M15, M16, M17, M18 from 1915 Greek Navy Four guns of 45 calibres () bore produced by Elswick Ordnance Company were mounted in two twin turrets on the Greek cruiser Georgios Averof in 1910, instead of the guns mounted on her sisters of the Pisa-class in Italian service. These were similar to the four Vickers 45-calibre export model guns used by Britain as railway artillery on the Western Front in World War I under the designation BL 9.2-inch gun Mark XIV. They fired the same shell using the same cordite charge as the British service Mk X gun, and it may be assumed that its performance was very similar. British coastal deployments These were 'counter-bombardment' guns designed to defeat ships up to heavy cruisers armed with guns. They were deployed in the fixed defences of major defended ports throughout the British Empire until the 1950s. Their role was to defeat enemy ships attacking the ships in a port, including warships, alongside or at anchor in the port. However, where guns covered narrows, such as the Dover Straits, the Straits of Gibraltar, or the Narrows of Bermuda, they also had a wider role of engaging enemy ships passing through the straits. Normally deployed in batteries of two or three guns, a few major ports had several batteries positioned miles apart. There were several marks of mountings and a battery had extensive underground facilities in addition to the guns visible in their individual gun-pits. Together with the Mk VII, they provided the main heavy gun defence of the United Kingdom in World War I. Three Mk IX and 53 Mk X guns were in place as of April 1918. Mounting The Mounting Barbette Mark V (the original mounting with Mark IX and X guns) gave a maximum elevation of 15 degrees, and maximum range of . This and some modified to Mark VI (30 degrees and ) were manually powered, the projectile and propelling charge were manually hoisted to loading level, the projectile manually loaded and rammed, and traverse and elevation were by handwheels. There was an elevated platform around the breech area for the gun detachment commander (No 1) and some detachment members, and a Gun shield to the front. The ordnance and mounting together weighed some 125 tons, they were well balanced and the handwheels needed very little effort to move the gun. However, the Mark VII mounting appeared in