On 27 October 1914, two formerly German warships, now the Ottoman Yavûz Sultân Selîm and Midilli, still under German officers, conducted the Black Sea Raid, in which they bombarded the Russian port of Odessa and sank several ships. In early November the various powers declared war. Turkey opened the Caucasus Campaign against Russia. The British briefly bombarded forts in Gallipoli, began the Mesopotamian Campaign, and studied the possibility of forcing the Dardanelles.
Allied strategy and the Dardanelles
Sea access to Russia through the Dardanelles (in yellow)
Before the Dardanelles operation was conceived, the British had planned to conduct an amphibious invasion near Alexandretta on the Mediterranean, an idea originally presented by Boghos Nubar in 1914. This plan was developed by the Secretary of State for War, Field Marshal Earl Kitchener to sever the capital from Syria, Palestine and Egypt. Alexandretta was an area with a Christian population and was the strategic centre of the Empire's railway network—its capture would have cut the empire in two. Vice Admiral Sir Richard Peirse, East Indies Station, ordered Captain Frank Larkin of HMS Doris to Alexandretta on 13 December 1914. At the same time, in the same area, the Russian cruiser Askold and the French cruiser
were performing similar operations. Kitchener was working on the plan as late as March 1915. This plan was also the beginning of Britain's successful effort to start an Arab Revolt. The Alexandretta landing was abandoned because militarily it would have required more resources than France could allocate and politically France did not want the British operating in their sphere of influence, a position to which Britain had agreed in 1912.
By late 1914 the war on the Western Front had become a stalemate; the Franco-British counter-offensive of the First Battle of the Marne had ended and the British had suffered many casualties in the First Battle of Ypres in Flanders. The war of manoeuvre ended and trench warfare began. The German Empire and Austria-Hungary closed the overland trade routes between Britain and France in the west and Russia in the east. The White Sea in the arctic north and the Sea of Okhotsk in the Far East were icebound in winter and distant from the Eastern Front, the Baltic Sea was blockaded by the Kaiserliche Marine (Imperial German Navy) and the entrance to the Black Sea through the Dardanelles was controlled by the Ottoman Empire. While the empire remained neutral supplies could still be sent to Russia through the Dardanelles but prior to the Ottoman entry into the war the straits had been closed and in November they began to mine the waterway.
French Minister of Justice Aristide Briand's proposal in November to attack the Ottoman Empire was rejected and an attempt by the British to pay the Ottomans to join the Allied side also failed. Later that month, Winston Churchill, First Lord of the Admiralty, proposed a naval attack on the Dardanelles, based in part on erroneous reports of Ottoman troop strength. Churchill wanted to use a large number of obsolete battleships, which could not operate against the German High Seas Fleet, in a Dardanelles operation, with a small occupation force provided by the army. It was hoped that an attack on the Ottomans would also draw Bulgaria and Greece (both formerly ruled by the Ottomans) into the war on the Allied side. On 2 January 1915, Grand Duke Nicholas of Russia appealed successfully to Britain for assistance against the Ottomans, who were conducting an offensive in the Caucasus. Planning began for a naval demonstration in the Dardanelles to divert troops from the Caucasian theatre of operations.