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U-boats of the Imperial German Navy at the beginning of WW I (Part 1)

Not unexpectedly, also in 2014 and 2015 the recurrence of “round jubilees” will see another series of articles in the media, whether it will be birthdays, anniversaries of deaths of famous persons, or historic events, usually upwards from the 50th recurrence. This year, somewhat tragic events in history will be the cause for that. Hence, we will see not only numerous articles, but also books, TV and movie documentaries and plays dealing with the 100th anniversary of the beginning of WW I and the 75th anniversary of the outbreak of WW II. In 2015, we expected another series of publications about the sinking of the Lusitania in 1915. Even rather isolated events in both wars will find again many reflections and presentation of allegedly new research, ranging from the question who is responsible or has to take the blame for causing the troubles, up to some overall assessment of the conduct of war.

The war at sea as waged by U-boats has seen a weal literature and filmic documentaries, also wide response in light literature as well as the world of theater and movies. All those might only represent a small part of the entire events in the wars. Notwithstanding, armament programs, technical developments, training and actual employment in battle of U-boats can be a most valuable mosaic in finding an overall assessment of the question of war preparation, in the end even war guilt.

Again, one can find a number of myths having developed during this process of presentation of war events, especially as U-boats generally are considered to be a particular aggressive means of waging war.

The role of the German Reich at the outbreak of war of WW II is rather indisputable. The detachment of available Kriegsmarine U-boats to preplanned areas of operation many days before the 01 September 1939 provides some very sound proof of the advanced preparation for war at the side of Germany.

Much less clear is the assessment of the causes of WW I. If one examines the armaments programs, the combat readiness training and the dislocation of the U-boats of the Imperial German Navy immediately before and throughout the first months after the outbreak of war on 01 August 1914, to using it as “mosaic” for an overall assessment of the causes of the war, it is far from clear who caused war and what led to war. On the other hand, it has to be remarked that the U-boats have played only a minor role in the military planning of the German Reich well into the years of war, as one was convinced of the need for only a short war, waged decisively by a powerful Army and a High Seas Fleet, that soon will fight the one and only decisive sea battle.

Despite the initially obvious subordination of U-boats the following article will present and evaluate what size of a U-boat force the Imperial German Navy maintained at the beginning of war in 1914, and what war plans did exist for the U-boats. Also, it will be shown how many U-boats were under construction at that time. Above all, it will be examined what operations the U-boats executed during the last days before the outbreak of war and during its first months.

Until 1914 the Imperial German Navy has seen an enormous armaments program, which consumed at some time about 50 % of the entire armament budget of the Imperial German Armed Forces as a whole. The Fleet Act of 1898 and 1900 plus the supplementing Fleet Amendments of 1906, 1908 and 1912 gave an absolutely dominant role to the buildup of a large fleet of major combatants, pushing smaller units such as minesweepers, coastal patrol boats, later also torpedo boats, as well as U-boats to be marginal notes. For a first time the Fleet Amendment of 1906 budgeted some money for further tests and trials of the so far rather unknown Naval asset “U-boat”, after the Germania Shipyard at Kiel had been given a 1,5 Mill. Reichsmarks building order for U 1 on 03 Dec 1904, being the first U-boat for the Imperial German Navy. It was laid on keel on 10 Dec 1905, and the commissioning occurred on 14 Dec 1906. Only 2 years after that construction and commissioning of U 2 happened at the Imperial Shipyard at Danzig. With that Germany was a rather latecomer in the buildup of a submarine force: states such as Italy (1895), France (1896), the USA (1898), Spain (1898), Britain (1902), Russia (1904) and Sweden (1904) had started already to build submarines or ordered them. Nevertheless, the assessment of the U-boat as a means for contributing to the sea power of a state still was a rather unknown factor in all states, with all of them investing heavily in powerful and by and large big warships.

The following tabs will provide for an overview about the inventory and the further buildup of U-boats in the Imperial German Navy of the German Reich until the e 1914, including those U-boats only ordered until the end of 1914.

At the beginning of the war on 01 Aug 1914 a total of 28 U-boats were commissionedp172_1_00

The “Petroleum” (Kerosene)-U-boats of the I. U-Flottila at Kiel (Foto: German U-Boat Museum)

With that, 28 U-Boats had been commissioned at the beginning of the war, with only the 14 “Petroleum”(Kerosene)-Boats U 5 to U 18 ready for frontal employments, however, limited only due to the heavy smoke exhaust, and U 11 plus U 12 just undergoing extended maintenance. This left just 12 U-Boats ready for employment. Only 4 further U-Boats (U 19 to U22) were combat ready from the fleet of the improved Diesel-Uboats. These figures are mentioned by the official narrations of the War at Sea 1914-1918 by Spindler and Michelsen (see under literature). Assuming between 3 and 6 months combat readiness training and remaining technical works after commissioning further 10 U-Boats (up to U 32) were joining the fleet of front line U-Boats until the end of 1914. Further 6 U-Boats were commissioned until the end of 1914, but did not complete their combat readiness training. Another 23 U-Boats were under put under construction until the end of 1914, but did see commissioning (U 42 exempted) only in 1915.

Comparison to the situation at the Kriegsmarine: 57 U-Boats had been commissioned until 01 Sep 1939, with 22 of those employable at high seas, plus 6 more to come until the end of 1939, plus further 13 under construction.

U-Boats in the operational planning of the Imperial German Navy until the beginning of the war

The historian Rahn mentions in his article (see under literature) a “war gaming” initiated by the German Admiralty in 1912 that simulated the intended courses of action during a war at sea against Britain. It demonstrated that the distant blockade in the North Sea assumed the country would establish against Germany would not be broken by the one and only decisive sea battle between the German High Seas Fleet and the British Grand Fleet, as such a battle cannot be forced by Germany upon Britain. It foresaw rather precise the actual conduct of war in the North Sea, with two fleets essentially just waiting for each other, only encountering one another during few thrusts and, of course, during the non-decisive Battle of Jutland. Although the further operational planning paid more attention not only to fighting worldwide against British sea lines of communication, e.g. through forming a German East Asia Squadron in the Pacific Ocean, but also to examine a German counter-blockade before the British coast, the German High Seas Fleet continued to be destined by and large to seek the one and only decisive battle in the North Sea. Consequently, when the war started the General Operations Plan for the North Sea concentrated at the initial phase on targeted minelaying ops as well as some U-boat ops besides a few smaller size thrusts by surface forces, with the aim to break the British distant blockade and to establish some sort of counter-blockade. After an appropriate balance of forces would have been reached all forces would then seek the great battle at sea to eventually decide the war at sea as such. With that, except some minor operations the German High Seas Fleet in the North Sea was condemned to a mere “Fleet in Being”, i.e. deterrence through simple presence as developed by Grand Admiral von Tirpitz´s grand strategy. The losses suffered during the first own thrusts and while fighting British thrusts in the first months of the war at sea led to even further restrictions to the employment of the major war ships. And, it was Emperor William II himself who directed clearly after those bad experiences gained in the encounters at sea with the British to remain defensive and rather maintain readiness without risking any further major losses.

Therefore, the U-boats were given a rather subordinate role in that operational planning acting as mere advanced coastal patrol boats or minelayers, offensive actions on opportunity basis only, i.e. by chance, against British warships. Trade war at sea was to be conducted strictly in compliance with the international prize law. In his well-received book about German U-boat construction the German author Rössler (see under literature) describes the formation of a German U-boat force and its employment in a war at sea proposed in 1912 by the “Torpedo Directorate” ( which became an own-standing “U-boat Directorate” in 1914). According to that out of a fleet of 70 U-boats to be built until 1920 some 36 U-boats were to execute the mission “Securing the German Bight”, another 12 U-boats to “Securing the Kiel Bight, the Danish Belts and the Fehmarn Belt”, and the remaining 12 U-boats to execute “Offensive operations against the blockade of the North Sea”. This calculation includes the usual division of forces into three groups, i.e. one third is on mission, one third on transit or in regeneration, and the last third in maintenance or training. As an example: The mission “Securing the German Bight” was to be facilitated by U-boats on station at a circle line at a distance of 30 nm around the Island of Heligoland, the U-boats would form the so-called “U-boatline”.

SM U-8 (Foto: German U-Boat Museum)

The building program resulting from that as taken into the Fleet Amendment of 1912 did plan from 1915 onwards an annual budget between 15 and 19 Mill. Reichsmarks to construct 3-6 U-boats per year, this as a follow on program to the approved running building program until 1914 that included the construction of U-boats up to U 41 (annual budget for that = 20 Mill. Reichsmarks). The total budget for the building program 1915 onwards was set to 96 Mill. Reichsmarks (As a comparison: the budget for the Battle Cruiser Derfflinger alone was 56 Mill. Reichsmarks). However, the operational ideas in 1914 as mentioned above to establish a counter-blockade by U-boats against the British distant blockade in the North Sea would have resulted in an amazing fleet of 222 U-boats required to occupy an intended 48 sea areas of blockading. Understandably, these figures were beyond any budget capabilities. Nevertheless, during the course of the war at sea plans were developed repeatedly to blockade selected sea areas off British ports by U-boats, i.e. this operational option in the war at sea was generally kept alive.

It can be concluded that there were some ideas on how to employ the U-boats. Naturally, these ideas could not build on tactical and strategic experiences gained in U-boat combat operations yet, as there were not any yet. Hence, the U-boats was tasked mainly for reconnaissance, forward coastal patrol and the odd targeted fight against enemy Naval forces during single combat patrols. Any trade war by U-boats was excluded initially as a new facet of the war at sea due to constraints seen by International Law (The London Declaration of the International Law of the Seas of 1909). That meant hostile action against enemy merchant vessels only in strict compliance with the Prize Law.


KTB von U 5 bis U 30

Text: Peter Monte – Picture: Deutsches U-Boot-Museum


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  • Diwald, Hellmut: Seemachpolitik im 20. Jahrhundert, Droemersche Verlagsanstalt, München 1984
  • Franken, Klaus: Vizeadmiral Karl Galster – Ein Kritiker des Schlachtflottenbau der Kaiserlichen Marine”, Verlag Dr. Dieter Winkler, Bochum 2010, ISBN 978-3-89911-1367-8
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  • Lipsky, Florian und Stefan: Deutsche U-Boote, Verlag Mittler & Sohn, Hamburg 2006, ISBN 978-3-8289-5411-3
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