Table IV.Particulars of the Successive Large Naval Guns, 1800 to 1905.Year.Type.Weight.Length.Calibre.Weight of Projectile.Weight of Charge.Muzzle Energy.Penetration ofWrought Iron at 1000 Yards Range.tonscwt.in.in.lb.lb.ft.-tns.in.1800Cast-ironsmooth-bore2121146.432104001842Ditto415...8.1268167001865Woolwichwrought-iron410...711522140071870Built-upmuzzle-loader38020012.5081020013,900171880Ditto80032116170045027,96022-1/21887Built-upbreech-loader1101052416.25180096054,390321895Wire-woundbreech-loader460445.512850...33,94034.61900Ditto510496.51285021036,29035.41905Ditto58054012850...49,56042
Table IV.
Particulars of the Successive Large Naval Guns, 1800 to 1905.
Attention was further directed to the improvement of explosives; and ultimately, instead of gunpowder having a potential energy of 480 foot-tons per pound, modified gun-cotton was introduced, with an energy of 716 foot-tons per pound, and still later there were evolved explosive compounds of which the potential energy per unit of weight was fourfold greater than in the case of gunpowder, namely, 1139 foot-tons per pound. Finally, the explosive has taken the form of cordite, which ensures slow burning, great expansion, and, consequently, augmented propelling power behind the projectile, without material addition to the maximum strain upon the weapon. But in any case the constructional strength of the modern gun is enormously superior to the earlier built-up weapons, as around theinner tubes there is coiled something like 120 miles of wire, which itself has a breaking-strain of between 90 and 110 tons per square inch, and is put on under a tension of from 54 tons per square inch on the inner wires to 32 tons per square inch on the outer wires,[63]so that the ultimate resistance to strain consequent upon the firing of the gun is enormously increased. Velocities of 2600 ft. per second are thus realised, and even more is quite feasible, so that penetration of wrought iron at 1000 yards range has now been increased to 42 in.
If we compare the 12-in. gun to-day with the weapon of the same calibre of twenty years ago, when there was no widened chamber for the explosive, when prismatic powder of low expansive power was used, it is found, as shown in the Table opposite, that the penetration at 1000 yards has been doubled, and the possible effective range multiplied fivefold. There has also been an enormous gain in quicker fire by improved breech mechanism and efficient hydraulic and electric mountings, whereby the gun and all its loading, elevating, and training machinery is rotated.
The metallurgist has also been successfully occupied, and it is probable that the armour plate of to-day is still invulnerable. The earlier wrought-iron plates were increased from 4-1/2 in. in thickness on theWarriorof 1861, to the 24 in. on theInflexibleof 1881; the area protected being almost proportionately reduced. The artillerist with improved projectiles ultimately defeated this heavy cleading on the ships; but compound armour, first made in 1879, enabled the maximum thickness on the broadside to be reduced to 18 in., permitting a greater area to be covered for the same weight. At first the 80-ton gun failed in its attack, but heavier weapons, with improved projectiles, prevailed. The next step was the introduction of all-steel armour in 1890. Two years later there was introducedthe super-carburising and subsequent chilling of the face of plates made of an alloy of nickel steel. In 1897 the process of hardening was still further developed, and now the 9-in. plate on the modern battleship is equal in resistance to a 26-in. wrought-iron plate of the 'sixties, or a 20-in. compound-plate of the 'eighties, or a 13-in. plate of the early-hardened type. For the present, therefore, the armour seems to have secured the victory, as at 5000 yards range 9-in. armour can scarcely be defeated by even the 12-in. gun.
With the increased resistance of armour and the consequent reduction in its thickness, the naval designer can spread his protecting plates over a much wider area, so that the whole broadside of ships like thePrince of Wales, or the cruisersArgyllandDefence, is clad with armour of satisfactory resisting power. At the same time the gun-power and speed of ships have been greatly increased without making the displacement inordinately high. On the opposite page a Table gives the main features of representative ships at different epochs, which will show this at a glance.
The growth in the size of battleships has been steady, with the exception of the class represented by theBarfleurandCanopus, both of which were engined by the Scotts. These vessels are embodiments of a desire to check the advance in the size and cost of the battleship. The deficiency in the number and calibre of their guns was partly compensated by the introduction, for the first time in battleships, of quick-firing weapons of large calibre. TheBarfleurhad four 12 in. breechloaders and ten 4.7 in. quick-firers; while theCanopushad four 10 in. breechloaders and ten 6 in. quick-firers. But opinion has again strongly grown in favour of having in each British ship the best that can be achieved; and thus thePrince of Waleshas a displacement greater than any previous ship, while in theKing Edwardand theLord Nelsonclasses there has been a further growth in every element of power. The probabilities, too,are that we have not yet by any means seen the end of this advance.
Plate XIX.From a Photograph by West and Son, Southsea.HIS MAJESTY'S BATTLESHIP "PRINCE OF WALES," 1902.Larger image
Plate XIX.
From a Photograph by West and Son, Southsea.
HIS MAJESTY'S BATTLESHIP "PRINCE OF WALES," 1902.
Larger image