The Naval Campaign for Norway and Denmark 1940
A Case Study in Operational Planning
Commander Ken Hansen and Dr. Chris Madsen
Canadian Forces College
The German invasion of Norway and Denmark in April 1940 hinged upon the projection of naval, land, and air power within a defined geographical area, at some distance from established operating naval bases and airfields. The Kriegsmarine, a small and only recently rearmed navy, challenged the Royal Navy, the world’s pre-eminent naval force. Throughout the naval campaign, command of the sea in the littoral waters off Norway and Denmark remained contested or in dispute. The Germans used deception, surprise, and boldness to facilitate the movement of their troops and equipment to strategic points along the Norwegian coastline, as they did not have the naval power to ensure the protection of their transport vessels. The entire operation involved the acceptance of risk for demonstrable operational and strategic gain. Although the Royal Navy struck back and inflicted considerable, arguably irreplaceable, losses on the Kriegsmarine, it proved powerless to prevent the build-up of German combat power ashore and the growing domination of the Luftwaffe over adjacent maritime areas. The decision to withdraw British naval forces in the face of such threats ultimately sealed the fate of Norway and Denmark. Through this victory, the Germans were able to significantly enlarge the frontage available to their naval and air forces. Norway became a major base of operations for later naval actions in the Atlantic and Arctic Oceans.
Although the campaign for Norway and Denmark represents an excellent example of joint operations and manoeuvre warfare, this case study focuses predominantly on the naval component of the operational campaign from a planning and conduct perspective. The aim is to solidify a better understanding of basic operational-level concepts in the maritime context through careful analysis and assessment of the Kriegsmarine’s part in the planned German offensive and the Royal Navy’s response to it. To accomplish this, a number of key questions must be answered. What were the key elements of campaign design in naval and joint planning before and during the German invasion of Norway and Denmark? How effectively did individual naval officers and respective naval staffs interact with higher strategic authorities and the other services? Were theatre-level imperatives, such as centre of gravity, positions, bases of operations, physical objectives, decisive points, lines of operation, and sequencing, correctly deduced and applied? How important were enabling operations, in particular intelligence and logistics?
Necessary historical background can be found within this case study and the additional sources in the selected bibliography listed at the end. This material provides a medium to highlight similar opportunities, challenges, and problems that a staff officer or commander might face in planning and conducting such a naval campaign today. The littoral aspect of the naval operations off Norway and Denmark, with their significant air and submarine threats, has obvious applicability for Western navies that are increasingly thinking about green water operations. History, as the noted British historian E.H. Carr once described, is a continual interaction between the present and the past. Syndicate members, therefore, should be guided by current operational-level considerations and not get too drawn into historical detail, no matter how interesting it might be.
Scandinavia’s Strategic Significance to Germany
Germany was the hostage of her geography. Both world wars largely concerned the aspirations of the largest and most powerful country in Central Europe to gain more territory, greater access to resources, and increased security at the expense of its neighbours. Two opposing views prevailed: those who believed that Germany was inherently a land power and should maintain a strong army; and those, particularly influential German merchants and the middle-class navy, who saw the future in economic trade and imperial possessions on a wider global scale. The former brought Germany directly up against France and Russia, whereas the latter made tensions with Great Britain almost inevitable. The First World War left the matter unsettled. In that conflict, Norway, Denmark, and other Scandinavian countries managed to maintain their neutrality and stay out of the general fighting, although the large Norwegian merchant fleet suffered terribly once unrestricted submarine warfare started in earnest. The vulnerability of Scandinavian countries to German military power was offset only by the desire of the Kaiser and the German general staff not to give the Triple Entente a pretext to open another front in the north. Thus, strategic necessity delivered a modicum of uneasy security until the end of the war that continued into the interwar period. With the possible exception of Sweden, Scandinavians allowed their defence establishments to run down on the assumption that resistance to any German arms would be futile. When Adolf Hitler and the Nazi Party ascended to power on a definite programme of restored national strength and rearmament, the prospect of an expansionist and militarily aggressive Germany again worried many people on that country’s doorstep. Hitler publicly promised peace in return for land and re-sources. In secret, he planned for war.
The unique geographic position of Denmark and Norway attracted special attention within the Kriegsmarine. The Royal Navy’s blockade of the North Sea during the First World War had largely confined the German High Seas Fleet to port. There were exceptions: the major sortie resulting in the Battle of Jutland in 1916 and, of course, the ruthless yet effective use of U-boats in the latter part of the war. Germany, with its short coastline, split between the North and Baltic Seas, lacked bases from which to challenge the preponderant British naval strength. The Royal Navy could easily concentrate sufficient naval forces to bottle up German surface units, while it maintained unfettered access for the United Kingdom to overseas and continental destinations. The Ger-man navy was left in “a dead angle in a dead sea,” as described by Admiral Wolfgang Wegener in his 1929 book The Sea Strategy of the World War. Wegener’s proffered solution to Germany’s strategic dilemma was occupation of Norway and the development of naval bases there.
Wegener was a Mahanian fleet theorist and advocated the navy’s priority over the army. He argued in favour of a fleet large enough to defeat the Royal Navy and the occupation of Norway as a consequence of this great victory. For Wegener, territorial expansion came as a natural consequence of victory at sea. The commander-in-chief of the Reichsmarine and later Kriegsmarine, Grand-Admiral Erich Raeder, strongly disagreed on most things with Wegener, who was a class-mate and former close personal friend. He understood that the navy was the junior service to the army and, with the rise of Herman Goering, Raeder also accepted an inferior status to the Luftwaffe. Admiral Raeder did not believe that the Royal Navy could be challenged at sea so long as the primary defence objectives for Germany’s armed forces lay within continental Europe. His initial inclination towards the Scandinavian countries was to advocate for their continued neutrality. Instead of fighting to obtain naval bases in Norway, he negotiated an agreement with Russia for the use of a secluded northern anchorage as an alternate to break out of Wegener’s ‘dead angle’. Raeder’s naval strategy was devised around fast ships of high quality that could outfight most opponents and outrun those that they could not openly confront. The Anglo-German Naval Agreement of 1935 gave Germany the right to build up to 35 per cent of Britain’s total tonnage in all classes of warships, except submarines, which were allowed to total 45 per cent of the RN’s fleet. In late 1937, when Hitler unexpectedly announced that Britain was, in fact, a potential enemy, a larger and more balanced fleet was projected under Raeder’s so-called “Z” Plan. This fleet, while still relying heavily on qualitative superiority to offset numerical inferiority, would have been strong enough to challenge the Royal Navy for local control in the North and Norwegian Seas, especially if portions of the British fleet were engaged elsewhere. Still, the German naval staff worked under the assumption that war against Great Britain would not be pursued until at least 1943 or 1944, an assurance reaffirmed by Hitler to Raeder on several occasions. The unexpected early outbreak of war in September 1939, when Great Britain and France refused to back down in the face of Hitler’s demands over Poland, overturned Raeder’s tidy plans for the Kriegsmarine’s orderly development.
Denmark and Norway, as expected, remained neutral in the early stages of the war. However, their position astride the passage into the Baltic Sea and dominating the North Sea meant that they could not be left out of German naval considerations. Earlier, during the Russo-Finnish ‘Winter War’, strong popular sentiment for British intervention on the side of Finland had led to contingency plans for landing an international intervention force at Narvik and transporting it overland to Finland through Sweden. British withdrawal from the plan led to the collapse of a proposed Scandinavian defensive alliance. However, the German military took notice of the British focus on Narvik for another very critical reason. Germany was dependent upon iron ore imports from Sweden for over a third of its total industrial production. Moreover, the high-quality Swedish ore was crucial for the majority of its war effort. While the summer months allowed the ore to be shipped across the Baltic Sea, in winter the bulk of this strategic commodity, amounting to approximately 9 million tonnes per year, travelled by rail to the northern Norwegian port of Narvik and thence by merchant vessel down the sheltered Inner Leads through Norwegian territorial waters. The Germans argued that such passage was legal under their interpretation of international law, although the British opinion differed. The neutral Norwegians were caught between the conflicting demands of the two belligerents to either carry on as usual or stop the traffic altogether. Diffident Norwegian adherence to the letter of international law left neither side satisfied. In the early days of the war, the Royal Navy regularly sallied into Norwegian waters to lay minefields that forced ships into international waters where they could be stopped for visit, search, and seizure. The Germans protested vehemently against such flagrant abuse of territorial waters, but to no avail. The low point came on 16 February 1940 when a force of British destroyers boarded the Altmark, a German naval auxiliary making its way back to Germany through Norwegian territorial waters, and released some three hundred British prisoners taken captive by the armoured ship Graf Spee.
The British action was highly questionable from a legal perspective, but it invited widespread praise back in Great Britain and equal condemnation from Hitler. More seriously for the Germans, their vital supply of Swedish iron ore was insecure and could not be escorted with the relatively meagre naval forces at their disposal. Moreover, Admiral Raeder was apprised of intelligence re-ports that indicated Britain was preparing plans for the landing of a French-British force in northern Norway. Britain was aware both of Germany’s vital dependence on Swedish iron ore, the loss of which would mean rapid collapse of its armaments industry, and of the expansionist doctrine espoused by Admiral Wegener. A move into Norway would both forestall a very dangerous German initiative and cripple Germany’s wartime industrial capacity.
The Nazi leader turned to Vidkun Quisling, a former Norwegian naval officer and head of Norway’s small fascist Nasjonal Samling party. This Nordic fascist blood-brother promised to under-mine the Norwegian monarchy and work from within to establish a political regime in Norway more friendly towards German interests. Despite these internal political overtures to support the German position, further violation of Norwegian territoriality by the Western Allies seemed a distinct possibility and a military intervention had to be contemplated. The British and French had, indeed, progressed their plans to land troops, whether invited or not, in northern Norway. Little wonder, then, that Hitler and senior members of the German armed forces concluded that neutrality on the part of Norway counted almost for nothing and that imminent Allied actions in Norway must be forestalled. Directions were given to accelerate planning and preparations for Operation “Weserübung,” the projected invasion of Denmark and Norway.
By the time Hitler decided to disregard Norwegian neutrality, contingency plans for the occupation of Denmark and Norway were already well under way. As early as October 1939, Raeder had suggested to Hitler that plans to bring Norway under German control should be prepared. The admiral pursued informal talks with Quisling through Alfred Rosenberg in the German foreign ministry and personally introduced the Norwegian fascist leader to Hitler. On the basis of this interview, Hitler directed that a small group of staff officers be established to consider planning for a military operation against Norway, and he gave the responsibility to the Oberkomman-do der Wehrmacht (OKW), a relatively new joint staff with limited jurisdiction in the Western European operational area. The chief of the OKW was Colonel-General Wilhelm Keitel, a thoroughly political general, although the bulk of actual work came under the direction of the modest and meticulous Major-General Alfred Jodl, Nazi Germany’s staff planner extraordinaire. Planning for upcoming operations against France and the Low Countries, code-named “Case Yellow,” was in full swing, and the OKW considered prospective action against Norway and Denmark only in terms of priority and previously uncommitted forces. Since the Kriegsmarine was hardly involved in the largely land-based offensive in the West, Raeder and his naval staff, the Seekriegs-leitung (SKL), assumed a disproportionate share of influence in the concurrent joint planning against Norway.
Not surprisingly, staff planners looked toward a maritime solution to the difficult problem of subduing a country with a long, rugged coastline and lacking well-developed communication and transportation networks. On 10 January 1940, the OKW put forward Studie Nord, a very preliminary plan dealing with Norway. It assessed the likelihood of a British landing in Norway as high and outlined in rough terms the scale of assault and follow-on forces required. At Raeder’s direction, SKL further refined Studie Nord to include seaborne descents on all Norway’s major coastal cities and towns in two waves, the first by warship and the second, with accompanying logistic support and heavier artillery, by merchant vessel. The Germans counted on the absence of alerted opposing naval forces and safe return of participating warships before the British appreciated fully that an invasion was actually taking place. Surprise represented the foremost principle and without it, the Kriegsmarine faced a recognizable danger from fleet units of the Royal Navy.
Further refinement of the preliminary Studie Nord was worked into a broad operational plan un-der OKW auspices over the next few weeks. Hitler had not yet made up his mind over Scandina-via, but he directed Keitel and Raeder to continue study and work in the event of an unforeseen contingency, namely British intervention in northern Norway. In early February, Captain Theodor Kranke, commanding officer of the armoured ship ADMIRAL SCHEER, was seconded for special duty to oversee the efforts of a dedicated planning group within the OKW’s operations branch. Again, naval officers remained strongly represented on the planning staff, although dele-gates from the other armed services were invited to participate. It was about this time that the code name “Weserübung” first began to be used. Once completed, Kranke’s plan followed many of the same assumptions and conclusions of the earlier Studie Nord. The key to a successful invasion was the quick and simultaneous seizure of the main population centres at Oslo, Kristiansand, Arendal, Stavanger, Bergen, Trondheim, and Narvik from the sea, thereby decapitating potential Norwegian resistance and denying the British forward operating bases. The initial “Weserübung” planning also gave the Luftwaffe a far larger role in the actual delivery of some assault forces and protection of the naval forces during the landings and later withdrawal of warships back to the safety of German waters. Reconnaissance and control of the littoral waters off Norway was to be provided by air forces flying from existing bases in Germany and captured airfields in Denmark and southern Norway. Kranke and his planners realized that much depended upon weather, but they believed that, given sufficient air cover, the Royal Navy could be kept at a safe distance while the landings and their subsequent reinforcement proceeded unmolested. It was a risky pro-position, but one that Kranke, Raeder, and the Kriegsmarine willingly accepted. The ALTMARK affair and the perceived unwillingness of the Norwegians to counter British heavy-handedness gave the German planning for a military and naval operation an added impetus.
Hitler issued his formal directive for “Weserübung” on 1 March 1940. Although no exact date was set for implementation, the preamble and specific strategic guidance to the operational commands made clear that an invasion of Norway was not only likely, but imminent. Hitler ordered that preparations were to be made to go at four days’ notice, anytime after 10 March. General Nicolaus von Falkenhorst, commanding the XXI Army Corps, which included specially trained mountain troops, was placed in command directly under Hitler for overall conduct of operations, while the commanders-in-chief of the Kriegsmarine and Luftwaffe retained respective control over their forces employed in theatre. Falkenhorst included occupation of Denmark as a necessary prerequisite to the assault on Norway. Consequently, the operation was divided into two distinct parts: “Weserübung South” which directed troops to cross the Danish frontier and move up the Jutland peninsula as far as Skagen; and “Weserübung North” which simply directed “the surprise occupation of important places on the coast from the sea and landing by the air.” The Kriegsmarine was given primary responsibility for seaborne assault, reinforcement, and supply.
Naval planners were not especially sanguine about the prospects that the Kriegsmarine faced. Long discussions on Hitler’s directive and the naval contribution acknowledged: “The operation actually goes against all the precepts of naval warfare. Naval supremacy in the intended area of operations definitely lies in enemy hands because of the far superior British Fleet. In spite of this, the Naval Staff is convinced — given surprise — that it will be possible without very great difficulties to take the troops across with naval forces, penetrate into the fjords, land in Norwegian ports and take possession of the harbours and fortifications.” Safe return of German warships, however, in a sea contested by the Royal Navy was another matter, especially for those coming from the northernmost ports. The SKL issued its first directive to naval groups and commanding admirals on 7 March. Battle cruisers, cruisers, and destroyers were not to linger close to shore for any more time than necessary once refuelled, although Hitler and Falkenhorst insisted that the presence of warships was needed to bolster German land troops. Field Marshall Hermann Goering’s offhand comment that the Luftwaffe would provide all the necessary protection was hardly reassuring. A hasty retreat after disembarking the troops was still seen as the best option to preserve the surface units and, in turn, the future operational capabilities of the Kriegsmarine. As an added precaution, submarines were directed to take up station off Narvik, Trondheim, and the north coast of Scotland. Indeed, the naval staff postponed all other operations, including the sending of U-boats into the Atlantic, and held available naval forces ready for the Norway assignment. Icy conditions delayed movement of ships from the Baltic, but the extra time allowed completion of repairs to engines and boilers on several destroyers, of which 14 were serviceable by 25 March. At an afternoon meeting in the Reich Chancellery on 1 April, Hitler met personally with the commanding admirals as well as the land force and sea force commanders of the individual task groups, demanding “most exhaustive reports from all the officers and [he] asked many questions. In con-clusion he stated his complete agreement with the preparation made and expressed his thanks for the recognition of the work performed during the preparations.” The next day, he ordered “Weserübung” to take place on 9 April 1940.
Command and Control
The command and control arrangements followed by the Germans in the joint and naval planning for the offensive against Denmark and Norway built upon existing formal structures as well as considerable unconventional interaction. At the top was Hitler, Nazi Germany’s political leader and supreme commander of the Wehrmacht. Hitler took a personal and active interest throughout the planning and conduct of the operation, to the point of dictating what should be done down to a relatively low level. In retrospect, his strategic insight proved better than that of his more cautious generals, as he accurately predicted the timid responses of the Scandinavian governments and the Western Allies in 1940. The strategic direction and end state were clear, namely to invade and subdue two neighbouring countries within a set time limit. Translation of strategic guidance into definite plans at the operational level was left to the OKW through Keitel and Jodl. Hitler always treated the OKW as his own personal planning staff. In other words, he imposed himself rather than seeking meaningful military advice. For the latter, Hitler consulted directly with the individual commanders-in-chief of the respective armed services. He acted as arbiter in the event of disagreements and generally favoured whoever last talked to him convincingly. In the war’s early years, Raeder still enjoyed Hitler’s confidence to the extent that the German admiral’s ad-vice and suggestions generally received a fair hearing. Raeder, normally a cautious individual by nature, was aggressive toward Norway because he recognized the Kriegsmarine’s classic dilemma. Like Hitler, Raeder also assumed a personal interest in planning and conduct of naval operations against Norway; he constantly delved into matters properly within the purview of his subordinates. Raeder later received a term of life imprisonment from the International Military Tribunal at Nuremberg on a charge of waging aggressive war.
Given the nature of the operation and Raeder’s active involvement, the Kriegsmarine took a leading role in final details for the invasion of Norway and Denmark. The SKL retained control over as-signed naval forces, although Falkenhorst was nominally the joint operational commander. Like-wise, the Oberkommando der Luftwaffe (OKL) exerted similar control over assigned air forces, by appointing the very capable Generaloberst Erhard Milch for the purpose. The level of cooperation between the Kriegsmarine and Luftwaffe was high, certainly far better than before or after invasion of the Scandinavian countries. Vice-Admiral Kurt Fricke, chief of the SKL’s operations branch (1/SKL), filtered most direction from Raeder, Jodl, and Hitler. Key decisions in this risky operation were reserved for the highest level. Despite this, the Marinegruppenkommando West, under Admiral Alfred Saalwächter, acted as the delegated operational authority in Norwegian waters for preparations and other arrangements until establishment of a commanding admiral in Norway, General-Admiral Hermann Boehm being so designated. The principle of having a single naval operational commander in theatre, to which other naval commands would defer, was followed. As an exception, the approximately 20 U-boats in the theatre of operations remained under the purview of the Befehlshaber der Unterseeboote (BdU), Admiral Karl Dönitz. In actual practice, the SKL and, indeed, Raeder himself constantly issued orders and guidance to subordinate commanders in the various naval commands and the naval task groups involved.
The first warship echelon was divided into six separate operational task groups:
Group 1: Vice-Admiral Günther Lütjens with the battle cruisers GNEISENAU and SCHARN-HORST to act as covering force and feint for the northern landings. Commodore Friedrich Bonte with 10 destroyers to land 2,000 troops and occupy Narvik;
Group 2: Captain Hellmuth Heye with the heavy cruiser HIPPER and 4 destroyers to land 1,700 troops and occupy Trondheim;
Group 3: Rear-Admiral Hubert Schmundt with light cruisers KÖLN, KÖNIGSBERG, BREMSE, and two flotillas of motor torpedo boats to land 1,900 troops and occupy Bergen;
Group 4: Captain Friedrich Rieve with the light cruiser KARLSRUHE, depot ship TSINGTAU, and motor torpedo boats to land 1,100 troops and occupy Kristiansand and Arendal;
Group 5: Rear-Admiral Oskar Kummetz with the heavy cruiser BLÜCHER, ‘pocket’ battleship LÜTZOW, light cruiser EMDEN, and motor torpedo boats to land 2,000 troops and occupy Oslo; and
Group 6: Commander Kurt Thoma with the 2nd Minesweeping Flotilla to land 150 troops and occupy the cable station at Ekersund.
Just prior to the invasion, the SKL reported that the groups were “led by excellent Commanders.” In advance of or following the warships were seven merchant ships in a support echelon, an eight-ship tanker echelon, and three further sea transport echelons. Disguised as ordinary commercial shipping, these vessels carried follow-on troops, artillery, ammunition, and fuel once the ports were secured. Because of their slower speed, the merchant ships left German ports a full week before the intended date of invasion, thereby increasing the possibility of accidental discovery. The Marinegruppenkommando West requested that orders be issued to troops to say, if intercepted or captured, that they were proceeding to Iceland, but the OKW felt simply refusing to make a statement was better policy. Sailing merchant ships in advance separate from the warships decreased flexibility in the operational plan and tied the Kriegsmarine irretrievably to the whims of fortune and chance, in turn presenting obvious challenges of command and control.
On the British side, all naval matters were handled through the Admiralty. In April 1940, the First Lord of the Admiralty was Winston Churchill, who was, alongside Hitler, one of the most forceful personalities in the entire war. The First Lord, a sitting member in the House of Commons and the war cabinet, was responsible to Parliament and the Prime Minister. Churchill interpreted and passed on strategic direction for deployment of the Royal Navy’s fleets around the globe and in European waters. It was left to the First Sea Lord, Admiral of the Fleet Dudley Pound, to see that such policy was carried out in an efficient and timely manner. The problem of Norway had preoccupied Churchill and Pound for some time. It was they who had ordered boarding of the ALT-MARK and mining of Norwegian territorial waters in contravention of international law, and they, more than anyone else, forced the Germans into making a decision to invade Denmark and Norway. In fact, a British military expedition, along with accompanying naval forces, was being assembled at the main naval anchorages at Scapa Flow and Rosyth under “Plan R4” just as the German naval task groups left for Norway. Covering the northern Atlantic approaches, the North Sea, and the waters off Norway was the Home Fleet, under the operational command of Admiral Charles Forbes. Forbes, the Commander-in-Chief Home Fleet, had at his disposal a motley collection of older battleships, cruisers, destroyers, and a lone aircraft carrier under work-up on the wrong side of the country, organized into five squadrons and eight flotillas. The commanding flag officers were:
2nd Battle Squadron: Admiral Charles Forbes with the battleships RODNEY, WARSPITE and VALIANT;
Battlecruiser Squadron: Vice-Admiral William Whitworth with the battle cruisers RENOWN and REPULSE;
1st Cruiser Squadron: Vice-Admiral John Cunningham with the heavy cruisers DEVONSHIRE, BERWICK and YORK;
2nd Cruiser Squadron: Vice-Admiral George Edward-Collins with the light cruisers GALATEA, ARETHUSA, PENELOPE, AURORA, MANCHESTER, SHEFFIELD, SOUTHAMPTON, GLASGOW and BIRMINGHAM; and
Destroyer flotillas: Rear-Admiral Ronald Hallifax with the 1st (temporarily attached), 2nd, 3rd, 4th, 5th, 6th, 7th, 8th, and 12th (temporarily attached) Fleet Destroyer Flotillas. There were nine destroyers in a full-strength flotilla (one leader plus eight others).
Submarine Flotillas: Vice-Admiral Max Horton commanding the 2nd, 3rd, 6th, and 10th (French) Submarine Flotillas. Twenty submarines, including three French and one Polish boat, were tasked to this operation.
Forbes’ primary mission was to prevent the breakout of German surface raiders into the Atlantic through the northern route, and his disposition of available British naval forces reflected this concern. Consequently, the eastern part of the North Sea was left virtually devoid of British warships. Instead, the big capital ships were held in readiness at Scapa Flow and they offered seductive targets for the first Luftwaffe bomber attacks against the United Kingdom. Vice-Admiral Horton, the admiral commanding Royal Navy submarines, ran his operations from London. Although a commander-in-chief technically held sway over strictly operational matters in his area of responsibility, Forbes was never the master of his own house. Orders and counter-orders to lower naval commands streamed from Pound and Churchill at the Admiralty, particularly when Forbes was away at sea under wireless silence. A series of misguided Admiralty decisions compounded Forbes’ inability to read true German intentions in the crucial days leading up to the invasion of Norway and Denmark. As a result, the Germans achieved a degree of surprise, on which their earlier planning had pinned so much hope. British aircraft reported large enemy warships at sea on 7 April, but their destination was unknown.
German troops, warships, tankers, and merchant vessels in the transport echelons proceeded to their assigned objectives according to the timetable set out in the “Weserübung” planning. The movement was not without incident. On 8 April, the British destroyer GLOWWORM stumbled into a pair of straggling German destroyers, causing a running battle and then being sunk by gun-fire from the heavy cruiser HIPPER but not before GLOWWORM had rammed and seriously damaged HIPPER, for which her commanding officer was awarded a posthumous Victoria Cross. Meanwhile, a Polish submarine sank the RIO DE JANEIRO, a merchant vessel carrying German troops, off Kristiansand and when the survivors landed ashore their identity and ultimate destination were quickly divined by Norwegian authorities. The SKL worried that all element of surprise had been compromised by these events, but the Norwegian government decided to debate the issue rather than alarm the country or raise the military alert state. Meanwhile, the British Home Fleet still searched for elusive surface raiders. Forbes had sailed every available fleet unit from Scapa Flow on a north-easterly course, and he ordered Whitworth, having completed the cover of mine-laying off the Norwegian coast in RENOWN, southward and then northward “to concentrate on preventing any German force proceeding to Narvik.” In the early morning hours of 9 April, Admiral Whitworth and the battle cruiser RENOWN with a screen of nine destroyers intercepted and engaged GNEISENAU and SCHARNHORST. GNEISENAU and RENOWN both suffered minor damage and then the Germans broke contact with the superior British force by using their speed to good effect in the poor visibility. While the modern German warships’ combined eighteen 11-inch guns outgunned the British battle-cruiser in total volume of fire, RENOWN’s eight 15-inch guns carried far greater hitting power and her destroyers’ torpedoes were potentially lethal. Consistent with Raeder’s doctrine, they evaded a fight they had little chance of winning but, despite this reversal, the Kriegsmarine achieved its larger operational objective. The dramatic battle kept the closest British fleet units busy as German cruisers and destroyers carried troops into the assault on Norwegian ports. Still too far away to interfere was Forbes, with the biggest but slower Home Fleet battleships, which were harassed by Luftwaffe aircraft as the day wore on and as the British fleet closed the Norwegian coastline.
Despite bad weather and stormy seas, the planned German landings occurred at the selected spots along the southern Norwegian coastline on time and in strength. Denmark was overrun with minimal resistance, having decided to accede to German surrender demands instead of fighting; most importantly, the Danish airfields at Esbjerg and Aalborg were secured and quickly made operation-al. The Norwegians, however, were not so accommodating. The Germans encountered opposition from a small number of obsolete Norwegian warships and aircraft as well as troops, deployed mostly in fixed coastal fortifications at strategic points. During Group 5’s approach through narrows to the capital city of Oslo, the Norwegians hit and sank the BLÜCHER by gun and torpedo at point-blank range. The remaining LÜTZOW and EMDEN, the former having sustained some damage, withdrew and landed troops elsewhere to advance on Oslo by land, but not before the Norwegian royal family and cabinet escaped to Britain to direct the continued Norwegian participation in the war. At Kristiansand, two island forts required bombing from the Luftwaffe before KARLSRUHE could approach and land troops from Group 4 in the city. Likewise, Norwegian batteries resisted Group 3’s KÖLN and KÖNIGSBERG on their way into Bergen, seriously damaging the latter. Once the warships were inside the fjord, troops disembarked and occupied the city, while airborne troops landed at nearby Stavanger. Merchant vessels from the sea transport echelons began to arrive and defences were readied in case of attack by the British Home Fleet. Geographically, Bergen was the shortest distance from Scapa Flow and British air bases.
The amphibious assaults against Norway’s northern ports encountered only marginally less resistance. The Germans used deception and deceit to confuse the Norwegian defenders. From Group 2, HIPPER and its destroyers, when challenged, flashed in English the message: “Have orders from the government to go to Trondheim. No hostile intentions,” and travelled past two batteries covering the approaches before opening fire. The batteries were captured by troops landed in their rear, while the Norwegian military at Trondheim surrendered upon German demand. To compound the critical German fuel requirements, two of the tankers were sunk by British submarines. Meanwhile, the destroyers forming Group 1 proceeded toward Narvik. The Germans sank two aged coastal defence ships with torpedoes, one upon signal after a delegation returned from a friendly parley with the Norwegian naval captain. Destroyers disembarked troops pierside amidst a significant amount of shipping in the harbour. Narvik’s acting military commander dallied in the face of German threats and finally surrendered without a fight. In regard to Narvik, the SKL war diary reported on 9 April: “Landing accomplished without difficulty, resistance slight.” The great prize had been won; Narvik was in German hands. The question now was whether the Germans could hold onto it.
Melee in the Fjords
The German naval position in Narvik was tenuous. Now that the troops had landed, the destroyers required refuelling for the return trip south. The SKL had recognized that this phase represented the most critical part of the entire naval campaign. The enemies were time and the Royal Navy. Only one tanker, the JAN WELLEM, a converted whaler which came from Murmansk via the Arctic Ocean, arrived safely in Narvik; the rest from the tanker echelon were notably absent. Unfortunately, the JAN WELLEM could refuel only two destroyers at a time and did not carry enough fuel to do the entire lot. Bonte’s destroyers in Narvik were stranded without fuel to get back home. They were also extremely vulnerable because, despite Goering’s claims, the Luftwaffe could not provide adequate and continuous air cover over Narvik from airfields far to the south. On the other hand, the extreme distance also precluded possible attacks from British aircraft, even long-range bombers. The most immediate danger was, therefore, predominantly naval. The aggressiveness of the Royal Navy was now to come into play.
The Admiralty determined to attack and isolate the German naval forces at Narvik. In the early hours of 10 April, Captain Bernard Warburton-Lee and the 2nd Destroyer Flotilla undertook a reconnaissance-in-force through the fjord right into Narvik’s harbour. Catching the Germans by surprise, his five destroyers sank two destroyers and damaged five more plus several empty transports before the Germans could return effective fire. Commodore Bonte, a personal favourite of Admiral Raeder and considered the best German naval commander, was killed during the action. In the course of withdrawal, however, the daring Warburton-Lee’s luck also ran out when his small force met the alerted German destroyers GEORG THIELE and BERND VON ARNIM, which promptly sank two British destroyers. Warburton-Lee was killed in the process. The other British destroyers retreated with some damage. Afterwards, the Germans considered a breakout with the last serviceable destroyers, but lack of fuel and the suspected presence of strong British warships foiled any attempt. The British marshalled their forces for a coup de grace. On 13 April, the battleship WARSPITE, with Whitworth aboard, plus nine destroyers, and torpedo bombers from the carrier FURIOUS, sallied toward Narvik. The result was an incredible but ultimately one-sided sea battle. The German destroyers were pursued and hunted down into the surrounding fjords. All eight of the remaining German destroyers were either sunk or scuttled. The SKL war diary recorded: “Naval Staff does not doubt for a moment that the Narvik destroyers, with the superb spirit of their commanders, officers and crews, showed themselves worthy of their tradition and offered the most stubborn resistance to the enemy to their last shell and torpedo.” Although the lives of many sailors had been saved, losses in this class of surface warship represented a heavy blow to the Kriegsmarine and its operational capabilities.
German naval forces in other Norwegian ports were anxious not to be trapped in the same manner. Early on 10 April, British diver bombers, flying at extreme range from British bases, attacked and sank the disabled KÖNIGSBERG at Bergen. Eager not to share a similar fate, HIPPER left Trondheim and met up with GNEISENAU and SCHARNHORST for an uneventful run back to Germany. The next day, a flight of torpedo bombers from FURIOUS found in that harbour only three destroyers, which they attacked without success. Aircraft from coastal and bomber commands searched the waters off southern Norway for more targets. Increasing Luftwaffe strength, however, made the proposition very hazardous. British sorties into other Norwegian ports were not at-tempted because it was believed that the Germans now manned captured Norwegian coastal de-fences and guns. Instead, the Home Fleet established sweeps of cruisers and destroyers down the Norwegian coast. Despite these measures, KÖLN successfully evaded these forces and reached Wilhelmshaven safely. KARLSRUHE and LÜTZOW were not so fortunate. The light cruiser and armoured ship cleared their respective ports, but fell victim to a lurking underwater menace.
Submarine and Air Operations
Royal Navy submarines inflicted significant losses on German naval forces, especially among vulnerable merchant vessels in the supporting echelons. Submarine encounters with the transports sailing in advance of the German warships before 9 April were among the first indications that some sort of German assault on Norway was afoot. Accordingly, the Admiralty lifted targeting restrictions in regard to visit and search and allowed sinking of such ships on sight and without warning. Admiral Horton redeployed his forces, some 20 submarines in total, to cover the southern approaches, the Kattegat, and the Skagerrak. These choke-points were natural places to intercept German warships and transports. Horton’s submarines sank upwards of 10 vessels from the support echelons. Most significantly, the valuable tankers earmarked for the northern ports never arrived due to British submarine action. On 9 April, TRUANT sank the returning KARLSRUHE with a single torpedo, and SPEARFISH severely damaged the LÜTZOW with several torpedo hits on 11 April, although the crippled ‘pocket battleship’ eventually made port under tow. Royal Navy submarines also harassed subsequent supply of German forces in Norway by sea. On 12 April, the SKL war diary stated: “Still great danger from submarines in the Kattegat, Skagerrak and Oslo Fjord, forcing the use of all available forces on defense assignments. No submarine-chase successes reported so far in spite of numerous depth charge attacks.” Anti-submarine escorts joined convoys. Sinking submarines was a bonus, but simply keeping them down and inactive achieved the operational mission. In fact, the Germans actually captured a Royal Navy submarine and its crew when they forced SEAL to surface in the Skagerrak. Strengthened German defences and counter-measures made submarine operations progressively more difficult and the returns more costly. At the end of the month, Horton called his submarines back home to count their successes.
German submarine operations, on the other hand, proved a huge disappointment. BdU counted on the landings to draw British warships near or into the fjords. Accordingly, the “Weserübung” naval planning included defensive pre-positioning of U-boats off the approaches to Norwegian ports under the code-word “Hartmouth.” These included four, eventually reinforced by four more at Narvik, two at Trondheim, six at Bergen, and two at Stavanger; others waited in attack positions north and north-east of the Shetlands. Many submarines were commanded by officers with previous operational experience. As expected, Royal Navy ships entered into the snare, but then chance arrived. Time after time, U-boats achieved good firing positions, only to have torpedoes miss or self-detonate before hitting their intended targets. One U-boat commander sent a spread of four torpedoes toward WARSPITE at close range without a single hit. It was later revealed that torpedo failures were attributable to technical defects in depth control and magnetic guidance. The situation was not peculiar to the Kriegsmarine. Similar problems with this intricate and sensitive naval ordnance were encountered in other navies, especially by the US Navy in the Pacific. Dönitz, unwilling to risk his U-boats further in pointless attacks, ordered a withdrawal on 17 April. During the entire Norwegian campaign, German submarines sank no British warships and only a handful of merchant shipping. Fate was definitely smiling on the Royal Navy. In BdU’s war diary, Dönitz frustratedly exclaimed: “I do not believe that ever in the history of war have men been sent against the enemy with such a useless weapon.” The U-boat debacle necessarily constrained smooth implementation of the operational naval campaign.
In addition to submarines, aircraft represented the main instruments of reconnaissance, attack, and sea denial against the opposing fleets. Aircraft either came under naval control and direction or belonged to air forces on a cooperative basis. Larger warships possessed their own aircraft, and during the second foray into Narvik, WARSPITE’s float-plane actually sank a U-boat. The Royal Navy’s Fleet Air Arm was active throughout the naval campaign. Attacks were made against German warships and transports in port and at sea. The British worked under two major limitations: the small number of aircraft carriers in theatre, and unsuitable or obsolete aircraft. The Fleet Air Arm’s relatively low priority in the Royal Air Force’s procurement activities meant that open-cockpit biplanes and slow two-seat fighters were the main strike aircraft available to the Royal Navy. The results were devastating when such aircraft met land-based high-performance fighters. The Fleet Air Arm was literally bled white of brave and experienced personnel through losses to the Luftwaffe off Norway. Indeed, the increasing dominance of the Luftwaffe was a defining characteristic as the naval campaign progressed. The Kriegsmarine’s early attempts to fly its float-planes into Norwegian ports proved largely unsuccessful, due to damage on landing and lack of aviation fuel. Far more important were Milch’s substantial efforts to make operational as soon as possible the Norwegian and Danish airfields captured by paratroops and air-landed assault troops. The proximity of these airfields considerably increased the range and time over target for medium tactical bombers and dive-bombers from X Fliegerkorps, a Luftwaffe formation specially trained for maritime operations. Persistent and accurate air attacks compelled Forbes to keep Home Fleet surface ships out of southern Norwegian waters from 9 April onwards. The Royal Navy was markedly inefficient at anti-aircraft defence, and some ships expended a big share of their available ammunition in first encounters. As days and weeks passed, Milch extended the Luftwaffe’s air umbrella over a wider and wider operational area. Of course, the major limiting factor in air operations remained the weather, which could be notoriously bad off Norway that time of year. Likewise, gaps and incomplete Luftwaffe coverage still pertained in northern Norway, where the British were quick to take advantage.
In the second phase of the campaign, the Royal Navy supported military efforts to retake ports in central Norway and later to evacuate British and French forces when those operations stalled. At the Admiralty, Churchill and Pound demanded definite assessments from the Home Fleet on the feasibility of an opposed landing directly into Trondheim. Forbes seemed willing to make a try, but he cautioned that the air threat put at great risk the safety of his warships, on which most troops would be carried. The German experience already showed what potential fate could befall larger warships within confined waters; moreover, SUFFOLK had suffered terrible damage when coming back from a hit-and-run raid against Stavanger, during which the Luftwaffe flew some 80 sorties against the British cruiser over a seven-hour period. The decision was made to land troops in-stead south of Trondheim, at Aandalsnes, and further north at Namsos, with the intention of making a pincer movement. Naval forces secured the landing sites with no resistance, and the main forces began disembarkation on 15 April. Meanwhile, the Fleet Air Arm attacked German-held airfields, in an effort to neutralize the advantage of German air power. The battle for local air superiority remained decisive as the Luftwaffe appeared in force to challenge the British incursions. The Germans relentlessly bombed the two towns and any ships they could find there. One British naval captain reported that Namsos was on fire from end to end. Many supplies were destroyed, and Allied troops took refuge in surrounding forests. As more German military reinforcements arrived by air and land, the prospect of making successful advances on Trondheim became increasingly unlikely. The race for a build-up of combat power ashore gradually turned against the British. On 28 April, a general withdrawal from central Norway was ordered. Warships and transports, accompanied by special anti-aircraft auxiliaries, evacuated troops and equipment from first Namsos and then the areas surrounding Aandalsnes. The Royal Navy fought its way out from the Norwegian fjords against Luftwaffe air attacks. GLORIOUS and ARK ROYAL, two aircraft carriers recently arrived from the Mediterranean, provided covering fighter support. German pilots, in accordance with their standing instructions and ignoring Corbett’s advice always to sink the transports first, targeted the aircraft carriers, but scored only minor hits. Battered British convoys cleared the coastline and shaped their course for home.
As events around Trondheim unfolded, the British proceeded with offensive naval and military operations in northern Norway against Narvik. Admiral Lord Cork, the naval force commander, initially pushed for a direct amphibious assault on the town, but hesitation from the War Office and the appointed land force commander favoured a more indirect approach. Although cut off and tired, German troops and sailors in Narvik still held a reasonably good defensive position. The Luftwaffe delivered only limited supplies under Hitler’s express orders, which also told the men there to hold on and fight to the death. On 24 April, Royal Navy cruisers and destroyers closed and bombarded the town. Cork curtly reported to the Admiralty: “Narvik is burning.” Nonetheless, due to weather and continued fears of German resistance, only small parties of troops were landed at two places some distance from Narvik. Over the next week, the British made additional seaborne landings at key spots along the coast, in an attempt to delay a strong German relief column moving up from Trondheim over terrain previously considered impassable. The Luftwaffe supported this northward movement and opened up new operational airfields close behind. Again, the British were in a race to build up combat power ashore and to secure the objective. With fire support from the Royal Navy, British and French troops landed, attacked, and captured Narvik on 28 May, pushing the German defenders into the mountains. But Cork had already received instructions from the Admiralty to withdraw all forces from Norway because military operations in France were not going well; evacuation from Narvik occurred between 4 and 8 June. Troops and equipment were loaded onto transports and sailed by convoy under warship escort. The Luftwaffe only slowly appreciated that a British withdrawal from Narvik was taking place, and it could do no more than nip at the Royal Navy’s heels. The SKL, on the other hand, had sailed a naval force on 4 June, consisting of SCHARNHORST, GNEISENAU, HIPPER, and four destroyers. The original intent for this group was to support the beleaguered German forces at Narvik, but now the prey became the British convoys. The catch proved meagre until SCHARNHORST and GNEISE-NAU ran across and sank the aircraft carrier GLORIOUS and her two escorting destroyers by gun-fire. Forbes scrambled the Home Fleet to intercept the German warships, but the latter gained safety in Trondheim harbour under the protective cover of the Luftwaffe. The Kriegsmarine laughed last in the Norwegian campaign.
During the naval campaign for Norway and Denmark, timely and accurate intelligence was crucial to operations of the opposing naval forces. It was the main means by which operational commanders gained an appreciation of the enemy’s intentions and framed their own actions and responses. Both sides made wide use of aerial reconnaissance, when weather permitted. Flights from the Fleet Air Arm and Coastal Command confirmed whether German warships were in Norwegian ports. Likewise, the Luftwaffe used regular patrols to locate individual units and formations from the Home Fleet. The Germans used this information to direct coordinated attacks by aircraft, surface ships, and U-boats. The OKL and SKL also seemed reasonably well-informed about dis-positions and the situational picture at any given time. In contrast, the Admiralty often made decisions or issued orders in the absence of reliable information from in-theatre forces. As well, signals intelligence played a hugely significant role, a fact only recently appreciated by historians due to previous secrecy restrictions. Breaking of the German Enigma codes allowed the British to follow Luftwaffe movements as well as limited naval movements. Allied leaders also had access to highly secret Ultra intercepts, although in the early part of the world war, this resource was not fully exploited. Most significantly, the German invasion of Denmark and Norway came as a surprise to the highest levels of the British political and military establishments. Nonetheless, the in-formation exchange was not entirely one-sided. The Kriegsmarine’s excellent naval intelligence service, B-Dienst, read the Royal Navy’s secret ciphers used for ship-to-ship as well as ship-to-shore messaging. The information gained allowed German surface ships to evade pursuing British naval forces and revealed the location and timing of British amphibious landings. Strict wireless silence observed by many British naval commanders somewhat obviated the German advantage. As with most intelligence in general, the major challenges during the naval campaign were volume, analysis, and timeliness of information.
The naval campaign for Norway and Denmark in 1940 represents an example of power projection by naval forces in a littoral environment. The German seaborne invasion involved enormous risk, in terms of force protection and maintenance of future operational capabilities. The Kriegs-marine faced a numerically superior and aggressive foe in the Royal Navy. Success in the initial landings was due in large part to detailed planning and the maintaining of the element of surprise. The Germans reached out and grabbed Norway right out from underneath the gaze of the Royal Navy. However, key assumptions and concessions in the campaign planning left German naval forces vulnerable to British counteroffensives, particularly in central and northern Norway. Subsequent operations demonstrated the vital importance of air superiority and maritime control over waters close to shore. Despite the best efforts of the Royal Navy, the Germans withstood Allied attempts to regain key territory and ports in Norway. For Hitler and Raeder, the Scandinavian gamble paid off. Norway and Denmark remained in German hands. The syndicate should now consider how the operational concepts and historical experience from the naval campaign for Norway and Denmark have relevance to a naval component commander in a similar situation today.
The German Rank System
Every officer candidate started off as a sailor working his way up, generally in three years, via midshipman to ensign. Officers joined in year classes, known as “Crew Years” or “Crews” for short. Erich Raeder and Wolfgang Wegener were members of the same crew. The German ranks system does not equate exactly to that of the British or American system.
Fähnrich zur See FzS Midshipman
Oberfähnrich zur See OfzS No Equivalent
Leutnant zur See LtzS Acting Sub-Lieutenant/Ensign
Oberleutnant zur See OLtzS Sub-Lieutenant/Lieutenant J.G. — CO of small Submarines, MHCs, FPBs
Kapitaenleutnant KptLt Lieutenant/Lieutenant S.G./
CO of Submarines, FPBs, MHCs
Korvettenkapitaen KKpt Lieutenant Commander/junior Commander
— CO of Submarines, FPBs, Tenders
Fregattenkapitaen FKpt Commander — CO of FFGs, DDGs.
Kapitaen zur See KptzS Captain(N) — CO of flotillas, large warships
The flag ranks are as follows:
Kommodore/Flotillen Admiral Commodore/Rear-Admiral lower half
Konter Admiral Rear-Admiral
Vize Admiral Vice-Admiral
General Admiral No equivalent
Gross Admiral Admiral of the Fleet
The German army rank system also had some non-equivalent flag ranks. The ranks of Colonel-General existed between Lieutenant-General and General, which was, like Admiral in the navy, a proper rank.
Available through the IRC:
Assmann, Kurt. “The German Invasion of Norway, 1940” in Merrill L. Bartlett, ed. Assault from the Sea: Essays on the History of Amphibious Warfare. Annapolis: Naval Institute Press, 1983, 236–248.
Barnett, Corelli. Engage the Enemy More Closely: The Royal Navy in the Second World War. New York: Norton, 1991.
Befehlshaber der Unterseeboote. War Diaries of the German Submarine Command, 1939–1945. Wilmington: Scholarly Resources, 1984. Reel No. 1.
Brodhurst, Robin. Churchill’s Anchor: Admiral of the Fleet Sir Dudley Pound. Barnsley: Leo Cooper, 2000.
Brown, David, ed. Naval Operations of the Campaign in Norway April–June 1940. London and Portland, OR: Frank Cass, 2000.
Claasen, Adam R.A. Hitler’s Northern War: The Luftwaffe’s Ill-Fated Campaign, 1940–1945. Lawrence: University Press of Kansas, 2001.
Corbett, Julian. Some Principles of Maritime Strategy. Annapolis: Naval Institute Press, 1972.
Derry, T.K. The Campaign in Norway. London: Her Majesty’s Stationery Office, 1952.
Dönitz, Karl. Memoirs, Ten Years and Twenty Days. London: Wiedenfeld and Nicolson, 1959.
Gemzell, C. Organization, Conflict, and Innovation: A Study of German Naval Strategic Planning, 1888–1940. Lund: Esselte Studium, 1973.
German Naval Staff. War Diary, Operations Division, German Naval Staff, 1939–1945. Washington, DC: Operational Archives Branch, US Naval History Division, 1971. Reel TM-100-B.
Harner, David J. Bombers versus Battleships: The Struggle between Ships and Aircraft for the Control of the Surface of the Sea. Annapolis: Naval Institute Press, 1998.
Herwig, Holger H. “The Failure of German Sea Power, 1914–1945: Mahan, Tirpitz, and Raeder Reconsidered.” International History Review 10 (February 1988): 68–105.
Hinsley, F.H. British Intelligence in the Second World War. London: Her Majesty’s Stationery Office, 1979.
———. Hitler’s Strategy: The Naval Evidence. Cambridge: University Press, 1951.
Hooker, Richard D., and Christopher Coglianese. “Operation Weserübung and the Origins of Joint Warfare.” Joint Force Quarterly 1 (1993): 100–111.
Kersaudy, François. Norway 1940. New York: St. Martin’s Press, 1991.
Martienssen, Anthony K. Hitler and His Admirals. New York: E.P. Dutton, 1949.
Moulton, J.L. The Norwegian Campaign 1940: A Study of Warfare in Three Dimensions. Athens, Ohio: Ohio State University Press, 1967.
Raeder, Erich. My Life. Annapolis: Naval Institute Press, 1960.
Roskill, Stephen. Churchill and His Admirals. London: Collins, 1977.
———. The War at Sea 1939–1945. The Defensive. London: Her Majesty’s Stationery Office, 1954.
Ruge, Friedrich. Der Seekrieg: The German Navy’s Story 1939–1945. Annapolis: Naval Institute Press, 1957.
Showell, Jak P. Mallmann. The German Navy in World War II. Annapolis: Naval Institute Press, 1979.
Showell, Jak P. Mallmann, ed. Fuehrer Conferences on Naval Affairs, 1939–1945. London: Greenhill, 1990.
Thomas, Charles S. The German Navy in the Nazi Era. Annapolis: Naval Institute Press, 1990.
United States. Chief Counsel for Prosecution of Axis Criminality. Nazi Conspiracy and Aggression. Washington, DC: US Government Printing Office, 1946.
Vian, Philip. Action this Day. London: Muller, 1960.
Warlimont, Walter. Inside Hitler’s Headquarters, 1939–45. London: Weidenfeld and Nicolson, 1964.
Wegener, Wolfgang (Holger H. Herwig, ed. and trans). The Naval Strategy of the World War. Annapolis: Naval Institute Press, 1989.
Ziemke, Earl F. The German Northern Theater of Operations, 1940–1945. Washington, DC: Department of the Army, 1959.
Other Recommended Resources not Held in the IRC:
Gilbert, Martin, ed. The Churchill War Papers, Vol. 1: At the Admiralty September, 1939–May 1940. London: Norton, 1993.
Whitley, Michael J. Destroyer: German Destroyers in World War II. Annapolis: Naval Institute Press, 1991.