UNTERNEHMEN WESERÜBUNG APRIL 1940: THE GERMAN AND ALLIED STRATEGY AND OPERATIONAL APPROACHES IN NORTHERN EUROPE 1939–40 Werner Rahn (in cooperation with Milan Vego) The Strategic Setting1 Hitler’s “Directive No. 1 for the Conduct of War” of 31 August 1939 stated that “The navy will operate against merchant shipping, with England as the focal point.”2 This was the foundation upon which the first naval oper- ations against Britain were based, however, the Naval Staff knew very well Germany’s dilemma, as a continental power that was forced to wage war against the superior British naval power. In an armed conflict, Britain’s geographical position was “disastrous for Germany”, as Admiral Erich Raeder had concluded in 1929.3 Therefore, it is no surprise that in early October 1939 the first idea of obtaining naval bases in Norway came from Raeder. In a staff conference he stated that: The Fuehrer be informed as soon as possible of the opinions of the Naval Staff on the possibilities of extending the operational base to the north. It must be ascertained whether it is possible to gain bases in Norway under the combined pressure of Russia and Germany, with the aim of improving our strategic and operational position.4 1 This chapter is based on Klaus A. Maier, Horst Rohde, Bernd Stegemann and Hans Umbreit: Germany and the Second World War, vol. 2, Germany’s Initial Conquests in Europe. (Oxford 1991) and an unpublished operational case study by Milan Vego (US Naval War College, Newport, R.I., 1993/96). 2 The original German document was published in the edition Walter Hubatsch (ed.): Hitlers Weisungen für die Kriegführung 1939–1945. Dokumente des Oberkommandos der Wehrmacht (first edition: Frankfurt/Main 1962, second revised edition Koblenz 1981). The following edition included all war directives in a correct translation, H.R. Trevor-Roper (ed.): Hitler’s War Directives 1939–1945 (Final edition Edinburgh, 2004), pp. 38–40. 3 Memorandum of the Naval Command to the then Minister of Defence Groener, 28 May 1929: Braucht Deutschland grosse Kriegsschiffe? (Does Germany Need Big Warships?), published in Werner Rahn: Reichsmarine und Landesverteidigung 1919–1928. Konzeption und Führung der Marine in der Weimarer Republik (Munich 1976), pp. 281–86. Cf. also Rahn: German Naval Strategy and Armament, 1919–39, in Phillips Payson O’Brien (ed.): Technology and Naval Combat in the Twentieth Century and Beyond (London 2001), pp. 109–27. 4 See Kriegstagebuch der Seekriegsleitung 1939–1945, Teil A, Bd. 2 (Vol. 2), p. 27 ff. (3 Oct 1939). The War Diary of the German Naval War Staff, Operations Division, (part A) was edited <UN> 332 werner rahn with milan vego On 10 October, Raeder explained to Hitler that the conquest of the Belgian coast would be of no advantage for U-boat war against Britain. He pointed out the advantages of bases on the Norwegian coast and mentioned the possibility of obtaining bases in Norway “with the help of Russian pres- sure”. He also “stressed the disadvantages which an occupation of Norway by the British would have for us: the control of the approaches to the Baltic, the outflanking of our naval operations and our air attacks on Britain, the end of our pressure on Sweden”, and further, “the advantages for us of the occupation of the Norwegian coast: outlet to the North Atlantic, no possibility of a British mine barrier, as in the year 1917–18”. Hitler agreed to take the question of Norway under consideration.5 The Allies knew that Germany was “relatively deficient in good high-grade iron ores, and she had relied mainly on the north Swedish mines since 1919”.6 And so, as early as 19 September and again on 29 September 1939, the First Lord of the Admiralty, Sir Winston S. Churchill raised the issue of the transportation of Swedish iron ore from Narvik to Germany in the Cabinet. He argued “that an adequate supply of Swedish iron ore is vital to Germany, and the interception or preventing of these Narvik supplies for the Militärgeschichtliches Forschungsamtes in conjunction with the Federal Military Archives and the Marine-Offizier-Vereinigung by Werner Rahn and Gerhard Schreiber (Herford and Bonn 1988–1997) [herafter abbreviated as KTB/Skl, part A]. Of the 68 vol- umes, the volumes 1–10 are those especially relevant for Unternehmen Weserübung. The Naval War Staff (Seekriegsleitung), in short Naval Staff or Skl, was the key element within the German Naval Command (OKM), responsible for strategic and operational planning. The English translations of some of the volumes were completed in 1946–49 under the supervision of the US Navy’s Office of Naval Intelligence. A typescript copy of the transla- tion is held in the Naval Historical Center, Washington D.C., and a nearly complete set at the US Naval War College, Newport, R.I. In this paper the war diary quotations are based on the typewritten edition of the translation. See also parts of the translation in Churchill: The Second World War, vol. 2, p. 483. 5 Based on a letter from Raeder to Vice Admiral Assmann, 10.1.1944, quoted in Walther Hubatsch: “Weserübung”. Die deutsche Besetzung von Dänemark und Norwegen 1940 (2nd rev. ed. Göttingen 1960), p. 29ff. Churchill: The Second World War, vol. 2, p. 483 and Fuehrer Conferences on Naval Affairs 1939–1945, p. 47. The notes of these conferences were first pub- lished in English in 1948 in Brassey’s Naval Annual. In this version, however, the original texts were abridged in places, and some important annexes to the conferences are missing. The unaltered reprint of the 1948 edition: Fuehrer Conferences on Naval Affairs 1939–1945 (Annapolis, 1990) was published without mentioning the missing sections. For another translation see the typewritten edition of the US Navy: Fuehrer Conferences in Matters deal­ ing with the German Navy, 7 vols. (Washington, D.C. 1947) in the Library of the US Naval War College, Newport, R.I. In German these are available as Gerhard Wagner (ed.): Lagevorträge des Oberbefehlshabers der Kriegsmarine vor Hitler 1939–1945 (Munich 1972). 6 W.N. Medlicott: The Economic Blockade, vol. 1 (London 1952), p. 30. For further details see ibid. pp. 180–192, and James R.M. Butler: Grand Strategy, vol. 2, September 1939–June 1941 (London 1957), pp. 91–97. <UN> <UN>.