Modern ships of war

by Sir Edward J. Reed; Edward Simpson

“The days of the ‘completely protected iron-clad,’ with the broadside armored throughout the length from the upper deck down to five or six feet below the water-line, have long gone by. The ‘central battery and belt’ system has also been practically dropped, whether the battery contained broadside guns or formed a citadel protecting the bases of the turrets. In short, on modern battle-ships there now remains only a narrow belt of armor, rising from five or six feet below the load-line to two or three feet above it. This narrow strip of armor in the French ships extends from end to end, and is associated with a protective deck worked at the height of the top of the belt, and forming a strong roof to the hold spaces beneath. In the English ships of the Admiral class the belt of armor extends somewhat less than half the total length, protecting one hundred and forty to one hundred and fifty feet of the central portion of the ship (in which are situate the engines and boilers), and protecting also the communications from the barbette towers to the magazines. At the extremities of the belt strong armored bulkheads are built across the ships. The protected deck is fitted at the upper edge of the belt over the central portion. Before and abaft the bulkheads, where there is no side armor, the protection consists of a strong steel deck, situated from four to five feet below water, and extending to the bow and stern respectively. Upon this under-water deck are placed coal-bunkers, chain-lockers, fresh-water tanks, store-rooms, etc., the spaces between it and the deck next above being subdivided into a large number of water-tight compartments or cells by means of longitudinal and transverse bulkheads. A water-tight top or roof to these compartments is formed by plating over the main deck-beams with thin steel at the same height above water as the top of the armor-belt. In this manner the unarmored ends above the protective deck are not merely packed to a large extent with water-excluding substances when the vessel is fully laden, but they are minutely subdivided into separate compartments, which can only be thrown into communication with one another by means of very extensive injuries to the partitions.

“In all the modern French ships, as well as in the Admiral class, a light steel superstructure of considerable height is built above the level of the belt-deck; the living quarters of the crew and the stations of the auxiliary armament are contained within this light erection, which also surrounds the armored communications from the barbette towers to the magazines. In this manner a ship with a small height of armored freeboard is converted into a high-sided ship for all purposes of ordinary navigation, sea-worthiness, and habitability; while spaces are provided in which a more or less considerable number of light guns can be fought concurrently with the heavy guns placed in the armor-protected stations. The radical difference, therefore, between the French ships and the Admiral class, independently of other considerations than the armor protection of the water-line, consists in the omission of the side armor at the extremities, and the use instead of the side armor of the strong under-water deck with cellular subdivision and other arrangements for adding to the protection and securing the buoyancy of the spaces at the ends, into which water may find access through the thin sides if they are shot through and seriously damaged in action. If the completely belted French ship has to fight a vessel of the Admiral class, the latter has obviously the greater chance of damage to the narrow strips of the sides lying above the under-water deck before and abaft the ends of the belt. If the action takes place in smooth water, when the ships are neither rolling nor pitching, but are simply in motion, the chances of hitting these narrow strips in the water-line region might not be very great; but it must be admitted that even the lightest guns would penetrate the thin sides of the English ships and admit more or less considerable quantities of water into the ends. If, on the other hand, the fight takes place in a sea-way, with the ships lolling and pitching, then the relative importance of penetration of these narrow’ strips of the ends of the English ships becomes much less, because the belt armor of the French ships will be brought out of water for a considerable length of the bow and the stern by a very moderate angle of pitching, or by the passage of a comparatively low wave, and because rolling motion of the ships will alternately immerse or emerge the belt armor, even at the midships part, where it has its greatest thickness. In fact, as I have more than once said publicly, it is clearly an error to limit criticism to the longitudinal extent of the belt armor in modern ships, and to exclude consideration of the vertical extent of the armor above and below the load-line. Apart from any discussion of the question from the artillerist’s point of view, or any attempt to determine the probability or otherwise of the wholesale destruction of the unarmored portions of modern battle ships by shell-fire from large guns, or by the projectiles from rapid-firing and machine guns, it is perfectly obvious to any one who will examine into the matter that the risk of damage to the light superstructures situated above the belt must be greater than the corresponding risk of damage to the narrow strips of side area exposed at the unarmored ends of the Admiral class, between the level of the belt-deck and the water-line.

“Sir Spencer Robinson, after his inspection of the models shown him at the Admiralty, recognizes the fact that in the French belted ships (of which the Amiral Duperré is an example), if the light sides above the belt-deck are destroyed or very seriously riddled in action, the ship would be capsized in a very moderate sea-way. He further emphasizes the statement that the ships of the Admiral class in the English navy, if similarly treated, would also capsize under the same conditions, and he appears to be surprised at the admission having been made. The fact is that there has never been any assertion that the Admiral class would be safe against capsizing independently of assistance given to the armor-belted portions by the unarmored structure situated above. On the contrary, from the first, in the design of these ships, it was recognized that their stability, in the sense of their power to resist being capsized, if inclined to even moderate angles of inclination, was not guaranteed by the armor-belts. In this respect they were in identically the same position as all other armored ships with shallow water-line belts and isolated armored batteries placed high above water.

“What has been said respecting the Admiral class is this: If the unarmored ends above the protective deck were completely thrown open to the sea, then the initial stability (that is to say, the stiffness of the ships or their power to resist small inclinations from the upright) would still be guaranteed by the central armored portions. So fully did we appreciate the fact that the life of the ship in action (as determined by her power to resist large inclinations) depends greatly upon the assistance given by the unarmored superstructures to the armor-belted parts, that we were careful to make the structural arrangements of the superstructures above the belts such that they could bear a very considerable amount of riddling and damage from shot and shell without ceasing to contribute in the most important degree to the buoyancy and stability.

“There are double cellular sides between the belt and upper decks; the main bulkheads are carried up high above water; hatches and openings are trunked up and protected by coffer-dams. In short, every possible precaution is taken to subdivide into compartments, and thus limit the spaces to which water can find access when the outer sides are penetrated or shattered, as well as to facilitate the work of stopping temporarily shot-holes in the sides.

“Now, without in the least intending to discredit the work of the French designers, I have to state that no corresponding or equal precautions have been taken in the portions of their ships lying above the belt-decks. And the absence of these features in the French ships is a great relative advantage to the English ships. Of course there is nothing to hinder the French from imitating our practice, but they are content to take the risks involved in a simpler construction, and in so doing they show their practical disbelief in the doctrine of armor-protected stability. I am aware that some eminent authorities do not concur with this view, and maintain that stability and buoyancy should be guaranteed by armor. To this point I will revert hereafter, but for the present I am content to say that, as between the French ships and the Admiral class, the most serious risks of damage by gun-fire in action are of the same kind, and, practically, are not affected by the shortening of the armor-belts in the English ships.

“Next I would refer to the differences which are undoubtedly involved in shortening the belts of the English ships. In the first place, by dispensing with the side armor towards the extremities a very considerable saving is effected in the weight and the cost of the armor fitted to the ships. Mr. Barnaby has recently given an illustration of this, where a ship, in other respects unchanged, has to be increased from 10,000 to 11,000 tons in displacement in order to carry the shallow armor-belt to the ends. In the Collingwood herself quite as large a proportionate increase of size would be involved in having a thick armor-belt from stem to stern. This saving in weight and cost of armor might, of course, be purchased too dearly, if dispensing with the armor involved possibly fatal risks to the ship. However the result may be attained, there is universal agreement that a ship-of-war should have her buoyancy, stability, and trim guaranteed as far as possible against the effects of damage in action. Now, in the Admiral class this matter was very carefully investigated before the design was approved. In order to prevent derangement of the trim of the vessels by penetration of the light sides above the protective deck at one end, arrangements were made in the design by means of which water can be introduced into the spaces occupied by coal-bunkers, etc., before the ships go into action.

“The extent to which water may be introduced is a matter over which the captain would necessarily have control. But even if the whole of the unoccupied spaces were filled with water, the increase in draught would not exceed fourteen to eighteen inches, and the loss in speed would not exceed half a knot. If only the coal-bunkers were flooded as a preliminary to action, the chance of any serious disturbance of trim, and consequent loss of manœuvring power or speed by damage to the light sides above the protective deck and near the water, would be very small, and the ‘sinkage’ of the vessel would be decreased considerably. But taking the extreme case, with the ends completely filled and a sinkage of fourteen to eighteen inches, a ship of the Admiral class would go into action with practically her full speed available, and with her ends so protected by under-water deck and the water admitted above that deck that damage to the thin sides by shot or shell penetrating at or near the water-line would not produce changes of trim or alterations of draught to any greater extent than would be produced if the armor-belt had been carried to the stem and stern. Nor would the admission of water into the ends render the vessel unstable.

“It has been urged that the sinkage due to filling the tank ends with water is a disadvantage, because it brings the upper edge of the belt armor in the Admiral class about fourteen to eighteen inches nearer the water than the upper edge of the belts of the French ships. If the greatest danger of the ships was to be measured by the smallness of their ‘reserve’ of ‘armor-protected buoyancy’ (that is to say, by the buoyancy of the part of the ship lying above her fighting water-line and below the belt-deck), then the Admiral class would not compare favorably with the fully belted French ships. But I have already explained that this is not the true measure of the greatest danger arising from the effects of gun-fire, and that it would be a mistake to assume that in either the French or the English ships the armor-belted portions of the vessels guarantee their safety when damaged in action.