built for the Royal Navy, and, contrary to the German experience, their output was not affected by the initial enemy air attacks.
In the Reich it became increasingly difficult to fulfil orders. This was partly becvause of a shortage of skilled workers: in September 1940 the Naval Armaments Office, Department Wirtschaft V, reported a shortfall of 13,303 workers in the 65 most important supply industries and yards, and a further 7,050 vacancies were unfilled.
Not only had the bows of the new destroyers revealed deficiencies: the sterns were also unsatisfactory. A deflector wedge was added to the flat bottom, but it proved to be no solution: the design was simply bad. In comparison, the American Fletcher class destroyers, which had a similar stern form, proved totally successful despite increased weight demands arising from additional anti-aircraft weapons, depth charges, etc), and the same was true for other American, and British, destroyer classes. The typical stern shape of the German destroyer was chosen because substantial propulsion was needed for the heavy after section. It was also assumed that this would give a higher speed and improve sea-keeping at the bow. That a special bow design would be required in this case was unfortunately forgotten. It was rationalised that the ‘V form was better than a flat stern, but in practice it was very quick to ‘suck under’. The fitting of Totholz* and tunnelling above the propellers was only partially successful, for the stern now sat too high, creating too much turbulence and destroying the jet effect. Propellers are most efficient in a calm and steady waterflow, and much energy was lost in the turbulence, moreover, besides a stronger cavitation observed about the propeller blades, the rudder effect was also lessened.
Comparing the German destroyer types with the American Fletcher class side-on and through the frames, one observes how on the US type the draught begins to decrease from abaft No 3 gun. Screws and rudder work freely in a steady flow of water. On the US type the distance between No 5 gun and the end of the deck is shorter, and the Totholz stretches as far aft as the rear of No 5 gun. This design was so successful that it was used in cruiser construction up to and including the Alaskas. For a dry ship and better sea-keeping the forecastle had considerable sheer, which was evident to a lesser degree at the stern of larger types and later classes (see Hadeler, Friedman etc).
Weapons and Radar
The 12.7cm gun was the standard destroyer weapon and was located in five single gunhouses—No 1 gun on the foredeck with No 2 superfiring, No 3 gun on the after deck, and Nos 4 and 5 superfiring from mounts on the aft deck housing. The anti-aircraft {Flak) outfit was the standard 3.7cm and 2cm issue of the time, but this proved insufficient and during the course of the war numerous 3.7cm twin and 2cm quadruple mountings were embarked. As this extra weight topside added to the general instability and poor sea-keeping of the ships, one of the 12.7cm or 15cm main turrets was unshipped in compensation.
A wartime measure beginning with new Type 1936A destroyers was an increase in the main calibre to 15cm (5.9in). However, as by April 1940 Germany had available only four light cruisers—Emden, Köln, Leipzig and Nürnberg, the last three being such poor sea boats that they were not permitted beyond coastal waters in bad weather—the thinking behind the larger calibre was almost certainly to ‘cruiserise’ these later destroyers to the extent that, if necessary, they could take on British light cruisers in battle. The straight changeover of calibre retaining the designed single-gunhouse layout would not have caused problems in itself, but it was then considered—against the stated opinion of sea-going destroyer officers—to be a good idea to increase the number of guns on the first three Type 1936A ships (Z 23 to Z 25) from four 15cm in single gunhouses to five 15cm, three in single gunhouses aft and two in a twin turret on the forecastle deck. Inevitably this extra weight forward brought more sea-keeping problems, stability was impaired and a speed restriction had to be imposed during inclement weather.
The later projected designs returned to the 12.7cm calibre. Other projects included the 12.8cm multipurpose KM 41 gun in a twin turret, for use against aircraft as well as surface targets, which would, had it ever been developed, have led to a reduction in numbers of the less effective 3.7cm weapon on board ship; a 45kg salvo was, theoretically, possible every five seconds. The other weapon was the fully automatic, air-cooled, gas-pressure-loaded 5.5cm Flakgerät 58, the first designs of which from Naval Ordnance Office sources bear the date 9 October 1944. Several prototypes were completed and, according to unconfirmed reports, were tested aboard a destroyer. Rate of fire was 120-150 rounds per minute, and single-round firing was also possible.
At the end of the 1930s Germany led the field in radar. There were numerous developments, and many well-known scientists and companies were involved in pushing ahead with the technology. They found little approval from the highest levels, however, and shortly after the outbreak of war Hitler ordered that all investigation in the field of radar should be halted. Before 1938 the Luftwaffe leadership had come down heavily against the usefulness of researching radar, and it was not until well into the war that British progress was discovered—thanks to a set which used the lower-centimetre wavelengths being found in the innards of a crashed bomber; this explains the difference in size between the small British antennas and the gigantic steel ‘mattresses’ carried aboard German warships.
Although German firms and scientists had continued their work in secret despite the prohibition, even now they still ran up against absolute official disinterest and a lack of coordination between not only the various fighting arms (the U-boat arm being the most cooperative) but also the multitudinous experimenters in radar development—there were more than a thousand different models occasionally available for inspection—most of whom, intent on profiting from their research, continued their own projects in circumstances of the most exaggerated secrecy. That there was a war on, and that the need for co-operation was therefore paramount, was not understood.
Machinery
During the design and planning stage of the destroyers the question of the right machinery became acute. The ‘pocket battleships’ had broken new ground with the introduction of pure diesel drive, but the majority of the other new vessels had made do with the usual (if somewhat improved) wet-steam plant. The exceptions were the light cruisers Leipzig and Nürnberg, and it is incomprehensible why they should have been fitted with diesels to complement an out-of-date (respecting the steam pressure and temperature) wet-steam plant.
The plans for the first four destroyers were completed early in 1932 to specifications for a high-pressure/hot-steam installation with turbines, two shafts and a 12.7cm armament. Demands for a heavier anti-aircraft battery and more torpedo tubes, a higher speed, a greater range and better engine output led to a greater displacement. Because of the demand for high output, diesels were not considered: at that time insufficient data was available respecting the performance of diesels aboard the large warships which had them (the pocket battleship Deutschland and the gunnery training ship Bremse). Accordingly, the Wagner High Pressure Company received an order for a 26,000hp turbine plant as a project, the size of the output forcing the greater displacement. Violent controversy ensued between ‘K’ (the Konstruktionsamt, or Office of Naval Architecture) and Tng’ (the military marine engineering department) on the question of steam pressure and temperature: the architects were cautious whereas the naval engineers wanted to go the whole hog. ‘K’ was also uninterested in a further development of the proven Wagner boiler with its natural circulation and expected much of other boiler types—Benson, La Mont and Velox.
A supernumerary Benson boiler had been installed in 1930 aboard the freighter Uckermark for experimental purposes; it had a steam pressure of 225 atmospheres and a temperature of 450°C. The plant included a number of innovations and proved successful. The point here is that a merchant ship at sea maintains generally much the same engine output and speed from leaving one port to arriving at the next; there is hardly any change in the pressure. In a warship, on the other hand, one expects constant changes in engine speed as the result of proceeding in formation, in manoeuvring and in the daily training schedule, and the engine room has to satisfy the requirement. Because of this, great demands are made of the machinery, particularly the boilers. Taken overall, the question of boilers was the decisive consideration leading to the selection of high-pressure, hot steam: the guarantee of performance was paramount.
The gunnery training ship Brummer, commissioned in 1936, had trouble-free Wagner boilers but her auxiliary machinery proved very prone to breakdown. To save space and weight these were mostly driven by small turbines or had electrical motors (the feed for which came from the turbo-generators), which were thoroughly uneconomical because of the constant demand for steam to keep them running. This meant that steam had to be maintained permanently in some form of boiler, and this increased the ship’s fuel consumption. The fuel consumption of wet-steam machinery was 0.6-0.7kg/shp, for high-pressure, hotsteam machinery 0.3-0.4kg/shp. With diesels the figure was 0.25kg/shp. A compromise was finally reached in which some of the destroyers had Wagner and the others Benson boilers. The Wagner was a water-tube boiler with natural water circulation; the Benson had forced circulation, wherein the feedwater is forced through the boiler tubes, where it is superheated and evaporated. The system was deal for a warship, but the weakness lay in the ability to manoeuvre—which led later to the addition of a steam collector.
To resolve the boiler problem it was decided to test out the three newer types—the Velox on a minesweeper and the similar La Mont system aboard the old battleship Hessen, while Blohm & Voss would report on the Benson. The difficulties the early destroyers had experienced with the Wagner were documented for comparison. Their future wartime use was questionable, but at the time nobody was thinking of war. The main advantage was recognised as being high engine output in the smallest area (about 10kg/shp). Diesels had not achieved this at the time, the value aboard the pocket battleships being much greater. The high-pressure, hot-steam system seemed ideal for destroyers in view of their assumed role mainly in coastal waters, for (i) economic use of space, (ii) tolerance of pressure changes, (iii) rapid readiness for use, (iv) resistance to hits striking the ship, (v) reliability, (vi) low noise output and (vii) resistance to shock. In the event, however, the impetuous pace of development brought serious drawbacks. Personnel at all levels lacked a well-founded theoretical knowledge of the machinery and the expertise to master it. The new boilers required the maximum technical understanding of procedures, for the automatic regulating installations did not necessarily respond appropriately to sudden increases in output, which then required manual intervention. The new system had a mass of extra piping and armatures and was very susceptible to breakdown in the vacuum (condenser parts), often resulting in salting up. Oil and lubricant supply piping was also frequently affected. Fuel consumption was not drastically diminished, and the materials question began at high temperature.
Another of the really important demands of the new destroyer that was never fulfilled was the yearned-for great range. In the original specifications, 5,000–6,000nm at 20 knots and 7,000nm at 17 knots had been desired, but in practice the Type 1934 made 3,100nm at 19 knots and only a hundred more at 15. An SKL memorandum of February 1941 observed: ‘The few ships available would have been able to undertake much more had they measured up to specification and had they been deployed accordingly.’ This referred to the high susceptibility to breakdown of the new hot-steam engine plant, which, by reason of its complicated design and inaccessibility, required a long period in dock for even the minor types of repair. The memorandum also complained about limited range and poor sea-keeping, which brought into question whether the vessels were actually battleworthy; for future new con structionit was necessary to lay down clearly that the steam pressure and temperature had to be reduced. In general it was a strident criticism of the ships and their machinery.
This criticism was naturally not without its influence on shipboard officers. Many chief engineers set out deliberately to spare boilers and tubes by ‘working measures’ involving lower boiler pressures. Commanders were usually prepared to connive with the chief engineer, even if it involved a breach of regulations. In the shipyard while under repair, destroyers were often given structural and other ‘improvements’ without the knowledge of the powers above. This explains how Z 4 Richard Beitzen, one of the first four new-build German destroyers, could enter the yards in May 1943 for a refit having remained operational for 524 days and steaming 32,000 miles since the previous visit.
Compared to other systems, high-pressure/hotsteam had indisputable advantages for turbine drive, particularly the reduction in time needed to raise steam and an improvement in manoeuvrability, both of which matched expectations (the Benson boiler proving superior in this respect). In the Battle of the Bristol Channel on 17 October 1940 involving the German destroyers Hans Lody, Karl Galster, Erich Steinbrinck and Friedrich Ihn and a mixed force of British cruisers and destroyers, an engine room NCO aboard one of the Type 1934As had the turbines running full out only nine minutes after firing two cold boilers. The system required numerous auxiliary equipment, and this additional demand for steam brought so many disadvantages in its train that the military value of the system as a whole was considered questionable.
The possibility of a basic improvement preoccupied many veteran sea-going chief engineers, one of whom was Kapitänleutnant (Ing) lilies; he had been a member of the destroyer construction permanent instruction staff, was involved in the sea trials of the first destroyers and had been chief engineer of Z 2 Georg Thiele at Narvik. He took a keen interest in the problem of steam consumption, particularly that relating to auxiliary plant, and his deliberations resulted in the development of a system of control comparable to the accelerator pedal of a motor car combined with electric drive for all auxiliary machinery. This created an altogether simpler system of construction, better reliability, easier handling and a reduction in repair time and thus in the queue for repair. He amassed additional data during the workup of the battleship Tirpitz as a member of the Warship Testing Branch. In order to force through his ideas, he made contact with household names in industry and the universities to clarify points of doubt and finally prepared a memorandum which the Warship Testing Branch (EKK) received in January 1942, from where it was passed upwards with a positive recommendation to the OKM Warship Construction Headquarters. He also gave a copy to a functionary involved in military economics, from which source Speer’s Ministry for Armaments and Munitions received it. When this came to the attention of the EKK, they demanded the return of the paper and lilies was reprimanded for passing an official document to an unauthorised recipient. Unabashed, he compiled another paper, ‘Entwurf einer Zerstörerantriebsanlage’ (Design for a Destroyer Propulsion System), and submitted it to EKK. The functionary in military economics also came into possession of a copy by unknown means and, relying on a new Führerbefehl, forwarded the memorandum to a Hamburg shipyard owner.* This was too much for the OKM, however, and lilies was hauled before Admiral Raeder and sentenced to fourteen days’ confinement to quarters for breach of confidence. lilies’ second paper came to light at OKM through the normal channels in July 1942 while the first memorandum remained a thorn of contention between the ship machinery department (KIV) and the naval designers (KII).
As interest elsewhere grew in lilies’ proposal, he was invited to attend a conference at the end of 1942, as a result of which it was decided that ‘for the clarification of hitherto uncertain questions the firm of Schichau will receive a contract to design a fleet torpedo boat incorporating the suggestions of Kapitänleutnant Illies. The results of this investigation will be made known at the appropriate time.’
Following the resignation of Admiral Raeder in January 1943, lilies was transferred to the Schichau yard, where work was beginning on the I-S Anlage project. All naval armament schemes received a boost on 22 July 1943 when they came under the umbrella of the new Shipbuilding Commission at the Speer Ministry. The I-S system was first tested on 8 January 1944 and listed for installation aboard the new Type 44 torpedo boat. None of these was completed by the war’s end, however. The Schichau shipyard was taken over by the Soviets in January 1945: what documents were confiscated there is not known.
Diesel Drive for Destroyers
The economy of a steam engine—compared to diesel plant—depends not so much on pressure as on the temperature of the steam entering the turbines. The machinery simply transforms heat into mechanical energy, and the hotter the steam the more the energy produced. The temperature of so-called saturated steam—that is, steam before superheating, is about 200°C at 15atms, 235°C at 30atms and 340°C at 150atms, and the critical point is reached at 225atms with a temperature of 374°C. Thus the temperature rises much more slowly than the pressure—in other words, only a higher temperature can bring about an increase in output, by superheating. At this stage the problem of materials comes into play—steel alloys must be used—and the expected fuel saving (at least, on a warship) becomes debatable owing to numerous auxiliary engines all consuming steam. High-pressure/hot-steam has significant advantages—smaller boilers, fewer personnel, clean fuel—but its disadvantages are the high temperatures. Steam plant of this kind can only be run with efficient regulating machinery, and this has to be supervised, which requires more personnel. There is also an intense demand for feedwater.
The I-S Engine Plant: Scheme of the Testbed Layout
Key: A Main boiler. B Main turbine installation. C Main condenser. D Regulator box. E Condenser pumps. F Main distributor. G Condenser re-cooler. H Main feedwater pump. I Feedwater pre-heater. K Boiler supercharger. L Atomiser supercharger. M Steam pressure/air mixture boiler regulator. N Air mixture/heating oil boiler regulator. O Feedwater/steam differential pressure boiler regulator. P Regulator oil pump. Q Heating oil pump. R Turbine oil pump. S Main cooling pump. T Turbo-generator. U Steam suppressor. V Auxiliary condenser. W Auxiliary boiler. X Turbine control stand. (From files of F. Schichau AG, Elbing 1944: Bröckow, Geschichte des deutschen Marine-Ingenieur-Korps)
The diesel motor needs none of this regulating equipment and therefore demands fewer personnel. It is also instantly ready. A diesel ship has great range, but it requires fuel of a better quality fuel, which is more expensive. In the period between 1928 and 1935 MAN Augsburg built a light, double-acting, two-stroke diesel motor to German Navy specifications which had proved satisfactory aboard ship after initial teething problems, and it was the exaggeration of these problems by the steam lobby that led to the abandonment of diesel drive for large warships in favour of high-pressure/hot-steam for the critical rebuilding period from 1935 onwards.
From about 1938 there was a revival of Kriegsmarine interest in diesel-driven warships, but with the advent of hostilities it was all placed in abeyance and contracts were subsequently placed for only one ship, a Type 1942 experimental destroyer, Z 51. The order for six diesels was placed with MAN at the beginning of 1943, and four had been built by the war’s end. Test work on the prototypes was abandoned for lack of fuel in February 1945. The 24-cylinder (2×l2), 320mm-bore, 440mm-stroke motor, designated V12 Z32/44, was a V-form, fast-running, double action, two-stroke motor of welded steel construction. Maximum revolutions were 600 per min, piston speed 8.8ms, maximum output was 12,000hp, medium effective pressure 5.52kg/cm2 and fuel consumption at maximum demand 185g/hp/hr. The dry weight of the engine, including auxiliary machinery but excluding the oil cooler, was 67 tonnes.
Layout of main diesels aboard Z 51 (1942).
If the work on Z 51 had been seen through to completion, the ship would have represented a great stride forward for the German Navy. There was, behind the design, a marked ‘oceanic’ thinking, caused by the dearth of light cruisers, for with diesel drive this type of destroyer would have had a range to equal not only that of the the pocket battleships but also of the Uboats.*
The monthly Wehrtechnischen Monatsheft, in its 4/56 issue, concluded on the eternal controversy between high-pressure/hot-steam and diesels: ‘It was the tragedy of German warship construction that faith [in diesels] was lost during the battle against high-pressure/hot-steam, and was accordingly renounced by the military side. It was a further tragedy that this struggle occurred at a time when the Naval Architect’s Office had a technical chief not up to the high demands of the post. (And it must be noted that the choice of the person to fill the post was made not on the recommendations of the engineers, but of the military.)
The MAN V-form V12Z 32/44 diesel at the firm’s Historical Museum, now located in the Auto und Technik Museum, Sinsheim, Kraichgau. This was one of the four motors built by MAN on contract for the Type 1942 destroyer Z 51.
Stern section and machinery of destroyer Z51 (1942). (MAN Archive).
The Spähkreuzer Programme
Mention should be made here of the twenty-two 5,000 tonne small scouting cruisers known as Spähkreuzer, envisaged under the ‘Z Plan’. Orders were placed with Germania Werft for the first three in February 1941. SP 1 (ex Z 40) was laid down as Yard No 642 on 20 August 1941 and Nos 643 and 644 were allocated for SP 2 (ex Z 41) and SP 3 (ex Z 42). The ship was basically a scaled-up destroyer to a Blohn & Voss design based on variations of the projected Type 1938 Type. The entire Spähkreuzer programme was abandoned in late 1941, although the six engine plants remained on order in December. Displacement: 4,589 tons standard, 5,900 tons full load. Dimensions: 152.2m×14.62m×4.66. Seventeen watertight compartments. Machinery: turbines (77,500shp) plus diesels (14,500hp). Speed 35.5 knots (turbines). Bunkerage 820 tonnes max. Range 8,000nm at 17 knots. Five ship’s boats. Complement 18 officers and 520 men.
In this general connection it may also be of interest to remark that the German Navy showed no interest in a Brown Bovery & Cie gas turbine and diesel mixed system for destroyers offered in 1939. The Type 1940 destroyer, which got no further than the drawing board, was designed to mount sixteen diesels providing 60,000hp for a speed of 40 knots. Range would have been 10,500nm at 19 knots.
* The author lists the following Imperial Navy vessels retained as ‘destroyers’: V 185, V 190 and G 196 (built 1910–11), V 2, V 3 and V 5 (1911), G 7, G 8, G 10 and G 11 (1911–12) and S 18 and S 23 (1912–13), plus V 1 and V 6 (1912) in reserve—a flotilla of twelve plus two reserves. Retained as ‘torpedo boats’ were S 139, S 141, S 143, S 146, S 148, S 149, V 151, V 153 and V 154 (built 1906-07), V 156, V 157 and V 158 (1908) and S 168 (1911) plus S 144, V 152 and V 155 (190-08) and G 175 (1910) in reserve. This is thirteen plus four reserves and one assumes an erroneous listing here of a ‘destroyer’ in reserve—probably T 168 or T 175, the two newest ships. Tr.
* See Conclusions for the make-up of the Z Plan.
* At the time the wargame was held, nobody was seriously thinking of war, and certainly not against Britain. Wargames of all types, including military manoeuvres, are commonplace and belong to the normal military programme of all nations. The situations assumed are theoretical, as are the resulting plans and counter-measures. In earnest they count as underlying preparation.
* These periods are listed in this destroyer’s career section, in order to highlight the problems involved. Also included are the number of missions sailed and casualties sustained. A ‘mission’ was any voyage from port to port, an period escort duty, a patrol, a minelaying operation or an engagement with the enemy. Points were awarded for involvement in an action and were the basis for the award of the Destroyer Badge and Iron Cross First and Second Classes. The leading five destroyers for missions sailed were Z20 Karl Galster—131; Z 4 Richard Beitzen—104, Z 14 Friedrich Ihn—89; Z 6 Theodor Riedel—66; and Z 25—also 66. All had a negligible casualty list.
* The Totholz is that part of the hull forward and aft below the waterline which contributes to the broadside or lateral plan while having a negligible effect on displacement. The term originates from the time when wooden full-rigged ships required a large lateral plan for sailing with the wind on the beam, the additional resistance being provided by heavy board (hence ‘deadwood’), which took up no interior space.
* According to the Führer directive, all inventions and improvements in the weapons and military-economy field could be sent by any German to a special field post-office box within the Speer Ministry.
* Z 51 was laid down at Deschimag Bremen on 25 November 1942, Yard No 1109. Displacement: 2,041 tons standard, 2,328 tons designed, 2720 tons full load. Dimensions: 114.3m×11m×4.37m (max); freeboard 6.5m. Armament: 4×12.7cm in single gunhouses, two forward and two aft; 8×3.7cm and 12×2cm AA; 2×3 torpedo tubes; up to 50 mines. Fifteen watertight compartments. Machinery: six diesels developing 57,120hp; 3 shafts; 3 rudders. Speed 36 knots. Bunkerage 553 tonnes max. Range 5,200nm at 19 knots (much greater at lower cruising speeds).