A Survey of Ottoman Anti-Submarine Measures in the Dardanelles 1914-15
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1 A survey of Ottoman Anti-Submarine Measures in the Dardanelles 1914-15 By Harvey Broadbent, Senior Research Fellow in Modern History, Macquarie University. Paper delivered to the Kings Hall Naval Conference, Canberra, 22 May 2015 Background The Ottoman Empire entered the war on 31 October 1914 when Russia declared war on her after ships of the Ottoman navy, including the acquired old German cruisers Goeben (re- named the Yavuz) and Breslau (renamed the Midilli) gifted to Turkey, bombarded Russian Black Sea ports on 29 October (Sevastapol, Novorossisk, Feodosia, and Odessa). This was a pre-emptive strike, which had military and political strategic reasons behind it (which are not dealt with in this paper), and only minor damage was inflicted (on two small warships and six merchantmen). However, it was a success for Germany, as it propelled Russia to declare war on the Ottoman Empire and by 5 November, her allies Great Britain and France, too, were at war with what was left of the Ottoman Empire. The Ottoman Government had actually mobilised its armed forces on the outbreak of the European war in August and had gradually been drawn into the conflict by German machinations, internal Ottoman politics and British failures in diplomacy.1 Planning Ottoman defensive considerations during this period was something of a nightmare. By the nature of its geo-political position the Turks would have to defend at least four potential fronts—the Caucasus in the East, Sinai/Palestine and Suez in the south, together with the Mediterranean (e.g. Iskendurun/Alexandretta) and the Dardanelles Straits/Black Sea/ and Aegean approaches. Three of these became a reality-Caucasus, Suez-Sinai and of course the Dardanelles Strait. The Strait had always featured prominently in Ottoman defensive considerations and previous belligerent enemy states’ offensive considerations, especially since the British navy under Admiral Sir John Duckworth had penetrated to Istanbul (Constantinople) in 1804. So the Strait and its shores, the Gallipoli Peninsula and the Anatolian side as its guardian terrain, had to be secured. German naval assistance was sought from their naval mission, 1 Turkish General Staff, The History of the Turkish Armed Forces Ottoman Period, First World War, Volume V Book 1, The Dardanelles [Çanakkale]Front Operations. Turkish General Staff Publications, Ankara 1978. Referred to subsequently as TGSH History (Turkish General Staff History). p. 2 and Chapter 2 2 which had replaced Admiral Limpus’s British naval mission. 600 German defence specialists were sent, in attempted secret, to help the Ottomans on mine, gunnery, fortifications and torpedo warfare for the Dardanelles and the Bosphorus. At sea this meant laying a serious minefield and improving and updating shore fortifications.2 The Strait was only partially defended with laying of a cursory minefield and strengthening of the forts with their 12 and 15 inch cannons. Ottoman ships at this point needed to negotiate passage through the minefield and this was done by a pre-selected route (see Map 1).3 The British reply to the Ottoman fortification strengthening work, with German assistance, was a naval blockade of the Strait from the Aegean by their Mediterranean naval squadron, which began on 26 September 1914. In response, the Ottoman Government closed the Strait on 29 September. Now it was crucial to stop intruders and potential enemies from the south. On land to protect the shores, the 3rd Army Corps was initially deployed by 3 November and gradually reinforced until the Ottoman 5th Army was created in time for the Gallipoli Campaign in April 1915, putting 80, 000 or so troops to garrison the Peninsula. This military deployment corresponded with the first naval offensive activity. As 3rd Corps were settling their deployment on 3rd November 1914, British First Lord of the Admiralty, Winston Churchill, it seems, though records are not clear on this, had ordered the British Navy to bombard and try to reduce the outer forts of the Strait. In so doing the British issued a strong message to the Ottomans that the expected front at the Dardanelles was earmarked for operations.4 The intention of the attack was essentially to test the fortifications and measure the Ottoman response. The results were deceptively encouraging. In a 20-minute bombardment, a single shell struck the magazine of the fort at Seddulbahir at the tip of the Gallipoli peninsula, displacing (but not destroying) 10 guns and killing 86 Ottoman soldiers. Total casualties during the attack were 150, of which 40 were German. The most significant consequence was 2 Wolf, Klaus. Gallipoli 1915: Das Deutch-Türkische Militarbündnis im Ersten Weltkrieg, Report Verlag, Bonn, 2008. p.76ff 3 TGSH, Sketch (Kroki) C 4Rudenno, Victor. Gallipoli, Attack From the Sea, Yale University Press, Newhaven and London, 2008. p.27ff 3 that the attention of the Ottomans was drawn to strengthening their defences, and they set about expanding the mine field.5 People familiar with the Dardanelles Campaign are well aware that the first phase of Allied operations was to be purely naval, ending in failure to breach the Narrows on 18 March 1915. This paper is not concerned with the details of this action except to consider how the Strait’s defences were developed and how they were to impact on the operations of Allied submarines throughout 1915. Defence against attempts to force the Strait in 1915 Defence of the Strait was shared between Turkish and German commanders, Cevat Pasha, Turkish Commander of Strait’s Forts and Vice Admirals Guido von Usedom and his No. 2 Vice Admiral Merten. They were appointed by leader of the German Naval Mission, Admiral Souchon with the imprimatur of Enver Pasha, Ottoman War Minister and Deputy Commander-in-Chief to command all sea-based operations.6 This split command in the Strait was a manifestation of the Ottoman-German alliance and not always advantageous. A glance at the situation of the Strait’s defences on the 18 March, as the British and French Fleets assaulted, shows how far these defences had been developed since the outbreak of the war (see Map 2). The Strait is 35 miles from top to bottom. As a result of an appreciation, based on the November 1914 experience, that the vulnerability of the outer forts was not to be easily put right, Cevat developed a three sector defensive system. "Outer", "Intermediate" and "Inner", with the balance of defence strength being shifted to the Intermediate and Inner forts. The main foundation of the defence had to be the extended minefield, concentrated at the Narrows. This became well-known to the Allied fleet, especially as their minesweepers had failed and continued to fail to clear them. The British naval squadron’s use of North Sea Trawlers as minesweepers together with their civilian skippers is well recorded. There were 11 main lines laid across the Strait near the Narrows and containing a total of between 399 mines by 18 March, mainly German with some Russian ones retrieved from the Black Sea. Most were designed to withstand the strong current of the Strait.7 5 TGSH op. cit. Chapter 2 6 By historical precedent, the Ottoman Sultan, Mehmet V, held the title of Supreme Commander-in-Chief 7 TGSH op. cit. Chapter 2 4 A few days before 18 March, undetected by the British fleet and their aerial reconnaissance, the 11th line had been laid in Erenköy Bay under cover of night by the Nusret minelayer. This line caused the ultimate loss of the Bouvet and Inflexible. By December 1915 the number of lines was to be increased to 18 and the mines to 552. Mines in lines 1-10 were spaced 44 to 55 yards apart, and line 11 110 to 165 yards apart. The later lines 14 and 15 were comprised of two deep lines intended for destroying submarines. The Turks also had floating mines at their disposal—estimated at 50 in number. In addition to mines at the Narrows three 18 inch torpedo tubes were installed on the pier at Kilid Bahir, giving a point blank range field of fire across the Strait.8 The role of the forts was to protect the minefield from sweeping as much as bombarding warships. There was massive increase in numbers of guns on the forts and batteries. (see Map: Fields of Fire). The field of fire of the principal forts was below the minefields. Thus a barrage could be maintained on ships entering the Strait before they could reach the minefield to sweep them. Mobile artillery, mainly howitzers, 24 of them, were positioned along the both sides of the Strait. These were especially effective against the enemy minesweepers. They would move from one position to another, dragged by oxen teams to avoid the enemy getting a fix on them. Smoke canisters were used at various intervals to confuse the enemy gunners to draw fire away from the mobile batteries. It was the Ottoman tactic that the forts and batteries, mobile or fixed, protected the minefield. 70 guns and six searchlights protected the minefield at the Narrows. So searchlights played an important role in keeping the Strait defended at night. The further tactic was that these guns of the fixed and mobile batteries were protected by the large calibre guns of the forts, which in turn were protected from the enemy fleet by the mobile howitzers. These fired on the enemy ship to keep them moving so no concentration of fire onto the forts could be achieved, thus increasing inaccuracy. All these defences could be employed against submarines—the surface ones of course only seriously effective if and when a sub surfaces for any reason. When it came to underwater defences then more submarine-specific measures were necessary.