to aim for Jerusalem, in the hope of raising morale. By 18 April it was clear Nivelle's offensive had not succeeded, the newly democratic Russia could no longer be relied on to attack the German or Ottoman empires freeing them to reinforce Palestine and Mesopotamia, and the resumption of unrestricted German U-boat warfare was sinking 13 British ships a day when the average during 1916 had been only three. This misunderstanding of the actual position in southern Palestine "rest squarely on General Murray for, whether he intended it or not, the wording of the reports fully justifies the interpretation placed upon them." Second Battle of Gaza, 17–19 April The First Battle of Gaza had been fought by the mounted divisions during an "encounter battle" when speed and surprise were emphasised. Then Gaza had been an outpost garrisoned by a strong detachment on the flank of a line stretching eastwards from the Mediterranean Sea. During the three weeks between the First and Second Battles of Gaza, the town was quickly developed into the strongest point in a series of strongly entrenched positions extending to Hareira 12 miles (19 km) east of Gaza and south east towards Beersheba. The Ottoman defenders not only increased the width and depth of their front lines, they developed mutually supporting strong redoubts on ideal defensive ground. The construction of these defences changed the nature of the Second Battle of Gaza, fought from 17 to 19 April 1917, to an infantry frontal attack across open ground against well prepared entrenchments, with mounted troops in a supporting role. The infantry were strengthened by a detachment of eight Mark I tanks along with 4,000 rounds of 4.5-inch gas shells. The tanks were deployed along the front to give shelter to the infantry advancing behind them, but as the tanks became targets the infantry also suffered. Two tanks succeeded in reaching their objectives. Although the gas shells were fired during the first 40 minutes of the bombardment on a woodland area it appears they were ineffective. The strength of the Ottoman fortifications and the determination of their soldiers defeated the EEF. The EEF's strength, which before the two battles for Gaza could have supported an advance into Palestine, was now decimated. Murray commanding the EEF and Dobell commanding Eastern Force were relieved of their commands and sent back to England. Stalemate From April to October 1917 the Ottoman and British