 The Germans and Austro @-@ Hungarians wanted to transport munitions down the Danube to the Ottoman Empire , so on 24 December 1914 , Bodrog and the minesweeper Almos escorted the steamer <unk> loaded with munitions , the patrol boat b and two tugs from Zemun past Belgrade towards the Iron Gates gorge on the Serbian – Romanian border . The convoy ran the gauntlet of the Belgrade defences unharmed , but when it reached Smederevo it received information that the Russians had established a minefield and log barrier just south of the Iron Gates . It turned back under heavy fire , and withdrew as far as Pančevo without serious damage to any vessel . Bodrog returned to base , and the monitor SMS Inn was sent to guard the munitions and escort the convoy back to Petrovaradin . In January 1915 , British artillery arrived in Belgrade , further bolstering its defences , and Bodrog spent the first months of the year at Zemun . On 23 February , LSL <unk> Böhm took command . On 1 March , Bodrog and several other vessels including the monitor SMS Körös were relocated to Petrovaradin . After the commencement of the Gallipoli campaign , munitions supply to the Ottomans became critical , so another attempt was planned . On 30 March , the steamer Belgrad left Zemun , escorted by Bodrog and Enns . The convoy was undetected as it sailed past Belgrade at night during a storm , but after the monitors returned to base , Belgrad struck a mine near Vinča , and after coming under heavy artillery fire , exploded near Ritopek . On 22 April 1915 , a British picket boat that had been brought overland by rail from Salonika was used to attack the Danube Flotilla anchorage at Zemun , firing two torpedoes without success . 
