GUNBOAT 



3747 



GUNCOTTON 



ammunition hoists are centrally 

 situated, and trolleys from the 

 magazines or running gear load the 

 projectiles and charges on the 

 platform below, whence by hydrau- 

 lic or electric mechanism they are 

 rapidly raised to a point behind 

 the breech of the gun and auto- 

 matically rammed home. With the 

 increase of length to 50 calibres, 

 and the installation of 13'5-in. and 

 15 -in. guns, the weights have been 

 increased enormously, as will be 

 seen below. In the U.S. and Japan- 

 ese navies 16-in. guns have been 

 mounted in the latest ships. 

 Manufacture of Big Guns 



In the manufacture of modern 

 big guns the operation begins with 

 the casting of the steel ingot and 

 the forging of it under pressure in 

 some cases of 5,000 tons. The ingot 

 is bored by means of a trepanning 

 machine, and forged upon a man- 

 drel into the form of a tube at a 

 red heat under a powerful press 

 which has a downward force of 

 3,500 tons or more, the tube being 

 turned continuously during the 

 operation. Having thus been 

 forged approximately to the re- 

 quired dimensions, the gun tube is 

 next turned by lathes, and bored 

 by long machines, working usually 

 from both ends at the same time, 

 hardening or tempering being car- 

 ried out in a bath of rape -seed oil. 

 In British practice the gun is next 

 wound with steel ribbon, about a 

 quarter of an inch wide and a 

 tenth of an inch thick. On ths 12- 

 in. gun there is usually a length of 

 about 120 miles, weighing nearly 

 14 tons, with 14 layers at the 

 muzzle and 75 at the breech. Then 

 comes the shrinking on of the outer 

 jacket, at a very high temperature, 

 which when cooled becomes an in- 

 tegral part of the gun. After these 

 operations the gun is internally 

 rifled by special plant, and ex- 

 ternally machined. German guns 

 made by the Krupp company are of 

 the " built-up " type, strengthened 

 by the shrinking on of outer tubes, 

 whereby any tendency of the gun 

 to droop at the muzzle is stated to 

 be obviated. 



Improvements in Design 



The gun, with its breech and in- 

 tricate fittings, its complex mount- 

 ing, and its optical sighting and 

 firing gear, represents one of the 

 finest achievements of human in- 

 genuity. A single lever, moved in 

 various directions by hand, works 

 all the machinery in the gun- 

 house, opening the breech, placing 

 the gun in the loading position, 

 raising the loading cages, operating 

 the rammer, and closing the breech. 



During the Great War improve- 

 ments in guns were directed chiefly 

 to increasing the range and accur- 



acy of fire, mainly by altering the 

 shape of the projectiles, increasing 

 the elevation of the gun, and add- 

 ing to the muzzle velocity. The 

 enormous increase in the power of 

 modern guns will be seen from the 

 table on this page, which shows 

 the principal guns, indicating their 

 calibre-lengths. The figures of 

 velocity and energy in the case of 

 the 16-in. gun are approximations. 



classes, the larger being 238 ft. 

 long, with a draught of 4 ft. and a 

 speed of 14 knots, carrying two 

 6-in., two 12-pr., and six machine 

 guns ; the others (with names 

 ending in "-fly") were 120 ft. 

 long, with a draught of 2 ft. and a 

 speed of 9 - 5 knots, armed with one 

 4-in., one 6-pr., and four machine 

 guns. 



(2) Coast service gunboats, which 



It will be observed that, though 

 the muzzle velocity progressively 

 decreases, the muzzle energy is 

 continually increasing. 



The 13'5-in. was first mounted 

 in the Orion class of battleships, 

 1911-12, and the Lion and Tiger 

 classes of battle-cruisers. The 15-in. 

 gun was first installed in the Queen 

 Elizabeth. With the exception of 

 a few 18-in. guns mounted in 

 monitors during the Great War, 

 the largest gun in the British ser- 

 vice is the 15-in., of which eight 

 were mounted in the battle-cruiser 

 Hood, with secondary guns, twelve 

 of 5'5-in. and four of 4-in., the 

 latter being mounted for high- 

 angle fire against aircraft. 



Smaller Naval Weapons 



Little needs to be said of the 

 lesser guns of the British navy. 

 They are all mechanisms analogous 

 in make to the larger ones. The 

 9'2-in. fires a projectile of 380 Ib. 

 The 6-in. discharges ten aimed 

 rounds of 100 Ib. per minute. 

 There are also the 5'5-in., the 4'7- 

 in., and the 4-in. semi-automatic 

 gun for flotilla leaders, also the 4-in. 

 high-angle fire gun (rising to 80 or 

 90 degrees) for anti-aircraft prac- 

 tice. During the Great War some 

 special types of guns were intro- 

 duced, including a 12-in. which 

 was mounted in one or more sub- 

 marines, 11 -in. and 7'5-in. howit- 

 zers, a 10-in. muzzle-loading bomb- 

 thrower for use against submarines, 

 and a Y-gun for rapid firing of 

 bombs, loading alternately at one 

 breech and the other. 



John Leylaml 



Gunboat. Term properly ap- 

 plied to small craft capable of 

 operating in shallow waters and 

 limited areas, and in which the 

 gun assumes an unusual impor- 

 tance. In the British navy there 

 are four classes of gunboats : (1) 

 River gunboats, originally designed 

 for service on the great rivers of 

 China, were revived in the Great 

 War for the Mesopotamian cam- 

 paign. These last were of two 



are intended for service in the 

 estuaries of the Chinese and 

 African rivers. They are much 

 larger than the river gunboats, dis- 

 placing from 800 to 1,200 tons. 

 None have been built for many 

 years. (3) Coast defence gunboats, 

 which were built between 1 870 and 

 1880, armed with a single heavy 

 gun in the bows. They displaced 

 not above 370 tons, and were of 

 little practical use. (4) The smaller 

 monitors built for service hi the 

 Great War were officially classed 

 as gunboats. The earliest gunboat 

 to be built was the Staunch, de- 

 signed by G. W. Rendel and built 

 at Elswick, 1 867. She was nothing 

 more than a floating gun carriage, 

 carrying a 9-in. gun, which could 

 be lowered in to a well by hydraulic 

 power. She displaced 180 tons 

 and had a speed of 6 knots, and 

 an overall length of 75 ft. See 

 Battleship ; Destroyer ; Navy. 



Gunbus. Slang term for any 

 aeroplane which mounts one or 

 more guns. It is more especially 

 applied to a gun -carrying aeroplane 

 of a large typs. 



Guncotton. Nitrocellulose of 

 the highest possible degree of nitra- 

 tion, containing about 13 p.c. of 

 nitrogen in commercial practice. 

 Cotton waste is the raw material 

 generally employed in the manu- 

 facture of guncotton. It is given a 

 drastic treatment with alkali to 

 remove all grease, boiled with 

 several changes of water, dried, 

 picked over by hand to remove 

 impurities, opened out by a teasing 

 machine, and then desiccated. Ths 

 nitrating acid contains about 75 

 p.c. sulphuric acid, 17 p.c. nitric 

 acid, and 8 p.c. water, the propor- 

 tions varying somewhat according 

 to the process employed, these 

 being detailed in the article on 

 nitrocellulose. When nitration is 

 complete the guncotton is im- 

 mersed hi water and thoroughly 

 washed to remove the bulk of the 

 acids, and then undergoes a treat- 

 ment, termed stabilisation, to 



