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U-boats of the Imperial German Navy at the beginning of WW I (Part 2)

The first months of the war at sea

One is well advised to consult the logbooks and war diaries as well as the presentations by responsible persons, such as the first “Führer der U-Boote” (= “Commander Submarines”), Commander Wilhelm Bauer (see under literature), who was the Commanding Officer 1st U-Flotilla and was appointed as overall commander for all U-boats at the end of August 1914. These documents show that the U-boats of the Imperial German Navy executed their defined training patterns to gain and maintain their operational readiness being stationed throughout at the peace Naval bases at Kiel and Wilhelmshaven. No particular combat training in certain sea areas (e.g. around the British Isles) in preparation for war can be identified during the last days before the beginning of war, and there was no speeding up of the ongoing training or the building programs. Notwithstanding, a plan for mobilization in case of war had been drafted, which assigned U-boats to new war times bases and new combat missions, e.g. to occupy preplanned advanced guard positions in the German Bight against possible thrusts by British Naval forces.

In the afternoon of the 30 July 1914 all military establishments and units received the warning order of “Outbreak of War Threatening”, which in turn required activating the existing mobilization plans. It meant for the U-boats of the Imperial German Navy to prepare for re-deployment to pre-planned bases. The execution of plans by the early U-boats of the 1st U-Flotilla with Petroleum-driven engines (U 5 to U 18) required them to re-deploy from Kiel in the Baltic Sea to the Island of Heligoland in the North Sea. And so it happened: 9 U-boats (U 5/ U 7/ U 8/ U 9/ U 10/ U 15/ U 16/ U 17 and U 18) left Kiel on 31 July 1914 at 03.00 hrs in the morning, to arrive at Heligoland on 01/ 02 Aug 1914. U 13 arrived as straggler on 04 Aug 1914. Also, the ready trained first 4 Diesel-Uboats (U 19/ U 20/ U 21 and U 22) of the 2nd U-Flotilla in build-up at Wilhelmshaven re-deployed to Heligoland, to arrive there on 04 Aug 1914. There was great urgency to improve the combat readiness of the U-boats. The pressure tanks for submerging and surfacing had to be amended to improve the alert diving time of the U-boat from 5-7 minutes so far to 1-2 minutes. Also, the complicated folding of the radio masts before diving and their re-erecting after surfacing constituted further restrictions to the operational capabilities. These modifications did occur in the time to follow only, so it was obvious at the beginning of the war: Despite having been trained well in peacetime, the U-boats were not as combat ready as the challenges of the war at sea would require.

These were the conditions in August 1914 when the U-boat force entered the war, just roughly 1,000 men within an Imperial German Navy of about 80,000 personal.

The Commander Submarines, Commander Wilhelm Bauer, (see under literature) as well as the war diaries of the U-boats sent into combat (see under sources) offer a good overview about the events during the first months of the war at sea. As a matter of urgency, it was an precautionary measure to immediately establish several advanced guard barriers in the German Bight in execution of the mobilization plan, the inner one forming a circle line from Southwest over North to Southeast distance about 29 nmi from lightvessel Elbe 1 south of Heligoland, being occupied eventually by 7-8 U-boats. This happened at a time the German Reich was not even in a formal state of war. However, the given constellation of Allies (Germany and Austria-Hungary against the “Entente” powers of Britain and France plus Russia) did call for certain preparations. The following events leading to WW I justified the established guard lines at sea soon: On 28 July 1914 Austria declared war against Serbia, on 29 July 1914 Russia mobilized in parts against Austria, and on 01 Aug 1914 at 18.00 hrs Germany declared war against Russia, followed by the declaration of war against France on 03 August 1914 at 18.00 hrs. Once German Forces advanced into neutral Belgium Britain declared war against Germany on 04 August 1914 at 23.00 hrs. With that, it was clear: The German U-boats would face the British Royal Navy as main opponent in the North Sea. What had been examined in studies and developed in operational plans was to see the challenges of the reality of war – and find out whether the plans were effective or useless.


On 06 Aug 1914 at 03.30 hrs the 1st U-Flotilla left Heligoland with all U-boats available, to follow the operational order No. 1 of 05 August 1914 that had already made significant changes to the original mobilization plan. Rather than occupying fixed guard lines and positions in the German Bight the U-boats would form a line abreast 70 nm long to sweep the North Sea executing a large reconnaissance mission from South to North. The mission was to seek for possible units and formations of the Royal Navy. The 9 U-boats forming an West-East line abreast would pass with northerly course three lines , with line 1 east of the Dogger Bank and line 2 and 3 halfway between the Orkney Island and Southwest Norway in the area of Stavanger. Date of return was set to 10 Aug 1914. There were first encounters with the Royal Navy at the Northern end of the reconnaissance sweep off the Scottish coast, during which U 13 and U 15 were lost. With that, the first and somewhat offensive operation by 9 U-boats had experienced losses of 2 boats.

p336_1_01On 08 August 1914, the 4 U-boats employable by the 2nd U-Flotilla departed Heligoland for a reconnaissance mission to the Eastern approaches of the English Channel up to a line lightvessel Maass and lightvessel Outer Gabbard. These first operations of German U-boats in the war at sea 1914-1918 demonstrated the ongoing search (at least by the U-boat Command) for a best possible employment of the U-boats, which by all means wanted to reduce the binding of those few U-boats available then to rather stationary guard duties.

The further employment of U-boats concentrated on more reconnaissance missions up to the East coast of Britain, although a limited number of guard duties in the German Bight were continued at the same time. More and more it became clear that the Royal Navy by no means intended to seek the decisive sea battle with the German High Seas Fleet, rather putting its effort into establishing and guarding a distant blockade in the Northern North Sea and off the eastern approaches to the English Channel. The surprise thrust on 28 August 1914 by a British battle group composed of several cruisers, destroyers and 8 submarines to about 35 nmi off Heligoland on 28 August 1914 ended involving heavy losses to the Imperial German Navy (total loss of the light cruisers SMS Köln, SMS Mainz and SMS Ariadne plus the torpedo boat V-187, with 712 deaths, 149 wounded and 381 taken PoW), while own losses were light only (cruiser HMS Arethusa battle damage only, a total of 35 fallen). This led to even further restrictions to the employment of German surface forces. Another blow to the overall assessment of the German operational capabilities was that the German U-boats did not even manage to join the fight against the British thrust as they were simply not ready in time to sail. On the other hand this event demonstrated the importance of wide range reconnaissance by German U-boats and offensive employment targeted against enemy surface forces, to challenge more effective the beginning British blockade and to ideally establish some sort of a counter-blockade of British ports by German U-boats. This became even more important as Britain on 02 Octoberober 1914 closed the English Channel east of a line Dover-Calais by mines and declared on 02 Nov 1914 in clear violation of International Law the entire North Sea to be a “Military Area”, i.e. forbidding de facto any trade across the sea from and to Germany.

The following months until the end of 1914 were marked by more reconnaissance missions executed by U-boats. As of 01 September 1914 the system of rather stationary guard duties in the German Bight by individual U-boats was changed to a defined system of readiness duties facilitated by 3-7 U-boats Northwest of Heligoland and 5-6 U-boats off the estuary of river Ems. However, the military situation in the Baltic Sea required to detach 3 new frontal U-boats to that sea area in Septembertembertember 1914, with the U-boats returning only in 1915 (U 23 in Februaryruary, U 25 in April, and U 26 as late as August). With that, there were only few U-boats left to continue reconnaissance and offensive actions against British combatants. Some of these few were lucky, when they achieved spectacular successes: On 05 September 1914 U 21 managed to sink the British cruiser HMS Pathfinder, and on 22 September 1914 U 9 sunk within 1:30 hrs an amazing three British cruisers (HMS Aboukir, HMS Hogue and HMS Cressy). Suddenly, the U-boats demonstrated their effectiveness in the war at sea, while at the same time proving that offensive actions would lead to much better results than the stubborn upholding of stationary guard and securing duties in the German Bight.

Also, the overall estimate of the military utility of the U-boat as means of warfare at sea changed remarkably well beyond the Naval leadership. But, it also raised some attention by the German Army Command which so far had absolutely no interest in the Imperial German Navy, let alone U-boats, as suddenly possible contributions by U-boats to the overall military campaign in France and Belgium came up as a desire. However, the U-boats could never meet such desires, e.g. fighting the shipments across the English Channel of reinforcements and re-supplies for British expeditionary forces at the land front in France and Belgium. In fact, these were running almost without any threats from the sea. Interesting enough, fighting troop carrying vessels has not been part of any operational plan of U-boats at that time. Notwithstanding, on 27/ 28 Septembertember 1914 U 18 was the first of many more U-boats to come the pass through the barriers and guards of the English Channel at Dover-Calais. This became easier soon when German forces occupied the Belgian coast in November 1914.


KptLt Otto Hersing
KptLt (Lt.Cmdr.) Otto Hersing

Until the end of September 1914 German U-boats executed some 50 missions after all. In early October 1914 meanwhile 21 U-boats were available for the war at sea in the North Sea, besides the 12 older “Petroleum”(Kerosene)-U-boats already 9 of the new Diesel-U-boats with their much better seaworthiness. Between 10 and 20 October 1914 U 20 was the first German U-boat to circumnavigate the British Isle and Ireland, and on 20 October 1914 U 17 managed to sink off Stavanger the first merchant vessel in the war at sea, this strictly in compliance with the prize order. The U-boats enlarged their reconnaissance missions, now operating as far as the Belgian, French and British coasts along the entire British Channel. On 31 October 1914 U 27 managed to sink the British auxiliary aircraft carrier HMS Hermes off Calais. Finally, on 09 November 1914 it was U 12 to enter the port of Zeebrügge, Belgium, at the meanwhile German occupied Belgium coast, being the first German U-boat to do that – Zeebrügge then to become a German U-boat Base for the “Flandern”-Flotilla. In December 1914 activities by U-boats in the North Sea calmed down as the losses suffered so far required a certain consolidation of the U-boat force with regard to the availability of combat ready U-boats and crews. In his memories (see under literature) Wilhelm Bauer calls this period “economizing” of available forces.

SM U 9 (Pictures U-Boat Museum)

Generally, major successes were not achieved until the end of 1914. By the end of that year U-boats had managed to merely sink 3 merchant vessels totaling 2,950 GRT and 9 warships, but 5 own U-boats (U 13, U 15, U 11, U 18 and U 5) were lost, i.e. almost one fif the fleet of U-boats available in the North Sea at that time. With that, it was prudent to build on the proven value of U-boats in offensive missions and to seek for much more effective options in the war at sea, as the great and decisive sea battle between the German High Seas Fleet and British Grand Fleet hoped for would not occur, obviously. Moreover, the British distant blockade of the North Sea began to be felt in Germany with increasing effects. Therefore, the German strategic option to pursue was the “counter-blockade” and the “trade war” by U-boats. The latter meant, however, a political approval. Eventually, on 04 February 1915 the German Admiralty were allowed to lose the restrictions for the rules of engagements for the German U-boats for a first time when Germany declared the waters around Britain and Ireland, including the English Channel, as “area of warfare”. Even Grand Admiral von Tirpitz, the mastermind behind the buildup of the Imperial German Navy as a fleet of deterrence and, once challenged, seeking a decisive sea battle, in a surprise move changed his opinion, when he suddenly recognized a role for U-boats in the war at sea, upgrading them to be the most effective means of fighting the Royal Navy provided they were allowed to conduct a trade war with less restrictions. Consequently, on 18 February 1915 an “Order for the Trade War” approved U-boats of the Imperial German Navy to “conduct trade war energetically”, and to “sink enemy merchant shipping”, any reference to a prize order to be observed cannot be found in that order any longer.

KptLt Otto Weddigen
KptLt Otto Weddigen

What about the building program for U-boats during that period? Any speeding up of the ongoing building program until the end of 1914 was difficult since there were a number of organizational and manning problems: both Naval shipyards (Germania shipyard at Kiel and the Imperial shipyard at Danzig) were in full capacity managing the current building orders and the new orders for Uboats (Germania: on 04 August 1914 new building orders for U46 to U 50, and Danzig: on 23 August 1914 new building orders for U 51 to U 56), besides that all Naval shipyards were fully occupied to build and repair the large surface warships of the Imperial German Navy, i.e. there was simply nor more space at the shipyards available and no further workforce could be recruited. Therefore, the construction of Uboats was extended to be carried out even at other shipyards. On 06 October 1914 the Bremen based AG Weser shipyard received the building orders for U 57 to U 62. Also, building orders were given for smaller U-boats which could be constructed much faster (Total construction time: 4 months) than the previous ones. Hence, on 15 November 1914 the Germania shipyard got contracted to build UB 1 to UB 8 and the AG Weser received order to build UB 9 to UB 15. Another shipyard joined the family of U-boat constructors: On 23 November 1914 the Hamburg based Vulcan shipyard received building orders for smaller coastal Uboats for special minelaying missions, i.e. UC 1 to UC 10, whereas the AG Weser got additional orders for UC 11 to UC 15. (KptLt Otto Weddigen)

SM U 9 (Picture: U-Boat Museum)


No particular preparation or even pre-planned war deployments can be observed by the U-boat forces of the Imperial German Navy before the beginning of World War I, rather in contrast to the U-boats of the Kriegsmarine in World War II. Therefore, the theories developed by some historians about the war guilt of the German Reich leading to WW I are neither supported by activities of the U-boats of the Imperial German Navy nor the building program for U-boats. Consequently, any myths claiming differently can be done away as such.

There were some studies of the possible employment of U-boats on case of war against Britain, and mobilization plans were developed, which could by activated at the beginning of war. The war time mission planning immediately before the outbreak of war was carried out only in strict compliance with the rather defensively orientated mobilization plans, i.e. concentration on guard duties in the German Bight. A reason for that might have been that there actually were no firm ideas on what U-boats could offer in term of operational opportunities in a war at sea, since there were simply no experiences gained in combat at hand. The large scale reconnaissance missions to sweep the North Sea to the North by 9 U-boats ordered on 06 August 1914 as well as the sweep ordered on 08 August 1914 to the Eastern approaches of the English Channel by 4 U-boats were a first and soon diverging from original plans. It demonstrated the search by the U-boat Command for a best effective employment of U-boats.

The U-boat force did not play any significant role in the operational planning of the Imperial German Navy in case of war. U-boats were mainly to execute advanced defensive guard duties and targeted reconnaissance missions, any trade war only in strict adherence to the prize order. A most disadvantageous situation for the U-boat force was the lack of any uniform Naval leadership and the strong influence of politics with regard to the question of trade war, in addition the permanent interference of Emperor William II in all aspects of the employment of the Imperial German Navy.

At the beginning of war there was a first U-Flotilla formed by 14 U-boats (U 5 to U 18), however, employment of these U-boats in combat missions possible with limited effect only. The integration of new and more capable U-boats had just started, but just 4 U-boats of the second U-Flotilla were ready trained at the beginning of war. At this time, also the armament program for U-boats did not prove any particular effort for a war at sea with Britain. Even the only marginally enhanced building program for U-boats did not underline any significant shift in the overall building program for the Imperial German Navy at the benefit of U-boats, to be recognized soon as much more effective means of warfare at sea.

No systematic employment of U-boats can be observed during the first months of the war at sea. The focus of the missions was repeatedly changed and was ranging from almost stationary guard duties in the German Bight, to longer and more widespread reconnaissance sweeps searching for the Grand Fleet, up to targeted missions to establish counter-blockades by presence in selected sea areas. The rather soon amendment of combat missions for U-boats to include clearly offensive elements and the surprisingly great successes of individual U-boats against British warships during the first weeks of the war at sea led, on the other hand, slowly to a change in the assessment what U-boats can actually achieve in war. This change was very much supported by the absolute failure of any hope for a fast end of the war ashore, same as there was absolutely no great and decisive sea battle between the German High Seas Fleet and the British Grand Fleet in sight.

The trade war by U-boats, discussed so controversial by politics and international law, was a new phenomenon in the conduct of war at sea. However, it was the most effective means of warfare in the war at sea 1914-1918 in the later year, and it was the key campaign in World War II, all executed by U-boats. During the first months of the war at sea the U-boats of the Imperial German Navy were bound very much by guard duties and reconnaissance sweeps, while at the same time they were not able to fully employ their capabilities in the trade war against merchant shipping due to political constraints. Only later in war they were given freedom to demonstrate the decisive effect of this type of warfare.

The restrictive employment of trade war by U-boats during the early time of WW I as another means of conduction the war at sea and the permanent political interference in any use of it may be considered, on the other hand, as further argument in the discussion about the role of the German Reich before and at the beginning of WW I, since this type of warfare has been almost excluded from any utilization as strategic option before and during the first months of the war.

KTB von U 5 bis U 30

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


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