Armor - later turret ships
IN describing the ‘Inﬂexible’ I have stated that her turrets were protected with compound armour instead of the wrought-iron plates which up to that time had been employed. As the struggle between steel and compound plates had for some years been almost as keen as that between guns and armour, a brief history of this portion of our subject seems here desirable. I have read that about thirty years ago the present Sir john Brown happened to be at Toulon and saw the new French ironclad ‘La Gloire.’ Her plates were 5 ft. long, 2 ft. wide, and 41; in. thick. They had been hammered to these dimensions, as were all the plates of the early American monitors. Mr Brown—as he then was—came to the conclusion that such plates could be rolled, and on his return to England instituted a series of experiments which fully bore out this view.
When it was decided to put 4% in. of iron on the ‘Warrior,’ rolled plates of this thickness were manufactured without difﬁculty. In 1861 a target representing a section of the ‘ Warrior,’ and consisting of a 4§-in. iron plate, with 18 in. of teak backing, and an inner iron skin j} in. thick, was ﬁred at with a Whitworth riﬂed gun throwing a ﬂat-headed steel bolt of 80 lbs. The target was indented and cracked, but not perforated. In 1862 Mr Brown was able to roll at his works at Sheﬂield, in the presence of Lord Palmerston, an iron plate 18 ft. long, 4 ft. wide, and 5% in. thick. The f01~ lowing year, when the Lords of the Admiralty visited his works, at the opening of a new rof‘ing mill, the energetic manufacturer showed that plates up to a thickness of 12 in. could be produced.
From that time there was no difﬁculty in supplying the increased protection demanded for the new ironclad navy, till in the ‘Dreadnought’ we placed on the hull and turrets plates 14 in. thick. Though the water line amidships of the ‘Inﬂexible’ has 24. in. of iron, it is not in one but two plates, each 12 in. thick, with a layer of wood between them.
But already there were indications that no increase in the thickness of wrought-iron plates would sufﬁce to resist the growing energy of the gun. As early as 1869 a Krupp gun of 11 in. calibre had perforated 12 in. of iron and 36 in. of wood. Our own 38-ton gun pierced 19 in. of iron in 1876, and the following year the 80-ton gun sent its projectile through three 8-in. iron plates. In the meantime Mr Schneider had been developing at Creusot, in France, the manufacture of steel plates, and some experiments at Spezzia, in Italy, showed the softness of wrought-iron as compared with steel. The latter resisted penetration to a much greater extent, though it had a tendency to break up when attacked by numerous comparatively light projectiles. From this moment plates composed entirely of wrought-iron were doomed. The manufacturers of them in this country—Messrs Brown and Messrs Cammell—then proposed compound armour. In Cammell’s method—which is according to Wilson’s patent—a wrought~iron plate is put into a box, placed in a vertical position, and liquid steel poured in between one side of the plate and the side of the box.
The composite plate thus made is then rolled, by which process the steel face is hardened and made to adhere rigidly to the wrought-iron foundation. In Brown’s method—which is according to Ellis’s patent—instead of a box, a thin steel plate is placed at the required distance from the iron plate and the melted steel poured in between the two, making the whole a solid mass. It is then reheated and passed through the rolling mill. In both systems the steel face is about onethird the total thickness. In 1877 experiments with compound armour plates showed their superiority to wrought-iron, and consequently it was decided to place them on the ‘Inﬂexible’s’ turrets. In 1880 a compound plate made by Messrs Cammell, in which the steel face was 5 in. and the wrought-iron back 13 in. thick, was ﬁred at by the 38-ton gun, with a Palliser chilled shot, the result being that the projectile broke up on impact with the plate, and effected no damage beyond slight indentation and surface cracking. It was then evident that steel projectiles would henceforth be necessary to attack hard armour.
From that time up to the year 1889 the competition was between compound and ordinary steel plates. The latter resist perforation better, while the harder surface of the former is more effective in breaking projectiles, and causing them to glance off if struck at an angle. Later on experiments were instituted to ascertain what effect masses of coal would have in stopping pro1 In the compound plate, owing to the support afforded by the iron back, a harder steel can be used for the face. Unsupported in this way, a steel plate of the same manufacture would be liable to break up under heavy blows, and hence steel armour is made of somewhat softer—or less brittleI——though tougher material.
For very thick armour we therefore adhered to compound plates, employing steel plates where only a few inches are required.
Twenty years ago we commenced experiments against iron plates 1% in. thick on 6 in. of wood. The' target thus formed was placed at a small angle from the horizontal, and ﬁred at with a 9-in projectile. The protection was insufﬁcient, but succeeding experiments have led to decks of steel 3 in. thick being placed over the submerged portions of vessels. The sides of this armoured deck usually slope down to a short distance below the water line, and are given an additional thickness . This portion of the armoured deck of the ‘ Blake’ and ‘Blenheim’ is 6 in. thick. Advocates of internal armour urge that, for a given weight, more complete protection can be afforded if disposed in this way than if placed externally on the hull.
jectiles, and if it could be ignited by shell. It was found that 20 ft. of coal would stop a 6-in. shot at a short range, and 30 ft. an 8-in. shot, but this would hardly hold good with later guns and steel projectiles. The explosion of common shell did not set the coal on ﬁre.
But this latter result only applies to coal in conﬁned spaces. If placed between decks, it will be more readily ignited. I believe at the battle of Lissa the ‘Palestro’ was destroyed in this way. Her captain, impressed with the necessity of not running short of fuel, had placed a quantity of coal outside the battery. During the action with the Austrian Squadron a shell exploded in the heap and set it on ﬁre. The occurrence appears to have been unheeded at the time,or the crew were too busy with their guns to be called off. When they did endeavour to extinguish the ﬁre, it had gone too far, and while they were thus employed the ship blew up. Few of the crew escaped, but I have been told by an ofﬁcer, who took part in the action in another ship, that this mass of coal was over a magazine, and it is believed that the intervening deck was burnt through until suddenly a ﬂaming mass of coal fell into the magazine. This seems a reasonable explanation, as the explosion was unexpected, or preparation would have been made to abandon the ship. This occurrence shows the danger of carrying extra coal about the decks. It appears to me unwise, also, to place reliance on protection from coal when stowed in its proper place. If it is not to be used, why employ it in preference to armour? When consumed in the legitimate way, which circumstances may render necessary, a vulnerable part of the ship may be exposed to an enemy whom this fuel has assisted the ship to overtake, or from whom it has not sufﬁced to make escape possible.
The disposition of armour and armament adopted in the ‘Inﬂexible’ was followed in only four other vessels, the ‘Ajax,’ ‘Agamemnon,’ ‘Colossus’ and ‘Edinburgh.’ It was considered that smaller battle ships on the same design would be useful additions to the ﬂeet. The ﬁrst two named have a displacement of 8700 tons, and carry in each turret two 38-ton guns, while the maximum thickness of their armour is 18 in.
Being only 280 ft. long, with a beam of 66 ft., their speed is moderate, and for a long time difﬁculty was experienced in steering them. The ‘Colossus’ and ‘Edinburgh’ were great improvements. By increasing the length to 3’25 ft., and the displacement to 9500 tons, a speed of over 15 knots was obtained. Their turrets are armed with 45-ton breech-loaders instead of the old guns, and steel instead of iron is mostly used in the construction of the ships.
But naval ofﬁcers did not approve the departure from the ‘ Dreadnought ’ type. The advantages of placing the turrets en echelon were more fanciful than real, and consequently, when after a lapse of some years there was areturn to double-turret ships, an improved ‘Dreadnought’ design was decided upon. The ‘Trafalgar’ and ‘Nile’ represent this reaction, and as they were only completed ten years ago, it is evident the interval was considerable.
These ships are approximately the same size as the ‘Inﬂexible,’ viz., 12,000 tons at load draught. They have a central citadel, containing the two turrets, placed on the middle line, as in the ‘ Dreadnought.’ Each turret contains two 67-ton guns. Between the turrets, and above the citadel, are mounted eight 45-pounder guns in a battery, thus giving an auxiliary armament which had not been provided in the earlier turret ships. The length of the ‘ Nile’ and ‘Trafalgar’ is 340 ft., of which 230 ft. is protected at the water line with compound armour, varying in thickness from 16 to 20 in. The turrets are covered with similar armour, 18 in. thick.
Machinery of 12,000 horse power gives these vessels a speed of 16 knots. Compared with the ‘lnﬂexible,' they represent a considerable advance in every detail, and are powerful ﬁghting ships. Their only defect, to my mind—independent of the size and cost—is that the guns are not carried sufﬁciently high above the water, and for this reason I have always preferred the barbette system. The turret ship ‘Hood,’ built later, is more than 2000 tons larger than the ‘Trafalgar,’ and represents what appears to be the ﬁnal development of this system, which originated in the cupola ship of Captain Coles. The ‘Hood’ is of similar dimensions to the seven ﬁrst-class barbette ships of the ‘Royal Sovereign ’ type, and only differs in having her heavy guns mounted in turrets instead of en harhette.
Though the general opinion in the navy has been always in favour of double turrets, especially in vessels of large dimensions, suﬂicient success in the production of single-turreted ironclads, as exempliﬁed in the ‘ Rupert’ and ‘Conqueror,’ led to a further extension of this principle in two later ironclads, the ‘Victoria’ and ‘Sanspareil.’ The circumstances attending the loss of the former are well known, but the sister ship remains in the service. She has a length of 340 ft., a breadth of 70 ft., and displaces 10,500 tons. In a single turret forward, protected with 18 in. of compound armour, she carries two 110th guns. In order to supply the deﬁciency of stern ﬁre, which the single turret forward entails, the ‘ Sanspareil’ and her sister had a 29-ton gun mounted aft, working behind a barbette shield. The protection afforded by this arrangement is not great, but considerations of weight doubtless prevented more being done in this respect. To make up for this restriction of the principal armament to three heavy guns, she carries amidships a battery of twelve 6-in. guns and numerous machine guns. Machinery of 14,000 horse power gives this vessel a speed of 16 knots, so that in every respect she shows a marked superiority to the ‘Conqueror’ and ‘Hero.’ She is the only British ship in which a pair of IIO-ton guns are mounted side by side; in the ‘Benbow’ one of these monsters is placed at each end. The ﬁrst—class battle ships of 1889 thus indicate a variety of ideas concerningioffensive and defensive capacity, and a conﬂict of opinions as to the best disposition of armour and armament. We seem, however , to have reached the time when experience with these divergent types will enable us to select the best points in each, and combine them in some type which
shall ﬁnally ﬁll the place of the old three-decker. Whether it will prove equally durable, he who deals with the development of navies half a century hence can alone record. '
The two-decker also had her counterpart in the small ironclads built or converted between 1860 and 1870. Those of about 6000 tons and under were usually termed second class. For a country which has important interests in every part of the world, useful service can always be found for vessels of these dimensions. There were six ships of the same type which for many years carried our ﬂag in the China and Paciﬁc seas. These were the ‘Audacious,’ ‘Invincible,’ ‘Iron Duke,’ ‘Swiftsure,’ ‘Triumph’ and ‘Vanguard.’ The career of the latter was cut short by sinking, after collision with a consort, in the Irish Channel. None of them exceeded 6500 tons displacement, but they carried a powerful battery of guns and 8 in. of armour at the water line. They were, besides, roomy and comfortable vessels, so that, until left behind by the wonderful advance in engines and armament after their completion, they proved admirably adapted for foreign service. They were succeeded by the armoured cruiser in this duty, and therefore the demand for ironclad battle ships of moderate size diminished.
But under the Naval Defence Act two so-called battle ships of the second class were to be constructed, now named ‘Centurion’ and ‘Barﬁeur.’ The length to which we have gone in adding to the size of all classes is strikingly illustrated in this pair. Their displacement on completion was 10,600 tons, which enables them to combine four 29-ton guns—a pair en harhette at each end—ten 45-pounder quick ﬁrers, side armour 12 in. thick, and a speed of 18 knots. A large number of torpedo tubes have also been provided. The 29-ton gun is one that can be worked without the aid of machinery, and hence is not so easily disabled as the larger patterns dependent on hydraulic loading. Its power is about double that of the old 38-ton muzzle-loader, which at one time we considered such an effective weapon. The 45-pounders are placed on the broadside in two tiers, for greater distribution, and to prevent a single shell from disabling two or three of these guns. They have also protection by casemates and stout steel shields. Many are disposed to think that high speed, though essential for a cruiser, is not so requisite in a battle ship. But as vessels like the ‘ Centurion’ and ‘Barﬂeur’ will probably take the place, and do the duty, of armoured cruisers, they would be of little value if unable to proceed rapidly from point to point, or tovcompete in speed with vessels of their own class. For home waters, including the Mediterranean, a moderate speed that can be sustained will sufﬁce.
After dealing with so many ships clad in mail 18 in. thick, it may seem that a protection limited to 12 in. is insufﬁcient, but that amount of hard armour will exclude all but the heaviest projectiles, and something must be left to chance. When wrought-iron was succeeded by a less easily perforated substance we might well have retraced some of the. steps which culminated in 2 ft. of armour. I should be disposed to say that we should never exceed a maximum thickness of 12 or I4 in., but should offer a high premium on improvements in quality by which greater resistance to projectiles may be attained.