BL 18 Inch Mk I Naval Gun - Service

Service

A total of three guns were built by Armstrong Whitworth, two for Furious and a spare. The forward gun was removed from Furious in March 1917, before she was completed, when she was ordered to be converted to a seaplane carrier. The second gun was removed later in 1917, and she was converted into an aircraft carrier. The new 'B CD' mounts were delayed, and the mount for Lord Clive-class monitor General Wolfe was not delivered until 20 June 1918. The gun from Furious' 'A' turret was lifted aboard on 9 July, but the General Wolfe was not ready to begin firing trials until 7 August. She was given the nickname of 'Elephant and Castle', as the enormous gun-mount structure dominated the ship's profile.

While the new mounting was being designed, further effort was put into the ammunition to extend the range as much as possible. Use of a supercharge, where one of the six charges was increased in weight to 165 pounds (74.8 kg), making a total of 690 pounds (313.0 kg) propellant, and increasing the elevation to 45° extended the range to about 36,900 yards (33,700 m) with the existing 4crh shells. New 8crh high explosive shells, with a longer, thinner ballistic cap, were ordered, but only two shells had been delivered before the end of the war. Some of the existing stock of 500 APC and 500 CPC (common, pointed, capped) shells on hand from Furious were modified with the new cap and were probably the only shells used during the war.

The General Wolfe was assigned to the Dover Patrol on 15 August, but did not fire on any targets until 28 September, when a large force of monitors was gathered to harass German lines of communication. She was anchored bow and stern, broadside to her target, and had difficulties dealing with the tidal currents. She opened fire on the railway bridge at Snaeskerke (4 miles (6.4 km) south of Ostend) at a range of 36,000 yards (32,918 m) and made naval history as the heaviest shell fired from the largest gun at the longest range in action to date. She fired 52 shells that day and found that the recoil from her 18–inch gun moved her sideways with her shallow hull and also caused her to roll, which slowed her rate of fire. She fired a total of 81 rounds before the end of the war.

The second gun, Furious' spare, was mounted in Lord Clive, but she was not ready for combat until 13 October. She fired three rounds the following day, but had to cease fire to avoid hitting friendly advancing troops. One round had already been loaded when the order came to cease fire so she fired it, with a reduced charge, into a minefield to seaward. A total of 85 18-inch shells were fired in action by both guns.

The third gun, from Furious' 'Y' turret, was intended for Prince Eugene, which had been modified to accept it earlier in the year, but the war ended before it was mounted, although the monitor was ordered to Portsmouth to have it fitted on 19 October. The guns were removed from the monitors in December 1920. Gun No. 1, from Furious' 'Y' turret, was lined down to 16 inches (410 mm) and used in cordite-proving tests for the BL 16-inch Mk I gun, intended for the cancelled G3 battlecruisers, and used in the Nelson-class battleships. It remained in use until 1942 and was scrapped in 1947. The other two guns were used at Shoeburyness and Yantlet artillery ranges in the Thames Estuary for similar duties; they were scrapped in 1933.

One mount survived and was used to mount a spare BL 14-inch Mk VII gun from the battleship HMS King George V (41). It was emplaced near Dover in 1940, and the combination was named "Pooh", after Winnie-the-Pooh.