Barrington and Eastney, weighed about 15 tons each, and Kerr had neither the knowledge nor machinery to move them. Fortunately a specialist team run by Commander William G. H. Bickford DSO (1869–1932) was available put the guns in place. One of the targets chosen by the French artillery staff officer was two German 11 inch howitzers sited four miles away. For about a year periodic exchanges of fire took place between the howitzers and the British guns. If an incoming shell landed on or near the bunker, the sandbags provided protection but the explosion reduced their number, so frantic efforts to replace these took place during the lull in the bombardments. A second battery of two 9.2 inch guns was added towards the end of 1916. This was named Carnac and sited about 1000 yards to the rear of Barrington and Eastney; the officer put in charge of Carnac was Jameson Adams, the Antarctic explorer whose wife was Phoebe Carnac Thompson Fisher. In late February 1917 a German howitzer shell struck Barrington's gun port – the most vulnerable part of the bunker – and destroyed the gun. There was only one, minor, casualty and the gun was replaced by early April. In December 1917 Barrington succumbed to a five-day relentless bombardment from the German howitzer which damaged the bunker beyond repair. About this time the Royal Marine Artillery took over the batteries at Lewin, and Kerr was transferred to Egypt. In 1917 the Croix de Guerre was conferred on Kerr by the President of the French Republic. Port convoy officer Initially Kerr had received orders to report to Rear Admiral commanding the British Adriatic Squadron and take over the role of Port Convoy Officer (PCO) in Taranto, Italy. Within two days of his arrival the orders had changed; he was instructed to report to Malta and told he would now be the PCO in Port Said, Egypt with rank of acting commander. The convoy system had evolved to counter the threat from submarine warfare. Merchant ships gathered together in Port Said and were escorted to their destination by warships or armed merchantmen. Other counter measures included mine sweeping and the use of seaplanes to hunt for enemy submarines. Intelligence gathering also identified where submarines may be operating so that convoys could be routed around these zones. Kerr's section co-ordinated the movement of 301 convoys between the date of his appointment