The BL 18-inch Mk I naval gun was a breech-loadingnaval rifle used by the Royal Navy during World War I. It was the largest and heaviest gun ever used by the British.[1] Only the Second-World-War Japanese 46 cm/45 Type 94 had a larger calibre, 18.1 inches (46cm), and it fired a lighter shell. The gun was a scaled-up version of the BL 15 inch Mk I naval gun and was developed to equip the "large light cruiser" (a form of battlecruiser) Furious. Its barrel length of 60ft (18m) was just 40 calibres, slightly limiting its muzzle velocity.
Only three guns were built, but they did not see combat with Furious before they were removed from her and transferred to the Lord Clive-classmonitorsGeneral Wolfe and Lord Clive for coast-bombardment duties. Only 85 rounds were fired in combat operations before the war ended. All three were removed from service in 1920 and served as proving guns for cordite tests. Two were scrapped in 1933 and the last one survived until it was scrapped in 1947.
Design and development
The 18-inch gun had its genesis in the insistence of the First Lord of the Admiralty, Admiral Fisher, for the biggest possible gun mounted on the fastest possible ship. He conceived of what he called "large light cruisers" carrying four 15-inch (380mm) guns, which became the Courageous class, but he wanted their half-sisterFurious to carry an even bigger gun.[2] The Elswick Ordnance Company was the only company capable of manufacturing such a large gun and began design work in 1915. It was designated as the "15-inch B" to conceal its real size and was derived from the design of the 15-inch Mk I already in service.[3]
The gun and its breech mechanism weighed a total of 149 long tons (151t), almost half again as much as the 15-inch gun's 100 long tons (102t). It was mounted in a single-gun turret, also designated as the 15-inch B, derived from the twin-gun 15-inch Mark I/N turret. The barbettes of Furious were designed to accommodate either turret, in case problems arose with the 18-inch gun's development. The gun could depress to −3° and elevate to a maximum of 30°. Ammunition development for the gun was naturally focused on anti-ship shells for Furious, and it fired a 3,320-pound (1,510kg), 4 crharmour-piercing, capped (APC) shell, at a muzzle velocity of 2,270ft/s (690m/s) to a distance of 28,900 yards (26,400m). It could fire one round per minute. The turret's revolving mass was 826 long tons (839t), only a slight 2% more than the 810 long tons (823t) of its predecessor.[4]
The guns proved to be too powerful for Furious' light hull, and they became available for other uses during 1917, after trials showed the ship could not handle the stress of firing. Admiral Sir Reginald Bacon, commander of the Dover Patrol, conceived a plan to mount two guns inside the shell of the Palace Hotel in Westende from where they could bombard the naval facilities at Zeebrugge and Bruges, provided that the hotel was captured during the upcoming Battle of Passchendaele. He planned to transport the guns across the English Channel lashed to the torpedo bulges of monitors. He also thought that they could be used on the decks of monitors and as such a dual purpose carriage was designed for the guns, which could be used both afloat and ashore. Only a limited amount of traverse was required for either role, but elevation had to be increased to 45° to maximize range. The concept was approved 23 September 1917, and Elswick was ordered to design the new 'B CD' mounts for delivery in five months.[5]
The original concept for land use involved a special elevating slide that could traverse 6° to either side. Ammunition handling, elevation and ramming were to be done via hydraulic pump, but the breech was hand-worked. The gun was to be installed in a turf-covered concrete dome with a gunport for the barrel. As much as possible of the gun and its mount was designed to be assembled out of range of German artillery and then moved on a special broad-gauge railway to the site on specially-designed wheels. The transportable section weighed 210 long tons (213t).[6]
A view of the stern of Lord Clive, showing her 18-inch gun in its fixed mounting (November 1918)
After the British Army failed to capture Westende, the mounting was optimised for use on a monitor. It was very simple, consisting of two large girders connected together at each end with the gun and its carriage between them. The mount could only traverse 10° inside its fixed, ½-inch (12.7mm) gun shield and was aimed over the starboard side of the monitor. It was loaded at a fixed angle of 10°, but it could only fire between 22° and 45° to equalize the stresses on the carriage and the ship. It was provided with hydraulically powered cranes, loading tray, rammer and breech mechanism to minimize the crew's workload, but the ammunition parties had to use muscle power. The shells were stowed below deck and had to be moved by overhead rail to the hatch in the deck behind the gun to be lifted up and loaded. The cordite propellant charges were kept in eighteen steam-heated storage tanks mounted on the forecastle deck abaft the funnel and moved to the gun on a bogie mounted on rails, two one-sixth charges at a time, which reduced the rate of fire to about one round about every 3–4 minutes. The monitors had to be extensively modified to handle the gun. Numerous additional structural supports had to be added underneath the gun to support its weight of 384 long tons (390t); the sides had to be plated in to accommodate the additional crewmen and the interior rearranged for the 18–inch shells and the loading arrangements.[7]
Service
Furious, fitted with a single, aft 18 inch gun and a forward flight deck (1917)
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.[3] The new 'B CD' mounts were delayed, and the mount for Lord Clive-classmonitorGeneral 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.[8]
On board Lord Clive; her BL 18 inch gun is at its full elevation, November 1918
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 (74.8kg), making a total of 690 pounds (313.0kg) propellant, and increasing the elevation to 45° extended the range to about 36,900 yards (33,700m) with the existing 4 crh shells. New 8 crh 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.[9]
General Wolfe was assigned to the Dover Patrol on 15 August 1918, 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 (6.4km) south of Ostend) at a range of 36,000 yards (32,918m) and made naval history as the heaviest shell fired from the largest gun at the longest range in action.[10] 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.[11]
A gun and its shells being prepared for display at the Imperial War Museum and Great Victory Exhibition at the Crystal Palace, London, 1920
The second gun, Furious' spare, was mounted in Lord Clive, but she was not ready for combat until 13 October 1918. 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.[12] A total of 85 18-inch shells were fired in action by both guns.[4] Wear on General Wolfe's gun was measured at about 0.37in (9.4mm) after firing 161 effective full charges (EFC) - 105 rounds including proof and practice, with 57 being supercharges. This indicates the gun would have been good for well over 300 EFC, comparable with most other British ordnance using Cordite MD.[13]
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 (410mm) 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.[14]
Burt, R. A. (1986). British Battleships of World War One. Annapolis, MD: Naval Institute Press. ISBN0-87021-863-8.
Buxton, Ian (2008). Big Gun Monitors: Design, Construction and Operations 1914–1945 (2nd, revised and expandeded.). Annapolis, MD: Naval Institute Press. ISBN978-1-59114-045-0.
Campbell, N. J. M. (1979). "British Super-Heavy Guns, Part 3". Warship III. London: Conway Maritime Press. pp.196–201. ISBN0-85177-204-8.
Hodges, Peter (1981). The Big Gun: Battleship Main Armament 1860-1945. Annapolis, MD: Naval Institute Press. ISBN0-87021-917-0.
Roberts, John (1997). Battlecruisers. Annapolis, MD: Naval Institute Press. ISBN1-55750-068-1.
HMS Erebus was a First World War monitor launched on 19 June 1916 and which served in both world wars. She and her sister ship Terror are known as the Erebus class. They were named after the two bomb vessels sent to investigate the Northwest Passage as part of Franklin's lost expedition (1845–1848), in which all 129 members eventually perished.
The Courageous class consisted of three battlecruisers known as "large light cruisers" built for the Royal Navy during the First World War. The class was nominally designed to support the Baltic Project, a plan by Admiral of the Fleet Lord Fisher that was intended to land troops on the German Baltic Coast. Ships of this class were fast but very lightly armoured, with only a few heavy guns. They were given a shallow draught, in part to allow them to operate in the shallow waters of the Baltic but also reflecting experience gained earlier in the war. To maximize their speed, the Courageous-class battlecruisers were the first capital ships of the Royal Navy to use geared steam turbines and small-tube boilers.
This article explains terms used for the British Armed Forces' ordnance (weapons) and ammunition. The terms may have different meanings depending on its usage in another country's military.
The BL 15-inch Mark I succeeded the BL 13.5-inch Mk V naval gun. It was the first British 15-inch (380 mm) gun design and the most widely used and longest lasting of any British designs, and arguably the most successful heavy gun ever developed by the Royal Navy. It was deployed on capital ships from 1915 until 1959 and was a key Royal Navy gun in both World Wars.
The Lord Clive-class monitor, sometimes referred to as the General Wolfe class, were ships designed for shore bombardment and were constructed for the Royal Navy during the First World War.
The BL 14-inch Mk VII naval gun was a breech loading (BL) gun designed for the battleships of the Royal Navy in the late 1930s. This gun armed the King George V-class battleships during the Second World War.
The BL 6-inch gun Mark VII was a British naval gun dating from 1899, which was mounted on a heavy travelling carriage in 1915 for British Army service to become one of the main heavy field guns in the First World War, and also served as one of the main coast defence guns throughout the British Empire until the 1950s.
HMS General Craufurd was the one of eight Lord Clive-class monitors built for the Royal Navy during World War I. Their primary armament was taken from obsolete pre-dreadnought battleships. The ship spent the war in the English Channel bombarding German positions along the Belgian coast as part of the Dover Patrol. She participated in the failed First and Second Ostend Raids in 1918, bombarding the defending coastal artillery as the British attempted to block the Bruges–Ostend Canal. Later that year General Craufurd supported the coastal battles during the Hundred Days Offensive until the Germans evacuated coastal Belgium in mid-October. The ship was decommissioned almost immediately after the war ended the following month, but she was reactivated in 1920 to serve as a gunnery training ship for a year. General Craufurd was sold for scrap in 1921.
HMS Lord Clive was the lead ship of her class of eight monitors built for the Royal Navy during World War I. Their primary armament was taken from obsolete pre-dreadnought battleships. The ship spent the war in the English Channel bombarding German positions along the Belgian coast as part of the Dover Patrol, often serving as a flagship. She participated in the failed First Ostend Raid in 1918, bombarding the defending coastal artillery as the British attempted to block the Bruges–Ostend Canal. Lord Clive was one of two ships in the class fitted with a single 18-inch (457 mm) gun in 1918, but she only fired four rounds from it in combat before the end of the war in November. The ship conducted gunnery trials after the war and was sold for scrap in 1927.
HMS General Wolfe, also known as Wolfe, was a Lord Clive-class monitor which was built in 1915 for shore-bombardment duties in the First World War. Her class of eight ships was armed by four obsolete Majestic-class pre-dreadnoughts which had their 12-inch guns and mounts removed, modified and installed in the newly built monitors. Wolfe spent her entire war service with the Dover Patrol, bombarding the German-occupied Belgian coastline, which had been heavily fortified. In the spring of 1918 she was fitted with an 18-inch (457 mm) gun, with which she made the longest-range firing in the history of the Royal Navy - 36,000-yard (20 mi) - on a target at Snaeskerke, Belgium. After the war, she was laid up before being stripped and put up for sale in 1920. She was finally scrapped in 1923.
The Armstrong Whitworth 12-inch naval gun of 40 calibres length was designed by and manufactured mainly by Armstrong's ordnance branch, Elswick Ordnance Company. It was intended for the Royal Navy's Royal Sovereign-class battleships, but budgetary constraints delayed their introduction. The first units were instead supplied to Japan. As the Type 41 12-inch (305 mm) 40-calibre naval gun it was the standard main battery on several early United Kingdom-built pre-dreadnought battleships of the Imperial Japanese Navy.
The Gorgon-class monitors were a class of monitors in service with the Royal Navy during World War I. Gorgon and her sister ship Glatton were originally built as coastal defence ships for the Royal Norwegian Navy, as HNoMS Nidaros and HNoMS Bjørgvin respectively but requisitioned for British use. Gorgon commissioned first, in June 1918 and bombarded German positions and other targets in Occupied Flanders. She fired the last shots of the war by the Royal Navy into Belgium on 15 October 1918. She was offered for sale after the war, but was used as a target ship when there were no takers. She was sold for scrap in 1928. Glatton was destroyed by a magazine explosion only days after she was completed in September 1918 while in Dover Harbour. She remained a hazard to shipping until the wreck was partially salvaged and the remains moved out of the way during 1925–26.
The BL 13.5 inch naval gun Mk I was Britain's first successful large breechloading naval gun, initially designed in the early 1880s and eventually deployed in the late 1880s. Mks I - IV were all of 30 calibres length and of similar construction and performance.
The BL 12-inch Mark VIII naval gun was one of the first large British rifled breech-loading naval guns designed for the higher pressures generated by the new cordite propellant of the 1890s, and Britain's first large wire-wound gun. It represented a major advance compared to previous British guns.
The BL 9.2-inch Mk IX and Mk X guns were British breech loading 9.2-inch (234 mm) guns of 46.7 calibre, in service from 1899 to the 1950s as naval and coast defence guns. They had possibly the longest, most varied and successful service history of any British heavy ordnance.
The BL 6-inch gun Marks II, III, IV and VI were the second and subsequent generations of British 6-inch rifled breechloading naval guns, designed by the Royal Gun Factory in the 1880s following the first 6-inch breechloader, the relatively unsuccessful BL 6-inch 80-pounder gun designed by Elswick Ordnance. They were originally designed to use the old gunpowder propellants but from the mid-1890s onwards were adapted to use the new cordite propellant. They were superseded on new warships by the QF 6-inch gun from 1891.
The 14-inch/45 caliber gun,, whose variations were known initially as the Mark 1, 2, 3, and 5, and, when upgraded in the 1930s, were redesignated as the Mark 8, 9, 10, and 12. They were the first 14-inch (356 mm) guns to be employed by the United States Navy. The 14-inch/45 caliber guns were installed as the primary armament aboard all of the United States Navy's New York-class, Nevada-class, and Pennsylvania-class battleships. The gun also saw service in the British Royal Navy, where it was designated BL 14 inch gun Mk II.
The BL 6-inch Mark XII naval gun was a British 45 calibre naval gun which was mounted as primary armament on light cruisers and secondary armament on dreadnought battleships commissioned in the period 1914–1926, and remained in service on many warships until the end of World War II.
The BL 12-inch Mark XI and Mark XII gun were British breech loading (BL) naval guns of 50-calibres length mounted as primary armament on dreadnought battleships from 1910.
The BL 8 inch gun Mark VIII was the main battery gun used on the Royal Navy's County-class cruisers, in compliance with the Washington Naval Treaty of 1922. This treaty allowed ships of not more than 10,000 tons standard displacement and with guns no larger than 8 inches (203 mm) to be excluded from total tonnage limitations on a nation's capital ships. The 10,000 ton limit was a major factor in design decisions such as turrets and gun mountings. A similar gun formed the main battery of Spanish Canarias-class cruisers. In 1930, the Royal Navy adopted the BL 6 inch Mk XXIII naval gun as the standard cruiser main battery in preference to this 8-inch gun.
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