The artillery of the Odrin fortress



Bulgarian intelligence data of 1911 indicated that the fortress was armed with 192 heavy and 300 to 325 field guns. The exact figure was not known, but the Bulgarian Army thought that it might have exceeded 600 guns, counting also the field guns of the infantry divisions assigned to the Odrin garrison.


According with Bulgarian official history of the war there were :

         A] fixed guns

1 battery with 6 – 210mm L/10 mortars M. 1875 in coast carriage,

3 batteries with 19 – 150mm L/10 mortars M. 1875 in coast carriage,

1 batteries with 6 – 150mm L/26 long guns M. 1875,

2 batteries with 12 – 150mm L/20 short guns M. 1875,

11 batteries with 66 – 150mm L/26 fortress guns M. 1875,

6 batteries with 36 – 120mm L/25 long guns M. 1875,

2 batteries with 13 – 120mm short guns M. 1875,

6 batteries with 32 – 105mm L/35 long guns M. 1880,

35 batteries with 208 – 87mm L/24 field guns M. 1885,

1 battery with 1 – 75mm L/30 and 1 – 75mm L/28 anti-balloon quick-firing guns M. 1912,

5 fortress machine guns companies with 20 Maxim MG,

45 old Gatling machine guns.

         B] mobile guns

3 battery with 18 – 150mm L/14 quick-firing howitzers M. 1908,

1 batteries with 4 – 150mm mortars M. 1875,

1 battery with 6 – 120mm L/11.6 howitzers M. 1892,

1 battery with 12 – 120mm long guns M. 1875,

3 batteries with 18 – 105mm L/30 siege guns M. 1908,

3 batteries with 18 – 105mm howitzers M. 1905,

9 batteries with 36 – 75mm L/30 quick-firing field guns M. 1903,

1 battery with 4 – 75mm L/30 horse guns M. 1903,

1 battery with 6 – 75mm L/27 field guns M. 1885.


According with Turkish official history of the Balkan War on 1 October 1912 Turkish Army had in the whole fortified area :

12 – 75mm L/27 field guns,

176 – 87mm L/24 field guns,

12 – 105mm L/35 fortress guns,

36 - 120mm L/24 fortress guns

12 – 150mm L/14 (short) fortress guns,

78 – 150mm L/26 (long) fortress guns,

19 – 150mm L/6.4 mortars,

6 – 210mm L/6.4 mortars,

2 – 75mm anti-balloon quick-firing guns,

10  quick-firing Nordenfelt guns,

18 – 105mm L/30 quick-firing siege guns,

18 – 150mm L/14 quick-firing heavy howitzers.

Besides them there were the field guns of the Infantry Divisions assigned to the garrison: 36 – 75mm QF field guns, 8 – 75mm QF horse artillery guns, 6 – 120mm L/11 howitzers.


A large part of the guns came from Krupp factory. They used shells with a charge of black powder, mine-shells and shrapnel. In the ground the 210mm shells produced craters with a diameter of 4.5m in the clayey ground. The draught 105mm siege guns with a 9000m range proved to be very useful to the Turks; they shifted rapidly into the different Sectors and caused to the enemy considerable damages. With their shrapnel fire they fought successfully the aircrafts too. The fortress was well stocked with ammunition and provisions to enable it to withstand a prolonged siege and when the place surrendered, the Bulgarian Army found many full magazines.


The fortress had also a 750 cubic meters observation balloon arrived in April 1912, but it was not used during the siege, since there was not enough gas for it, and the crew lacked proper training and was unfamiliar with the launch and recovery procedures. Moreover there were no officers with proper training to command the ground crews or perform any useful aerial observation. On 6 November the balloon was damaged during an attempt to provide vital information for aiming the heavy artillery of the fortress. On 6 March 1913 another attempt met with failure since the balloon ascended only to a height of 15 meters, due to the insufficient amount of hydrogen gas.

At the beginning of the war a single seat 25 hp Deperdussin with its pilot, Refik, was loaded on a train and sent to Odrin. However the Bulgarian Army had moved so swiftly that it was routed back to Constantinople. In November another attempt to fly one aircraft to the fortress failed. On 17 February 1913 the fortress command was requested to prepare a landing ground for an aircraft that would fly in as soon as the weather permitted. Final preparations were made at a field already appropriated for this purpose near the ammunition depot, at the north side of town. But towards the end of February it became evident that an aircraft could not be delivered to Odrin, not only for the long distance, but also because there was no fuel, spare parts or other logistics available in the fortress to support its operation.


The fortress was originally equipped with 12 electrical searchlights with a diameter of 90cm, but during the Italian-Turkish War (1911-12) 7 of them were removed and sent to Istanbul and the Dardanelles. During the mobilization in September 1912, only 3 of them were returned. Their collocation is not sure, but probably they were placed at Aivas Baba, Kavkas Tabia, Taš Tabia in the Eastern Sector; at Karagφs Tabia and Kasan Tepe in North-western Sector; at Papas Tepe in Western Sector; at Karagač in Southern Sector; and on one of the four of minarets of the Sultan Selim mosque. In 1913 the Bulgarian Army captured 8 searchlights with a diameter of 90cm and 5 with a diameter of 60cm.