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36-873: Five massive 15–inch naval guns were installed in Singapore by the British government before 1940, with three based in Changi to the east and two located in Buona Vista to the southwest. Collectively, the three naval guns in Changi formed the Johore Battery , named after the King of Johor, Sultan Ibrahim , who gave King George V of the UK a grand royal gift of £500,000 for his Silver Jubilee in 1935, of which £400,000 of

72-622: A dimensionless quantity. For example, the main guns of the Iowa -class battleships can be referred to as 16"/50 caliber. They are 16   inches in diameter and the barrel is 800   inches long (16 × 50 = 800). This is also sometimes indicated using the prefix L/; so for example, the most common gun for the Panzer V tank is described as a "75 mm L/70," meaning a barrel with an internal bore of 75 mm (3.0 in), and 5,250 mm (17 ft 3 in) long. The bore to barrel length ratio

108-421: A 12/45 is 12"×45= the length of the rifled bore of that gun in inches. This explains the differences in both penetration and long range performance of various naval rifles over the years. In addition to the possible improvements in overall performance (i.e. muzzle velocity and striking force), the increase in barrel length also allowed, in some circumstances, an increase in projectile size as well. For example,

144-403: A 15-inch gun was approximately 335 full charge firings using standard charges, after which it had to be re-lined. All shipboard mounts of the gun were in twin turrets. All mountings were designated Mk I, with an as-built maximum elevation of 20°, though some were subject to later modifications. HMS Hood, however, had its guns in a unique mounting, designated Mk II. Incorporating experience from

180-444: A 2,200 lb (1,000 kg) shell. The later re-design to 50 calibre not only allowed a higher velocity, but also a heavier 2,700 lb (1,200 kg) shell, which ultimately came to be accepted as the greatest naval shell ever deployed in combat . Early gun barrels were short and thick, typically no more than 26 calibers, as the gunpowder propellant they used burned very quickly and violently, and hence its acceleration time

216-477: A dummy 15-inch shell, placed upon a modern large lifting-lever; allowing visitors to have a feel of its 800kg weight by trying to hoist it up from the ground. The old, and still inaccessible, tunnels are marked out in a maze of above ground trails. A plaque detailing the history of the battery is present at the hut forming the entrance to the site. Admission to the site of the battery is free with opening hours 09:00 to 17:00 Monday to Friday. The compound also includes

252-473: A new gun's development were bypassed, and it was ordered straight from the drawing board. Despite its hurried development process, the gun met all expectations and was a competitive battleship main armament throughout both World Wars. According to an American report produced after World War II, the British 15 inch Mk I was the most reliable and accurate battleship main armament of the war, though other guns and mountings had superior individual features. The barrel

288-608: A restaurant. . BL 15 inch Mk I naval gun 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 BL 15-inch Mk I, designed by Vickers, Son, and Maxim in 1912,

324-461: A revolving weight of 855 tons. The Mk II mounts of HMS Hood had a revolving weight of 860 tons. The BL 15-inch Mark I gun proved its effectiveness at the Battle of Jutland in 1916, scoring hits out to 19,500 yards (17,800 m), a record for naval gunnery at that time. In World War II the gun was responsible for the longest range shell-hit ever scored by one battleship on another in combat. At

360-559: A strong and a powerful navy by the later part of the 1930s and was expanding deeper and deeper into China), the Johore Battery is a large gun emplacement site consisting of a labyrinth of tunnels. These tunnels were used to store quantities of ammunition for the three 15-inch guns (most of which were of the armour-piercing (AP) type rather than the high-explosive (HE) type as these naval guns were intended to be employed against heavily armoured enemy warships). These naval guns were

396-403: Is available for expanding gas from the controlled burning of the propellant charge to smoothly accelerate the projectile, bringing about a higher velocity without placing undue strain on the gun. In internal ballistics terms, if the base of a projectile is thought of as a piston propelled by the expanding gas, then as barrel length increases the volume swept by the piston also increases, and hence

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432-576: Is called "caliber" in naval gunnery, but is called "length" in army artillery. Before World War II, the US Navy used 5"/51 caliber (5" L/51) as surface-to-surface guns and 5"/25 caliber (5" L/25) as surface to air guns. By the end of World War II, the dual purpose 5-inch/38-caliber gun (5" L/38) was standard naval armament against surface and air targets. All three had a bore diameter of 5   inches (not 5.51 or 5.25 or 5.38 as often misread). Naval rifles, although constructed and manufactured in roughly

468-520: Is impossible to measure. In modern guns, increased muzzle velocities can be produced by altering powder composition and/or using duplex charges containing two different powders in order to extend the "pressure curve" further down the bore. By exposing the projectile base to a given pressure for a longer length of time, velocity can be increased without elevating the pressure level generated. Technological improvements had made it possible to introduce into use long gun barrels that are strong enough to withstand

504-717: The Battle of Calabria on 9 July 1940, HMS  Warspite gained a hit on the Italian battleship Giulio Cesare with her first salvo at 26,400 yards (24,100 m). In the Attack on Mers-el-Kébir , when the French fleet was largely neutralised following the fall of France to the Germans, the BL 15-inch Mark I gun (arming HMS  Hood , HMS  Valiant and HMS  Resolution )

540-759: The Battle of Jutland , the Mk II mounting had a maximum elevation of 30°, thus increasing the maximum range. In the 1930s a modification of the Mk I mounting, designated the Mk I (N), was introduced for use in those capital ships that were completely reconstructed. The Mk I (N) mounting also increased the maximum elevation from 20° to 30°. Maximum range in shipboard mountings was 33,550 yards (30,680 m) (30° elevation). During World War II unreconstructed older battleships, with gun elevation limited to 20°, were supplied with supercharges to increase their maximum range to 29,930 yards (27,370 m) at 2,638 ft/s (804 m/s) using

576-602: The Imperial War Museum in London. Caliber (artillery) In artillery , caliber or calibre is the internal diameter of a gun barrel, or, by extension, a relative measure of the barrel length. Rifled barrels introduce ambiguity to measurement of caliber. A rifled bore consists of alternating grooves and lands. The distance across the bore from groove to groove is greater than the distance from land to land. Projectiles fired from rifled barrels must be of

612-560: The American 14/45, as introduced in the New York -class battleships, fired a 1,250 lb (570 kg) projectile. Later improvements to the design, lengthening the rifle itself and also altering the breech, allowed a 1,400 lb (640 kg) projectile and, overall, a greater barrel life. Again we see this pattern with the US 16" guns. The initial design was 45 calibers in length and fired

648-495: The Mk XVIIB or Mk XXII projectile, while HMS Vanguard could theoretically range to 37,870 yards (34,630 m) while using supercharges at a gun elevation of 30°. Coastal artillery mountings with higher elevations could reach 44,150 yards (40,370 m). The Mk I mounting had a revolving weight of 750 tons (1915) and 785 tons (1935). The Mk I (N) had a revolving weight of 815 tons; the Mk I (N) RP12 mounts of HMS Vanguard had

684-417: The amount of energy that can be extracted from the gas's burning increases. A longer barrel allows more propellant to be used: the propellant is all burned fairly early in the projectile's journey along the barrel, except in the very common instance where combustion is still occurring as the projectile leaves the muzzle and a visible muzzle "flash" is produced. The projectile continues to accelerate as long as

720-570: The amount was used by the British government to fund the installation of the three large naval guns in Changi. In early 1942, the Johore Battery was employed in the Allied artillery bombardment of Johor Bahru , which at that time was under Japanese military occupation following the retreat of all Allied forces from British Malaya to Singapore. Built by the British government in 1939 for the naval defence of Singapore (in particular, to defend Singapore from an aggressive Imperial Japan , which had possessed

756-449: The barrel and a copper driving band somewhat larger than the groove-to-groove diameter to effectively seal the bore as it becomes enlarged by erosion during prolonged firing. United States Navy guns typically used rifling depth between one-half and one percent of caliber. Projectile bourrelet diameter specification was 0.015 inches (0.38 mm) less than land-to-land diameter with a minus manufacturing tolerance, so average clearance

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792-537: The forces involved in accelerating the shell to a high velocity, while remaining light enough to be reasonably mobile, rigid enough to maintain accuracy, and having a bore able to withstand many firings before needing refurbishment. In World War I 45-caliber naval gun barrels were typical, in World War II 50- to 55-caliber barrels were common, with Germany already manufacturing tank guns of 70 calibers by 1943. Today, 60- to 70-caliber barrels are not uncommon, but

828-427: The full groove-to-groove diameter to be effectively rotated by the rifling, but the caliber has sometimes been specified as the land-to-land diameter before rifling grooves were cut. The depth of rifling grooves (and the consequent ambiguity) increases in larger calibers. Steel artillery projectiles may have a forward bourrelet section machined to a diameter slightly smaller than the original land-to-land dimension of

864-462: The largest to be installed on land outside of Britain itself during World War II. They were all destroyed before the official surrender of the British Army on 15 February 1942 to the conquering Imperial Japanese military and the related tunnels (for the storage of the ammunition for the guns and gun-crew quarters) were sealed up and almost forgotten after the war in 1945. In 1948 one of the guns

900-525: The last battleship to be built for the Royal Navy , completed in 1946. Warships armed with the BL 15-inch Mark I gun: 186 guns were manufactured between 1912 and 1918. They were removed from ships, refurbished, and rotated back into other ships over their lifetime. Two guns, one formerly from HMS  Ramillies (left gun) and the other originally mounted in HMS ; Resolution , but later moved to HMS  Roberts (right gun), are mounted outside

936-415: The pressure behind it is sufficient to overcome bore friction. The excess energy will continue to accelerate the projectile until it exits the muzzle. If the pressure behind the projectile drops sufficiently before the projectile exits the bore, the projectile can and will slow while still within the barrel, despite residual bore pressure behind the projectile. A light charge with insufficient pressure to expel

972-405: The projectile will result in a "squib", or projectile lodged in the bore. This pressure is reduced by the increasing barrel volume the gas has to fill. In order to achieve maximum muzzle velocity with the shortest barrel length, the projectile should exit the barrel as the gas pressure reduces to a small fraction of the maximum, although unlike maximum chamber pressure, the small fraction desired

1008-400: The same manners as land-based artillery, were built to much more stringent and studious standards than land-based weapons, and for good reason. At sea, a weapon had to perform, without fail. There was no ready replacement, nor one that could be readily supplied. Over time, the terms of pound (weight of shell ) and bore (the actual bore of the weapon) became confused and blurred. Eventually, when

1044-426: The technology existed, the bore (in inches or millimetres) came to be the standard measure. For naval rifles, the initial change was to actual bore, thus facilitating the manufacture of standard projectiles. They then began to measure the effective length (and therefore range) of the weapon in calibers. These are a measure of the standardized length of the barrel versus the rifled bore of the barrel. In other words,

1080-655: Was 42 calibres long (i.e., length of bore was 15 in x 42 = 630 in) and was referred to as "15 inch/42". Overall length of gun: 650.4 inches, Weight of gun, excluding breech mechanism: 97 tons 3cwt. Weight of breech mechanism: 2 tons 17cwt. Rifling: polygroove, 76 grooves, uniform right-hand twist of one turn in 30 calibres. This wire-wound gun fired at a muzzle velocity of 2,450 ft/s (750 m/s) (4 crh shell), 2,640 ft/s (6 crh shell) with supercharge. Weight of shell: 1,920 lbs (4 AP crh shell), 1,938 lbs (6 crh AP shell – 1937). Weight of charge: 428 lbs cordite, 490 lbs cordite for supercharge. The firing life of

1116-403: Was about 0.012 inches (0.30 mm). Driving band diameter was groove-to-groove diameter plus 0.02 inches (0.51 mm). The length of the barrel (especially for larger guns) is often quoted in multiples of the caliber, used, for example, in US naval rifles 3 in (76 mm) or larger. The effective length of the barrel (from breech to muzzle ) is divided by the barrel diameter to give

Johore Battery - Misplaced Pages Continue

1152-409: Was an enlarged version of the successful BL 13.5-inch Mk V naval gun . It was specifically intended to arm the new Queen Elizabeth -class battleships as part of the British response to the new generation of Dreadnought battleships Germany was building, during the naval arms race leading up to World War I. Due to the urgency of the times, the normally slow and cautious prototype and testing stages of

1188-660: Was demolished and returned to England as scrap. In 1950 the Royal Army Ordnance Corps began an exercise to remove live gun shells that were buried at Changi during the British evacuation in 1942. The location remained unknown until the Singapore Prisons Service discovered them by chance in April 1991. The former site of the Johore battery now includes a replica of the large naval gun and

1224-434: Was needed by weight as they transformed almost entirely to gases when burned. Muzzle velocity became limited only by the length of barrel that was feasible, both in terms of the construction methods of the day and in terms of any practical constraints imposed by the gun's manner of use. The practical effect of long barrels for modern guns is that the projectile spends more time in the barrel before it exits, and hence more time

1260-472: Was responsible for the destruction by a magazine explosion of the old battleship Bretagne , and the disabling and beaching (deliberate running aground in shallow water) of the old battleship Provence and the new battleship Dunkerque . Dunkerque' s main 225mm armour belt was twice penetrated by 15-inch shells, which destroyed its fighting and steaming abilities. These guns were used on several classes of battleships from 1914 until HMS  Vanguard ,

1296-513: Was short. Slower-burning " brown powder " formulations of gunpowder allowed gun barrel length to increase slightly in the 1880s, but enormous quantities of brown powder were required. New slower-burning " smokeless powder " propellants available from the mid-1880s onwards, such as Poudre B , cordite and nitrocellulose allowed a gentler prolonged acceleration, hence gun barrels were made progressively longer and thinner. The new formulations were far more powerful propellants than gunpowder and far less

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