The naval operations in the Dardanelles campaign (17 February 1915 – 9 January 1916) took place against the Ottoman Empire during the First World War. Ships of the Royal Navy, French Marine nationale, Imperial Russian Navy (Российский императорский флот) and the Royal Australian Navy, attempted to force a passage through the Dardanelles Straits, a narrow, 41-mile-long (66 km) waterway connecting the Mediterranean Sea with the Sea of Marmara and the Black Sea further north.
The naval operations were defeated by the Ottoman defenders, mainly through use of naval mines. The Allies conducted the Gallipoli campaign, a land invasion of the Gallipoli peninsula to eliminate the Ottoman artillery along the straits before resuming naval operations. The Allies also passed submarines through the Dardanelles to attack Ottoman shipping in the Sea of Marmara.
Background
Dardanelles Strait
The mouth of the strait is 2.3 mi (3.7 km) wide with a rapid current emptying from the Black Sea into the Aegean. The distance from Cape Helles to the Sea of Marmara is about 41 mi (66 km), overlooked by the heights on the Gallipoli peninsula and lower hills on the Asiatic shore. The passage widens for 5 mi (8.0 km) to Eren Keui Bay, the widest point of the strait at 4.5 mi (7.2 km), then narrows for 11 mi (18 km) to Kephez Point, where the waterway is 1.75 mi (2.82 km) wide and then broadens as far as Sari Sighlar Bay. The narrowest part of the strait is 14 mi (23 km) upstream, from Chanak to Kilid Bahr at 1,600 yd (1,500 m), where the channel turns north and widens for 4 mi (6.4 km) to Nagara Point.
From the point, the passage turns north-east for the final 23 mi (37 km) to the Sea of Marmara. The Ottomans used the term "fortress" to describe the sea defences of the Dardanelles on both sides of the waterway from the Aegean approaches to Chanak. In 1914 only the defences from the entrance of the straits and 4 mi (6.4 km) from the north end of Kephez Bay to Chanak had been fortified. Until late October 1914, the nature of the seaward defences of the Dardanelles was known to the British and French but after hostilities commenced, information on improvements to the Ottoman fortifications became harder to obtain.
Ottoman entry into the war
At the beginning of the 20th century, the Ottoman Empire had a reputation as the sick man of Europe. After the Balkan Wars of 1912 and 1913, the French, British and Germans had offered financial aid. In December 1913, the Germans sent a military mission to Constantinople, headed by General Otto Liman von Sanders. The geographical position of the Ottoman Empire meant that Russia, France and Britain had a significant interest in Ottoman neutrality. During the Sarajevo Crisis in 1914, German diplomats offered Turkey an anti-Russian alliance and territorial gains, when the pro-British faction in the Cabinet was isolated, due to the British ambassador's absence. On 30 July 1914, two days after the outbreak of the war in Europe, the Ottoman leaders, unaware that the British might enter a European war, agreed to a secret Ottoman-German Alliance against Russia, although it did not require them to undertake military action.
On 2 August, the British requisitioned the modern battleships Sultân Osmân-ı Evvel and Reşadiye which British shipyards had been building for the Ottoman Navy, alienating pro-British elements. The German government offered SMS Goeben and SMS Breslau as replacements. In the Pursuit of Goeben and Breslau, the ships escaped when the Ottoman government opened the Dardanelles to them, despite international law requiring a neutral party to block military shipping. In September, the British naval mission to the Ottomans was recalled and Rear Admiral Wilhelm Souchon of the Imperial German Navy took command of the Ottoman navy. The German naval presence, and the success of the German armies, gave the pro-German faction in the Ottoman government enough influence to declare war on Russia.
Closure of the Dardanelles
In October 1914, following an incident on 27 September, when the British Dardanelles squadron had seized an Ottoman torpedo boat, the German commander of the Dardanelles fortifications ordered the passage closed, adding to the impression that the Ottomans were pro-German. Hostilities began on 28 October, when the Ottoman fleet, including Goeben and Breslau (flying the Ottoman flag and renamed Yavûz Sultân Selîm and Midilli but still commanded by German officers and manned by German crews) conducted the Black Sea Raid. Odessa and Sevastopol were bombarded, and a Russian minelayer and gunboat were sunk. The Ottomans refused an Allied demand that they expel the German missions and on 31 October 1914, formally joined the Central Powers. Russia declared war on the Ottoman Empire on 2 November and the British ambassador left Constantinople the next day.
A British naval squadron bombarded the Dardanelles outer defensive forts at Kum Kale and Seddulbahir; a shell hit a magazine and the explosion knocked the guns off their mounts and killed 86 soldiers. Britain and France declared war on Turkey on 5 November and the Ottomans declared a jihad (holy war) later that month. The Caucasus campaign, an Ottoman attack on Russia through the Caucasus Mountains began in December, leading the Russians to call for aid from Britain in January 1915. The Mesopotamian campaign began with a British landing to occupy the oil facilities in the Persian Gulf. The Ottomans prepared to attack Egypt in early 1915, to occupy the Suez Canal and cut the Mediterranean route to British India and the Far East.
Prelude
Allied strategy
Field Marshal Lord Kitchener planned an amphibious landing near Alexandretta in Syria in 1914, to sever the capital from Syria, Palestine and Egypt. Vice Admiral Sir Richard Peirse, Commander-in-Chief, East Indies, ordered HMS Doris to Alexandretta on 13 December 1914 as the Russian cruiser Askold and the French cruiser Requin were performing similar operations. The Alexandretta landing was abandoned because it required more resources than France could allocate; 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, static warfare had begun on the Western Front, with no prospect of a quick decisive victory and the Central Powers had closed the overland trade routes between Britain, France and Russia. The White Sea in the Arctic and the Sea of Okhotsk in the Far East were icebound in winter and the Baltic Sea was blockaded by the Kaiserliche Marine (Imperial German Navy). Ottoman belligerence closed the Dardanelles, the remaining supply route to Russia.
In November 1914, the French Minister, Aristide Briand, proposed an attack on the Ottoman Empire but the idea was rejected and an attempt by the British to buy off the Ottomans also failed. On 2 January 1915, Grand Duke Nicholas of Russia appealed to Britain for assistance against the Ottoman Erzurum Offensive in the Caucasus and planning began for a naval demonstration in the Dardanelles, as a diversion. Winston Churchill, the First Lord of the Admiralty, proposed an invasion of Schleswig-Holstein by sea, drawing Denmark into the war and re-opening the Baltic Sea route to Russia and an attack on the Dardanelles, to control the Mediterranean-Black Sea supply route and to encourage Bulgaria and Romania to join the Allies. The urgency of the Russian appeal and disdain for the military power of the Ottoman Empire made a campaign in the Dardanelles appear feasible.
On 11 January 1915, the commander of the British Mediterranean Squadron, Vice Admiral Sackville Carden proposed a plan for forcing the Dardanelles using battleships, submarines and minesweepers. On 13 February, the British War Council approved the plan and Carden was given more pre-dreadnought battleships, the modern battleship HMS Queen Elizabeth and the battlecruiser HMS Inflexible. France contributed a squadron including four pre-dreadnoughts and the Russian navy provided the light cruiser Askold. In early February 1915, the naval forces were supplemented by contingents of Royal Marines and the 29th Division, the last uncommitted regular division, which joined Australian and New Zealand Army Corps (Anzac) divisions training in Egypt. The infantry were intended for the occupation of Constantinople after the straits had been taken by the Entente navies.
Dardanelles defences
In August 1914, the Outer Defences were two fortresses at the end of the Gallipoli peninsula and two on the Asiatic shore. The forts had 19 guns, four with a range of 9 mi (14 km) and the remainder with ranges of 3.4–4.5 mi (5.5–7.2 km). Four field howitzers were dug in at Tekke Burnu (Cape Tekke) on the European side, then for the next 10 mi (16 km), there was a gap until the Intermediate Defences at Kephez Point, with four defensive works on the south shore and one on the north shore. The fortresses had been built to cover a minefield, which in August 1914 was a line of mines across the strait from Kephez Point to the European shore. Fort Dardanos was the main work which had two new 6-inch naval guns and the rest contained ten small quick-firing guns with shields. At the Narrows, the Inner Defences had the heaviest guns and some mobile light howitzers and field guns. Five forts had been built on the European side and six on the Asian side with 72 heavy and medium guns. Most of the artillery was obsolescent but there were five long-range 14 in (360 mm) guns with a range of 9.7 mi (15.6 km) and three 9.4 in (240 mm) guns with a 8.5 mi (13.7 km) range. The remainder of the guns in the Inner Defences were mostly obsolete and unable to shoot beyond 5.7 mi (9.2 km).
Of the 100 guns in the pre-war defences, only 14 were modern long-range pieces, the rest being old-fashioned breech loaders on fixed carriages. The gunners were poorly trained, there was little ammunition and scant prospect of replacement. Night illumination consisted of a searchlight at entrance to the Straits and one at the Narrows. The forts were easily visible, there were few gun shields and other protective features for the gun-crews and range-finding, artillery observation and fire-control depended on an telephones linked by wire on telephone poles, vulnerable to artillery-fire. The Ottoman official historian wrote,
On mobilisation, the fortification and armament of the Dardanelles was very inadequate. Not only were the majority of the guns of old pattern, with a slow rate of fire and short range, but their ammunition supply was also limited.
— Ottoman Official History
Ottoman strategy
The Germans secured the appointment of Lieutenant-General Erich Weber as an advisor to the Ottoman GHQ and at the end of August 1914, Vice-Admiral Guido von Usedom, several specialists and 500 men were sent to reinforce the forts on the Dardanelles and Bosphorus. In September, Usedom was made Inspector-General of Coast Defences and Mines and Vice-Admiral Johannes Merten relieved Weber at Chanak with a marine detachment to operate the modern guns. By mid-September, the German advisers reported that the guns in the Narrows had been refurbished and were serviceable. By October, most of the guns in the main batteries had German crews, operating as training units but able to man the guns in an emergency. Plans were made to build more defensive works in the Intermediate Zone and to bring in mobile howitzers and quick-firers dismounted from older Ottoman ships. Several heavy howitzers arrived in October but the poor standard of training of the Ottoman gunners, obsolete armaments and the chronic ammunition shortage, which Usedom reported was sufficient only to defend against one serious attack, led him to base the defence of the straits on minefields.