Warships and their story

by R. A. Fletcher

6-INCH B.L. 50-CALIBRE GUN COMPLETED AND WITH MOUNTING.

Photographs supplied by the Coventry Ordnance Works, Ltd.

No satisfactory results either with rifling or with the hexagonal bore could be obtained, and as guns became more powerful it was found that the only way of utilising them with the best results was by loading them at the breech instead of at the muzzle. Obviously, a heavy explosive shell could not be rammed down a big muzzle-loader. The old 32-pounder had a muzzle velocity of 1,600 feet per second, and the 40-pounder rifled breech-loader which took its place was of only 1,200 foot seconds, and the muzzle energy was 570 and 400 foot tons respectively. Various methods were employed and were not by any means satisfactory, but when slower burning powders were introduced, the strain upon the gun was less sudden and more cumulative, so that the pressure upon the projectile was exerted to the full as long as it was within the gun and it was then expelled at the muzzle with the greatest force obtainable. A great advance in naval gunnery was made with the appearance of the Armstrong breech-loader. The first breech-loader from this famous firm was a tube gun which was formed to admit of a breech block being dropped in to close the bore and a screw attachment held it fast. From about 1860 the principal guns in use in the Navy of the Armstrong screw type were the 9-pounder weighing 6 cwt., the 12-pounder weighing 8 cwt., the 20-pounder of 16 cwt., the 40-pounder of 35 cwt., and the 7-inch gun, 99½ cwt. The last-named was of 7.2 inches diameter, and fired projectiles weighing 109 lb. All these guns were on the polygroove system. About this time iron or steel gun carriages were introduced for use on shipboard. The Admiralty, for some reason best known to themselves, fancied muzzle-loaders, and obstinately remained faithful to them long after all other naval powers had discarded them as cumbersome and comparatively useless compared with the newer types of breech-loading guns. The newer muzzle-loaders, however, were improvements on the old smooth-bores, and were built on what is known as the Fraser system, and they were far larger than any which had been constructed before.

The inner barrels of the Armstrong 12-inch, 9-inch, and 7-inch muzzle-loading guns were of tempered steel, with solid ends; these were strengthened with wrought-iron coils shrunk on; the trunnion ring, breech-piece and cascable, which was screwed into the latter, were solid wrought-iron forgings. The different parts were hooked together with shoulders and corresponding recesses, to prevent their separation.

The muzzle-loader of 64 lb. on Fraser’s cheap construction plan consisted simply of a coiled iron tube, having the muzzle part double, but with a triple coil over the breech.

The Armstrong big muzzle-loading guns were formed with the Woolwich system of rifling or grooving, the projectiles being fitted with studs to correspond to the grooves. The muzzle-loading guns varied from the 7-inch 7-ton gun to the 16-inch 80-ton gun. The 8-inch was 118 inches in length, the 9-inch 125 inches, and so on, up to the 16-inch gun, which was 288 inches in length; the last-named took a charge of 450 lb., and fired a projectile weighing 1,684 lb. with a muzzle velocity of 1,590 foot seconds and a muzzle energy of 29,530 foot tons, capable of penetrating at the muzzle between 24 and 25 inches of wrought iron.

By 1877 the initial velocity of rifled projectiles had been increased from 1,600 to 2,100 foot seconds, and the energies by nearly 75 per cent., so that a further reconstruction of artillery became compulsory. It was not until after 1881 that the Admiralty definitely adopted heavy breech-loading guns for its armed cruisers. Even as late as 1885 the squadron sent to sea when it was feared that trouble with Russia was brewing, included thirteen battleships, not one of which had a breech-loading gun of more than 6 inches diameter. As a contrast to this, all the heavy guns of the Russian ships were breech-loaders. What would have happened to the English ships had hostilities occurred, and had the Russian gunners been able to use their weapons properly, is best left to conjecture, but it might have proved a sorry day in the naval history of England. Even by 1894 muzzle-loaders were still in use in the Navy.

The Woolwich Armstrong breech-loading guns varied from 12-pounders of 3 inches to the 16.25-inch 111-ton gun, the length of which was equal to 30 calibres. The last-named gun took a charge of 960 lb. of powder, and fired a projectile weighing 1,800 lb. with a muzzle velocity of 2,087 foot seconds, and a muzzle energy of 54,390 foot tons, calculated to penetrate over 36 inches of wrought iron at the muzzle. Gunpowder not being powerful enough for these great weapons, other explosives were introduced, which had, among other advantages, that of being much more powerful. The principal of these explosives at present in use is cordite.

In the early ’sixties the guns chiefly in use on this side of the Atlantic were the 9-inch gun, weighing 12 tons, and discharging a 250-lb. shot with 43 lb. of powder, the initial velocity being 1,730 feet per second. The largest gun was the 23½ tons, with a 12-inch diameter, its shot weighing 600 lb. and the charge of powder 70 lb., and the muzzle velocity being 1,240 feet per second. The larger guns could not be worked without considerable improvements being made in the ships themselves. Greater height had to be given between the decks, and the distances between the guns had also to be increased, there being 25 feet between the centre lines of the ports for the 12-ton guns, while the 23-ton guns required about 30 feet between the ports and between 8 and 9 feet between the deck and the underside of the beams supporting the deck above. To keep the portholes as small as possible an arrangement was made whereby the gun should be pivoted near the muzzle.