The German and the Austro-Hungarian submarines in the eastern Mediterranean during 1916
S.M.S. Goeben and S.M.S. Breslau.
The beginning of the war in the eastern Mediterranean.
Immediately after the war’s outbreak in August 1914, two German warships, the S.M.S. Goeben and S.M.S. Breslau, which made up the Mediterranean Naval Division (Mittelmeerdivision) of the German Imperial Navy (Kaiserliche Deutsche Marine) commanded by Vice Admiral Wilhelm Souchon, bombarded the Algerian ports of Bône and Philippeville aiming to stop troop transfers of the French colonial army to mainland France. After an order issued by the First Lord of the Admiralty Winston Churchill, the British fleet under the command of Admiral Sir Berkley Milne was in control of the entire Mediterranean Sea, began a ruthless pursuit targeted at sinking the Goeben and Breslau. Successfully evading the Entente fleet, with the exception of one sea battle against the British ship HMS Gloucester, Souchon managed to reach the Strait of Dardanelles where after agreements among Germany and the Ottoman Government, he willingly turned his ships over to the Ottoman Navy.
Soon afterwards, the ships’ names were changed from S.M.S. Goeben and S.M.S. Breslau to Yavuz Sulltan Selim and Midilli (Mytilene) respectively, while the crew remained predominantly German but wore distinctive Ottoman Navy insignia. The command of the ships remained under Wilhelm Souchon, who for that matter was also given the honor of becoming Ottoman Navy’s Admiral. On 29th and 30th October 1914 these two ships, sailing under the Ottoman flag, bombed the Russian Naval Bases at Sevastopol and Odessa. These attacks had led to Russia’s declaration of war against the Ottoman Empire on November 2nd 1914 and consequently to Ottomans’ declaration of war against the Entante on November 12th of the same year.
The closure of the Straits of Dardanelles and Bosporus from the combined Central Powers, – consisting of Austria-Hungary, Germany, the Ottoman Empire and later Bulgaria (14.10.1915) – as well as the simultaneous control of the Baltic Sea by the German Imperial Fleet, led not only to the blockade of the Imperial Russian Navy at the Black Sea, but also to the inaccessibility of all marine routes which would unite the forces of the Entente with their ally, Russia, who at the same time was the main wheat provider for France and Britain. This fact, coupled with the stabilization of the western front in northern France, led Britain and France to organize and carry out a campaign aimed at opening up the Dardanelles and conquering Constantinople.
Following the gathering of Entente’s naval forces just outside the Hellespont on March 18th 1915, the first battle attempting to seize the Dardanelles was fought but the operation failed. Subsequently on April 25th 1915, five Ally divisions consisting of more than 75,000 men landed on the shores of the Gallipoli peninsula. This was the beginning of the Dardanelles Campaign or as it is better known the Gallipoli Campaign, which during the one year that it was fought would cost more than 250,000 lives from both warring sides.
The German submarine U 21
At the height of the Dardanelles campaign, combined by the great pressure from the Entente’s warships which had ceaselessly been bombing the Turkish defense positions at the Hellespont, pushed the German Admiralty (Deutscher Admiralstab) to decide the dispatch of submarine aid to the Dardanelles defense, since previously had been quite successful at submarine warfare in the North Sea and the Atlantic Ocean. The submarine they sent to the Dardanelles was the U 21, commanded by the experienced Lieutenant Commander Otto Hersing.
On April 25th 1915, U 21, which was the first submarine to sink an enemy ship (HMS Pathfinder) by a torpedo, had sailed from its base in Wilhelmshaven towards the Mediterranean. After several setbacks, the submarine finally arrived at the Austro-Hungarian naval base of Cattaro at the Adriatic Sea, with in its tanks only 1.8 tonnes of fuel remaining. On May 20th 1915, U 21 embarked on its first Mediterranean mission out of Cattaro, aiming to break through the Dardanelles and thus support the Central Powers and especially the Ottoman defense units.
On 25th May 1915, the U 21 facing Entente’s fleet right in front of the Dardanelles entrance, sunk by torpedo the British battleship HMS Triumph (11.985 GRT). Two days later, on May 27th, outside the Cape Elli, a second British battleship was sunk, HMS Majestic (14.900 GRT), despite being protected by a grid made up of smaller vessels. After breaking the Entente’s naval blockade, U21 crossed the Dardanelles and the Sea of Marmara, finally arriving at Istanbul (Constantinople) and joining Admiral Souchon’s fleet on June, 5th 1915.
This success of Otto Hersing, who was awarded the highest military medal for his achievements, the Pour le Merité, better known as the Blauer Max (Blue Max), led the Admiralstab to reassess its submarine warfare strategy in the Mediterranean. The resulting decision was the establishment of a submarine flotilla which would engage against Entente’s ships, based in the Austrian-Hungary ports of Pola at Istria and Cattaro at Dalmatia. Initially the German Admiralty sent by train eight UB and UC class disassembled submarines which were reassembled in Pola. In August of the same year, the submarines U 34 (Kapitänleutnant Claus Rücker), U 35 (Kapitänleutnant Waldemar Kophamel), U 39 (Kapitänleutnant Walter Forstmann) and U 33 (Kapitänleutnant Konrad Gansser), received the order to set course for the Mediterranean. The main reason for this relocation was in one hand the strengthening of the defenses at Dardanelles, through the action of submarines against the Entente fleets and on the other hand the political situation which had led to restrictions of submarine warfare around England and Ireland, resulting in an increased unneeded submarines in that region.
With the arrival of these submarines at Pola and of the others which had been sent by train, the basis was set for the creation of the German Mediterranean Submarine Flotilla, known as the Deutsche U-Flottille Pola.
Deutsche U-Flottille Pola
The Deutsche U-Flottille Pola (former U-Halbflottille) was officially created on 18th November 1915, with Waldemar Kophamel as its commander, who was promoted to Korvettenkapitän. This submarine flotilla destined to play an important role in the outcome of the war, presenting to the Admiralstab the opportunity to advantageously redistribute the naval power in the Mediterranean Sea. Although its original purpose, as already mentioned, was to support the defense of the Central Powers in the Dardanelles, it very quickly became obvious that there was a possibility of engaging the so-called «commerce raiding», with the objective to economically weaken the Entente member countries. This type of warfare was regulated by international law which was agreed by the 1909 International London Convention.
During late 1915 and throughout 1916 commerce raiding was being carried on according to the “prize rules”, with only a few exceptions. The “Unrestricted Submarine Warfare” followed in 1917 after America’s joining the Entente forces on 2.4.1917. In 1916 the German diplomacy was still fighting to keep America firmly neutral. Any action which could potentially provoke the American public was seen as an act against German interests. By transferring the commerce raiding to the Mediterranean, apart from carrying out hostile attacks against the enemy navies, German submarines would find rich pillage on British and French merchant vessels with little probability of American citizens being on board, hence was a project which the Admiralstab enthusiastically set as its strategic goal. Very swiftly the number of the submarines comprising the flotilla began to rise, reaching to 40 subs by the end of 1916.
The submarines of Deutsche U-Flottille Pola and their “mother ship” (Mutterschiff) S.M.S. Gäa, based in Pola and Cattaro, cruised throughout the Mediterranean and part of the Atlantic outside Gibraltar. Although Entente’s naval forces had positioned a large number of ships equipped with anti-submarine nets in the Strait of Otranto, known as the Otranto Barrage, German submarines passed through almost uninterruptedly to carry out their missions. At the same time, the continuous production of submarines by German shipyards combined with the enormous potential of the new weapon, which was unparalleled at the time, led very quickly to a shift in the balance of naval powers in favor of Germany.
Since the formation of Deutsche U-Flottille Pola in August 1916, German submarines operated in the Adriatic flying the Austrian-Hungarian Navy flag, known as K.u.K. Marine from short of “Kaiserliche und Königliche Marine” or Imperial and Royal Navy, a name which conveyed the double identity of the Empire, i.e. the Austrian and the Hungarian. The reason for not flying the German Navy flag was due to the fact that Italy had not as yet declared war against Germany. Such was declared on 28th August 1916.
The dominance of German subs in the Mediterranean combined with countless naval operations, punctuated the technical superiority of this new weapon and highlighted the achievements of a number of captains who were referred as the “Aces” of submarine warfare. Many of them were praised not only by their crews, but also by their opponents because of their integrity and adherence to the rules of sea warfare. Among them Lothar von Arnauld de la Perière was considered as the very best, who within only four months from April to August 1916 had managed to sink 77 ships totaling 160,000 GRT. For such an achievement he deployed only four torpedoes, one even having missed its target. It was a considered as a matter of honor for German submarine commanders, to sink their enemy targets on the surface by cannon fire instead of torpedoing.
Deutsche U-Flottille Pola consisted of quite few different U boat classes. Among them, the key ones, out of 23 different German sub classes, were the U 19, U 31, U 43, U 51, U 63, UB II and the mine laying UC I (restricted operational range) and UE1 (extended operational range). To the UE1 class belonging to U-Flottile Pola were the U 72 and U 73 subs. The latter is considered responsible for the sinking of both S/S Burdigala and HMHS Britannic in the Kea Channel, as a result of striking mines of minefield number 32, having been laid on 28th October 1916.
The Austria-Hungary submarines of K.u.K. Marine
The Austia-Hungary Navy, better known as K.u.K Marine – which after the war ended ceased its operations due to the collapse of the Austria-Hungary Empire but also due to the loss of the coastal areas of Istria, Croatia and Dalmatia eliminating access to the Adriatic Sea, – listed in 1909 the sub S.M. Unterseeboot III (later U 3) in its fleet. This marked the formation of the K.u.K. Unterseeboote – Flottille Pola supported by “mother ship” S.M.S. Pelikan. This flotilla increased to six subs by 1912.
With Austria-Hungary’s declaration of war against Serbia, on 28th July 1914, and the deployment of K.u.K Marine in the Adriatic, the flotilla was strengthened by five German UB I class subs and by an additional foursome (Unterseeboote 20, 21, 22, 23) built by the Austria-Hungary shipyards of Fiume and Pola.
The K.u.K. flotilla commanded by Franz Ritter von Thierry, operated mainly in the Adriatic and seldom ventured south of Ortanto. Two reasons limited its operational range, the small size of the subs, capable of few day missions, and their small numbers. Even though the K.u.K. sub flotilla did not match the achievements of Deutsche U-Flottille Pola, had several successes among which the sinking of the French Battleship F/S Léon Gambetta on 27th April 1915, by the U 5 commanded by Georg Ritter von Trapp, and the sinking of Italian cargo ship Milazzo on 29th August 1917, by the U 14 (ex French sub Curie), commanded also by von Trapp.
Another notable success of K.u.K. Unterseeboote – Flottille Pola, which did not conclude in the sinking of the French Courbet class flag ship F/S Jean Bart on 21st September 1914, by the U 12 near Otranto.
Thessaloniki during the Macedonian Front
After the Entente’s failure to conquer the Dardanelles and the stalemate at the Gallipoli peninsula, the Bulgarian army, an ally of the German Central Power, attacked Serbia in October 1915. This new threat forced Serbia to seek immediate support from its ally Greece. The Greek Prime Minister Eleftherios Venizelos who was a supporter of the Entente, suggested the dispatching of British and French troops to Thessaloniki and from there their advancement to the Bardar valley to assist the Serbs. At the same time he guaranteed the missions support by Greek King Constantine, who was of German descent and fiercely against the prospect of Greece’s entering the war.
Even though Entente’s request was not approved by the King and his staff, on 3rd October 1915, a British and a French army division landed on Thessaloniki port which later became not only Entente’s military base during the so called Macedonian Front, but also the base of the Provisional Greek Government of “National Defense” after the armed protest of Athens on 13th September 1916.
Thessaloniki, having a population of 165,704 in 1916 consisting of 45% Greeks, 37% Jews and 18% Muslims, became within a short time the center for thousends of soldiers and tons of war materiel, transported by British and French ships from the various allied ports. Entente’s warships and troop transports thus became prime alternative targets for the German subs engaged at the height of “commerce raiding” in the Mediterranean Sea. The Admiralstab was aware of their sea routes and deployed in addition to standard submarines, special mine laying ones for positioning minefields at strategic passages. From November 1915 to January 1917, 45 minefields were laid in the Med and the Black Sea, causing a heavy toll to shipping under neutral and enemy flags alike. Among the casualties were ships being under the protection established by the “war rules” agreed by the enemies, as for example Hospital Ships. The most notable among these was the sinking of HMHS Britannic on 21st November 1916 in the Kea Cahannel (minefield Nr. 32) and of HMHS HMHS Braemer Castle, which was beached after striking a mine on 23rd November 1916 in the Tenos-Mykonos straits (minefiled Nr. 33). These minefields were deployed by the German sub U 73 (commanded by Kapitänleutnant Gustav Siess), which is also believed to be responsible for the sinking of S/S Burdigala on 14th November 1916 in the Kea Channel, less than two miles away from the HMHS Britannic shipwreck.