BL 18 inch Mk I naval gun
| 18 inch Mark I | |
|---|---|
| 300px On the monitor HMS General Wolfe (1915) | |
| Type | naval gun |
| Place of origin | United Kingdom |
| Service history | |
| In service | 1918 |
| Used by | Royal Navy |
| Wars | World War I |
| Production history | |
| Designer | Elswick Ordnance Company |
| Designed | 1915–16 |
| Manufacturer | Elswick Ordnance Company |
| Produced | 1916–17 |
| Number built | 3 |
| Specifications | |
| Weight | 149 long tons (151 t) |
| Length | 744.15 inches (1,890 cm) |
| Barrel length | 720.2 inches (1,829 cm) |
| | |
| Shell weight | 3,320 pounds (1,510 kg) |
| Caliber | 18 inches (460 mm) |
| Breech | Welin breech block |
| Recoil | hydro-pneumatic |
| Elevation | +22° to +45° |
| Traverse | 10° |
| Muzzle velocity | 2,420 feet per second (738 m/s) |
| Effective range | 31,400 yards (28,712 m) |
| Maximum range | 40,500 yards (37,033 m) |
| Filling weight | 243 pounds (110 kg) |
The British BL 18-inch (460 mm) Mk I naval gun was a naval gun in the service of the Royal Navy during the First World War. It was the largest and heaviest gun ever used by the British. Only the Second World War Japanese 40 cm/45 Type 94 had a larger calibre, 18.1 inches (46 cm), but the British shell was heavier. 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. Three guns were built, but they did not see combat with Furious as they were removed from her before completion and transferred to the Lord Clive-class monitors General Wolfe and Lord Clive for coast bombardment duties. Only 85 rounds were fired in anger 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 (380 mm) guns which became the Courageous-class, but he wanted their half-sister Furious to carry an even bigger gun.[1] 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.[2]
As mentioned above, these were wire wound guns whose construction generally resembled that of the 15"/42 (38.1 cm) Mark I but with a relatively small breech ring. Construction consisted of inner A tube, A tube, wire-winding, B tube, jacket, shrunk on collar and breech ring. Over 200 miles (325 km) of 0.25 × 0.06 in (0.635 × 1.52 cm) of high-tensile steel wire was used. The Welin breech block use on these guns was significantly different in that the Vickers' "pure couple" mechanism of the 15" (38.1 cm) was replaced with the Elswick short arm mechanism for reasons of reducing "slam" as the breech closed. In this design, the breech screw withdrew through the carrier, which complicated the locking action. However, this mechanism was fast-acting, with about three seconds being needed to open or close the breech.[3]
The gun and its breech mechanism weighed a total of 149 long tons (151 t), almost half again as much as the 15-inch gun's 100 long tons (100 t). 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 and 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 the Furious and it fired a 3,320-pound (1,510 kg), 4crh armour-piercing, capped (APC) shell at a muzzle velocity of 2,270 ft/s (690 m/s) to a distance of 28,900 yards (26,400 m). It could fire one round per minute. The turret's revolving mass was 826 long tons (839 t), only slightly more than the 810 long tons (823 t) of its predecessor.[3]
The guns proved to be too much for Furious' light hull and they became available for other uses during 1917. 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 it was captured during the upcoming Battle of Passchendaele. He planned to transport the guns across the English Channel lashed to the bulges of monitors. He also thought that they could be used on the decks of monitors so that a dual purpose carriage was designed for the guns, that 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 ordered to design the new 'B CD' mounts for delivery in five months.[4]
The failure of the British Army to capture Westende meant that 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 (12.7 mm) 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 (390 t), 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.[5]
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 converted to a seaplane carrier. The second gun followed later in 1917 after trials showed the vessel could not handle the stress of firing and she was converted into an aircraft carrier.[6] 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 dominated the ship's profile.[7]
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 (75 kg), making a total of 690 pounds (313 kg) propellant, and increasing the elevation to 45° extended the range to about 36,900 yards (33,741 m) with the existing 4crh shells. New 8crh high explosive shells, with a longer, thinner ballistic cap, were ordered, but only two 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.[8]
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 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.[9] She fired 52 shells that day and found that the recoil from her 18–inch gun literally shoved 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.[10]
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.[11] A total of 85 18-inch shells were fired in action.[3]
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 she 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 use in cordite-proving tests for the BL 16 inch Mk I naval gun intended for the cancelled G3 battlecruisers, but actually 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, although they were scrapped in 1933. [12]
One mount survived and was used to mount a spare BL 14 inch Mk VII naval gun from the battleship HMS King George V (41) and emplaced near Dover in 1940. The combination was named 'Pooh', after Winnie-the-Pooh.[13]
- HMS Furious-1.jpg
HMS Furious in 1917 showing 18-inch turret
- Furious Turret pic.jpg
A close-up of the turret
See also
- List of naval guns
- 40 cm/45 Type 94 World War II Japanese 18-inch gun
Notes
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<references />, or <references group="..." />Bibliography
- Burt, R. A. (1986). British Battleships of World War One. Annapolis, MD: Naval Institute Press. ISBN 0-87021-863-8.
- Buxton, Ian (2008). Big Gun Monitors: Design, Construction and Operations 1914–1945 (2nd, revised and expanded ed.). Annapolis, MD: Naval Institute Press. ISBN 978-1-59114-045-0.
- Roberts, John (1997). Battlecruisers. Annapolis, MD: Naval Institute Press. ISBN 1-55750-068-1.
External links
Template:GreatWarBritishNavalWeapons- ↑ Burt, p. 308
- ↑ Buxton, p. 225
- ↑ 3.0 3.1 3.2 "British 18"/40 (45.7 cm) Mark I". 22 October 2009. Retrieved 16 November 2009.
- ↑ Buxton, pp. 225–26
- ↑ Buxton, pp. 73–74, 226–27
- ↑ Buxton, p. 225
- ↑ Buxton, p. 73
- ↑ Buxton, p. 227
- ↑ Buxton, pp. 66–67
- ↑ Buxton, p. 66-68
- ↑ Buxton, pp. 67–68, 227
- ↑ Buxton, pp. 68, 74, 227–28
- ↑ Buxton, p. 228
