Before entering upon a discussion of the uses of armor and the considerations which should govern its distribution in ships of war, it will be well to briefly outline the history of its introduction and development and describe modem methods of its manufacture.
It was the introduction of shell-guns which rendered wooden walls, and even iron hulls without armor, impracticable for war vessels, and the signal instance of their effect in the annihilation of the Turkish fleet at Sinope first showed the necessity of providing some protection against their destructive fire. To John Stevens, of Hoboken, N.J., belongs the credit of originating the idea of applying armor to the sides of ships, but the French first gave this idea practical shape in the floating batteries which, on October 17, 1855, silenced the Russian forts at Kinburn. The cuirass of ancient times was restored, but instead of defending the breasts of single warriors from hostile spears, it was expanded over whole frigates—their armament, men and machinery, and thickened to resist shells and even solid shot.
But the superiority of the defense was short-lived, and the introduction of new weapons of attack and the continued advance of artillery in weight and power soon forced a corresponding development of armor.
For some years manufacture of armor was limited to plates of small area, and imperfect welds and steely spots, as well as great irregularity in quality, were necessary evils owing to imperfect appliances for the production of thick plates. Laminated plating, when tried, was found greatly inferior to the same thickness in a single plate. In 1859, however, armor manufacture had so far
developed that French 4 ¾-inch plating proved superior to the attack of the 68-pdr., then the most powerful naval gun, and in 1860 the English report "vessels clothed in rolled iron plates 4 ½-inches thick are to all practical purposes invulnerable against any projectile that can at present be brought against the mat any range." But the general adoption of rifled guns on the Continent and the introduction of the 11-inch and 15-inch smoothbore guns in the United States called for renewed exertions on the part of the armor makers, and in 1867, it being still impossible to produce plates of reliable quality more than 6 or 7 inches thick, the plate upon plate system, in which several thick plates were superimposed, was tried and proved superior, in the then state of the art, to the solid plate of equal thickness. In 1868 plates over 8 inches thick were tested, and in 1872 12-inch plates were tested both in England and Prussia, and, though of good quality, were hardly a match for the guns brought against them. Such had been the development of the artillery with which armor had to contend that while, as late as 1863, 4 ½-inch plating made a ship invulnerable, in 1868 it took 9-inch plating, and in 1872 a 12-inch plate was pierced on the firing ground. With the introduction of 12-inch plates the limit of regularity in manufacture with wrought iron seemed to be reached, and the cost of the plate upon plate system, owing to difficulty in making the plates fit each other, led to the trial and adoption of the sandwich system, in which layers of wood separate the two or more plates making up the complete target. The first application of this system was to the English ship Dreadnaught, whose turrets, built up of two 7-inch plates, separated by 9 inches of teak and secured to a backing of 6 inches of teak and two ¾-inch skin plates, were considered more than a match for the 12-inch rifle. But the advent of the14 ¼-inch Krupp rifle in 1875 and the 81-ton Woolwich gun in 1876 marked the final supremacy of the gun. Wrought-iron armor had now reached its highest development in the Inflexible, whose armor consisted of two layers of 12-inch plates with 11 inches of teak between, backed by 6 inches of teak and two 1-inch skin plates. Simultaneously with the adoption of this armor disposition the Italian government, desirous of building the most powerful ships in the world, called for competitive tests of 22-inch armor, and two French and two English firms having- submitted plates, in 1876 took place the famous Spezzia trials which revolutionized armor manufacture in Europe. The plates submitted were solid wrought iron, sandwich wrought iron, sandwich with wrought-iron face plate and cast-iron rear plate, and solid steel, the latter made by Schneider & Co. of France. The guns used were the 10-inch and 11-inch! Woolwich rifles and the Armstrong 100-ton gun. The Italian commission condemned the types containing cast iron as of relatively feeble defensive qualities; stated that the remarkable advantages realized with the single plates left no doubt of the superiority of this disposition over the sandwich, and concluded that the most advantageous disposition of armor was embodied in the solid steel plate, this having kept out all shot, although wrecked thereby, while the iron targets were pierced by the shot from the 100-ton gun. Thin steel plates and iron plates faced with steel had ere this been tried in England with doubtful success, but it was now recognized that the day of wrought iron had passed, and attention was at once turned to the production of armor having the resisting qualities of the Schneider plate without its brittleness. In August, 1887, the first of what are known as compound plates was tested at Shoeburyness, England. This plate, made by casting a steel face upon a wrought iron back and rolling the whole to a thickness of nine inches, was tested with the 7-inch rifle, the penetration being but 3 1/8 inches, whereas in a wrought-iron plate it would have been fully 8 inches. In another year 9-inch compound plates, now adopted for the Inflexible's turrets, resisted the 9-inch rifle, so rapid was the development of the new system, and in 1880 the manufacture of both compound and steel armor had so progressed that they were brought into close competition. In 1882 the Italian government again invited armor makers to submit plates to test in order to determine the best system for use on the Lepanto; and Cammel & Co. and Brown & Co., of England, the foremost makers of compound armor, and Schneider & Co., of France, the leading makers of steel armor, each submitted a plate 18.9 inches thick. Two shots from the 100-ton gun wrecked each compound plate, while the steel plate, after three, still covered the greater part of its backing, the commission concluding that the Schneider plate was superior to the compound plates and better adapted to protect a ship's side. Steel plates were not always victorious, however, for in several trials, notably that at Ochta, in 1882, the compound plate proved the better, and the less cost and more rapid development of this system in England led to its exclusive use there and its general adoption on the Continent during the next ten years. The demand for steel armor was, however, sufficient to continue its development, and its increasing superiority was so demonstrated by various tests that when the United States, in 1886, had before it the task of domesticating the manufacture of heavy armor, the decision as to the preferable material was not doubtful, and steel armor was ordered for all the armored ships then authorized by law. In 1890 the first public trial of a new material for armor—steel alloyed with nickel—took place at Annapolis, Md., a competitive test of a Cammel compound, a Schneider steel and a Schneider nickel steel plate being held by the Navy Department. The compound plate proved inferior in a marked degree to the others, and the nickel-steel showed a remarkable resistance to cracking. In the same year a steel plate hardened on one face by a process of superficial carbonization was also tried at Annapolis and showed phenomenal resistance to penetration. In 1891 the U.S. Navy Department tested three plates made by the Bethlehem Iron Company of Pennsylvania by the usual forging process, and three made by Carnegie, Phipps & Co., of Pennsylvania, by rolling in a heavy plate-mill. Five of these plates were of nickel-steel and three had been surface-hardened, or Harveyed, as it was called, from the inventor of the process. This test demonstrated that good armor of moderate thickness can be made by the rolling process, a fact of considerable importance—that the nickel-steel plates made in the United States were markedly superior to any armor that had been publicly tested abroad, and that the process of surface-hardening offered a probable means, after some difficulties were overcome, of greatly increasing resistance to perforation.
As a result of these trials, our Government at once adopted nickel-steel Harveyized plates for the armor of all its ships, and within a very short time the use of surface-hardened steel, either simple or nickel, became general abroad, compound armor going out of use entirely.
The following is a brief description of the method of manufacturing armor used in the United States. The ingot, of approximately rectangular cross-section and about twice the weight of the finished plate, is made of open hearth steel, sufficient nickel being added to the furnace charge to produce about 3 ¼ per cent, in the final cast. After cooling, the ingot is stripped, reheated and forged to the required dimensions, the first operation being forging the upper end into a porter bar for handling, and the entire forging operation usually requiring several heats. Either an immense hammer or a hydraulic press may be used for forging, but the latter is considered preferable, both as regards manufacturing economy and superiority of product. The Bethlehem Iron Company have both a 120-ton hammer and a i6,ooo-ton hydraulic forging press; the Carnegie Company have a similar press and rolls, the latter being used at present only for thin plates (9 inches or less in thickness).
After forging, the upper end of the plate is cut off under the press or hammer, and the remainder, after cooling, is trimmed to size by a saw or planer. It is then placed in the Harveyizing furnace with its back and sides well protected by refractory materials and its face covered with the carbonizing mixture, is heated to a high temperature and allowed to soak for several days. When the hardening material has penetrated sufficiently into its face, the plate is removed from the furnace. It is then reheated, bent to the required curvature under the hydraulic press, again heated and allowed to cool slowly to remove the strains caused by bending. Occasionally, when the curvature is slight, plates are bent before being Harveyized; usually they are bent after Harveyizing, though before tempering. The Harveyizing operation merely consists in putting carbon into the face of the plate, and it is not until after the tempering process that this face becomes hard and brittle.
The next operation consists of heating the plate and chilling its surface with a spray of cold water, which hardens the highly carbonized face, but leaves the body of the plate still soft.
Finally the curvature is rectified under the press at a low temperature, not sufficient to soften the hard face, and the bolt holes are bored and tapped. The face of a Harveyized plate, after tempering, is so hard as to resist any tool, and when bolt-holes are required to be bored in the hard face for structural purposes an ingenious process of annealing, or softening, by an electric current has been devised and is in successful use.
Armor was first applied to wooden ships, but when iron and steel ships succeeded these it was found necessary to interpose a certain thickness of wood between the skin plating of the ship and the armor to decrease injury to the ship's side from impact of shot, and to provide a surface that could be trimmed to exactly fit the plates as manufactured. This backing is of oak or teak, and in modem ship design is usually of moderate thickness. At first much trouble was experienced with fastenings, the through bolts originally used causing leaks and snapping at the bottom screw-thread when the plate was struck. These defects were remedied by using bolts like wood screws extending not quite through the backing. The bolts now used are of forged steel, pass through the skin plating and backing and screw into the plate from two to three inches; they have shanks of reduced diameter to prevent breaking at the thread, are packed with hard rubber to prevent leakage around them, and have rubber washers under the nut heads. With steel armor one bolt is used to about every 4 ½ square feet of plate, and the diameters vary from 1 ½ inches for thin plates to 3 ½ inches for thick plates.
Whatever may have been the case in the past, it is safe to say that with the armor in present use wooden backing adds nothing to the resistance, and its only advantage is the supposed distribution of the shocks of impact over a large area of the plating behind armor due to the close fitting surfaces rendered possible by its use. It is to be hoped that the use of wooden backing will be entirely abandoned in future construction.
Putting aside for the moment the consideration of the increased resistance resulting from the surface-hardening processes now in general use, let us see what has been the outcome of the thirty years' development of guns and armor since 1860, when the 4 ½-inch iron plate was declared invulnerable to any gun afloat. To-day such a plate would be easily perforated by the projectiles of the 4-inch gun at 2000 yards' range, and at pointblank by the 6-pounder, and the best nickel-steel armor-plate must be almost twice the calibre of the gun attacking it in order to resist perforation at point-blank with normal impact and the best quality of armor-piercing shell. Even at fighting ranges the heaviest armor now in use will be no match for the 13-inch gun, provided the impact is nearly normal.
Five years ago the gun seemed to have finally and definitely attained supremacy, when suddenly and most unexpectedly the surface-hardening process was found practicable, and at once armor development appeared to take an immense stride forward. A 6-inch plate so treated has shown itself invulnerable to the attack of the 6-inch gun, a 14-inch plate to the lo-inch gun, and a 17-inch plate to the 12-inch gun. What is the cause of this change in the relative powers of attack and defense, and is the present relation likely to be an enduring one? I believe not. Years of development resulted in the production of forged steel shell which, being capable of withstanding the tremendous strains of impact upon steel plates without injury or practical distortion, delivered the entire energy of their blows upon the plates and pierced them. These projectiles, when called upon to meet the still greater strains of impact upon hard-faced armor, broke into fragments, dissipating a large part of their energy in heat and useless work, and consequently failed to penetrate. Only when their velocity was so great as to cause their broken fragments to tear through was the Harveyed armor pierced. But already we are perfecting our projectiles to meet the new demands, and there is no reason to doubt that in the course of time they will be produced of such a quality as to endure impact at high velocity upon the hardest surface. Experimental shell have been tested at the Indian Head Proving Ground which passed through Harveyed plates without distortion, and it has been shown, in my opinion, that with such projectiles the hard-faced armor is not greatly more resisting than the homogeneous nickel-steel armor it has superseded.
But if guns now overmatch all practicable armor, and continue to progress as they have in the past, more rapidly than armor, will not they, or even new weapons of offense now unknown, cause the use of armor for ships to be abandoned and become obsolete, as the invention of gunpowder drove out of use armor for men? This is a serious question, usually answered in the affirmative by civilians and often by military men, and merits consideration, for if armor is ever to be abandoned, now is the time for us to give it up and plan our new ships on other lines.
Two arguments are commonly advanced in favor of the opinion that armor for ships of war will, in course of time, become obsolete. The first is based upon the supposed analogy of the case of ships with that of men—since the development of small arms resulted in the abandonment of armor for men, why will not continued advance in the power of ordnance render it useless to armor ships? The answer is simply that the analogy is a false one; the strength of the individual is limited, while the carrying power of ships depends only upon their size and may be made as great as we please. Moreover, a man being far more highly organized than any work of human hands, is put "hors de combat" by a wound in any part of his body, and consequently must be completely covered with armor to be really protected; while a ship, over a very large percentage of her area, may be pierced through and through without suffering serious damage, and needs protection only over a few vital parts. Lastly, even if the power of guns were so great as to render it useless to attempt to keep out their armor-piercing projectiles from any part of a ship, still an enormous advantage would result from the use of armor which kept out explosive shell. A solid bullet is enough if it hits a man, but a great many solid shot of the largest size may pass through a ship without putting her out of action. A distinguished British naval officer in expressing his contempt for all sorts of pounders, from i8's to 68's, when firing solid shot, added, "but, for God's sake, keep out the shells," and his remark expressed the truth, learned from actual experience of war, that the highest and real function of armor is to keep out explosive shell.
The second argument against the continued use of armor for ships is that the approaching advent of the "high explosive shell" will render it worse than useless, the enormous masses of explosive to be hurled against ships by the guns of the future being sufficient to blow in their sides and destroy them without penetration of their armor. Now, that we can, to-day, throw large charges of high explosives from our ordinary guns and detonate them on impact I do not doubt, but what I do doubt and deny is the alleged effect of such detonations. In order to give projectiles sufficient flatness of trajectory to enable us to have any practical chance of hitting an enemy's ship, we must make their walls of considerable thickness to withstand the strains of firing, whether from powder guns or air guns, and the effect of the detonation of high explosives is so local in its character that when such shell strike against armor the result is the complete shattering of the shell with little or no other effect. On the other hand, if we make the shell strong enough to pierce armor, and use delay-action fuses to detonate them, the amount of the explosive which can be put into the largest shell is too small to do great damage. In fact, as far as the experiments we have thus far made go, powder shell are more destructive than those filled with other explosives, and the idea of blowing in the side of an armored ship by the explosion of a shell is, in my opinion, a fallacious one.
But even allowing that in time to come the best armor will not only be unable to keep out the solid shot of large guns, but also their explosive shell, still a little consideration will show that by keeping out projectiles of the lesser calibres armor will render service of immense value.
Taking, for example, the proposed battery of the new battleships, four 13-inch, four 8-inch, fourteen 5-inch rapid-fire and twenty-six smaller rapid-fire guns, and assuming the turret guns to be in use constantly, while the rapid-fire guns, mounted in broad side, are in use only half the time, and allowing that the rate of fire is once every five minutes for the 13-inch, once every two minutes for the 8-inch, three times a minute for the 5-inch, and four times a minute for the smaller rapid-fire guns, we find, by a simple calculation, that of all the projectiles fired in any period of time only 6/10 of one per cent, will be of 13-inch calibre, 1 6/10 per cent, of 8-inch calibre, 16 5/10 per cent, of 5-inch calibre, and 81 3/10 per cent, of the smaller calibres. In other words, 3-inch armor will keep out at least 8 3/10 per cent, of all projectiles fired by one battleship against another, 6-inch armor will keep out at least 98 per cent, and 12-inch armor will keep out at least 99 4/10 per cent. When we consider the fact that most impacts will not be normal and that the range will usually be considerable, we may safely say that under any probable future conditions armor of about 7-inch thickness will keep out 98 per cent, of all projectiles fired against it.
Assuming, then, that it is at least probable that armor will continue in use indefinitely on ships of war, let us consider somewhat how it can be distributed to the best advantage.
The displacement, and, consequently, the weight-carrying capacity of ships, being limited by practical considerations of expense and handiness, it is apparent that a defensive covering of even moderate thickness cannot be spread over their entire area, but that It must be limited to those portions of each ship which it is of vital importance to protect. It is of the first importance to preserve the stability of a ship by preventing such extensive water-line damage as to cause her to sink or capsize. Next in importance is the protection of the propelling machinery. Lastly, the offensive weapons of a ship, her guns, with their machinery and crews, must be as far as possible guarded from injury. With all power of offense destroyed, a ship may be saved, if her stability and propelling machinery are intact; with offensive weapons powerless and machinery disabled, the crew at least will escape destruction, and the fortunes of war may even cause the rescue of the ship herself from the hands of the enemy, provided she continues to float; but a sufficiently effective attack upon the stability of a ship must result in a total loss of ship, crew and all.
I do not mean to imply that floatability is to be absolutely assured first, then safety of the propelling machinery, and, lastly, that of the battery; this is a question of relative protection only. What I mean is, that in distributing our protection we should endeavor to, first, make it unlikely that our ship will be sunk in action; second, make it unlikely that her motive power will be destroyed; third, make it unlikely that her offensive power will be greatly weakened. The bigger the ship, the more unlikely all three should be. As to the prime importance of preserving floatability I think there can be no question, but the relative importance of motive and offensive powers seems somewhat doubtful. A total loss of maneuvering power is extremely unlikely under any circumstances, on account of the subdivision and under-water position of propelling machinery; but so also is the complete silencing of the battery very unlikely. When, however, we consider the fact that in the past ships have always been defeated by the reduction of their offensive powers, due to destruction and demoralization of their personnel, I think it fair to conclude that, although a moderate protection of motive power is only second in importance to the protection of stability, yet, after this is assured, then the protection of the guns and their crews becomes the more important. It must not be forgotten that there is an essential difference between the case of a whole ship, with men and machinery distributed throughout its length, and the small turret or casemate into which the vitality of a ship is crowded. "It is the thin line instead of the close column." In the modem battleship, where the offensive power is practically concentrated in two gun positions, it is more important to prevent any projectile from entering these spaces than it is to protect the whole length of the machinery space. If a projectile enters the turret it will probably put out of action, practically, one-half the ship's battery, but many projectiles may enter the machinery space without destroying the motive power. Moreover, the propelling machinery—boilers, engines, shafting, screws and rudder—being almost entirely below the water-line, the armor which is applied to the protection of the stability serves a double purpose, protecting the machinery as well.
Leaving out of consideration the class of so-called protected cruisers, in which an armored deck, flat amidships and sloping off on either side and at both ends below the water-line, affords the sole protection to the machinery, we find in almost universal use in armored ships a heavy armor belt, partially submerged, and of length varying from half that of the vessel to her complete length. This belt is usually composed of tapered plates, the below water parts thinner than those above, and the plates becoming thinner as bow and stern are approached. When the belt is not complete an armored deck is fitted, sloping down forward and aft from its ends, which are connected by thwartship bulkheads.
The armor protection for the offensive weapons consists of turrets and barbettes, with ammunition supply tubes, and of casemates.
Besides the above, guns in the open are usually fitted with light shields, and the between-decks portions of the smokestacks are sometimes armored.
There being but a limited weight of armor allowable, it is evidently a question of great importance to properly proportion it so that the most advantageous distribution of the protection may result. Yet when we examine the plans of armored vessels built or building in our own and foreign countries, we cannot fail to discover that in many instances this important subject has been given too little consideration. When, for example, we see ships so designed that they will probably go into action with their armor-belts completely submerged; when we see them with heavy armor about the gun supports and with less, or even none, to protect the guns and their crews; and when, the most frequent of all, we see what may aptly be called "fictitious protection," such as thick conning towers which the impact of a heavy projectile would tear from their flimsy fastenings, and heavy armor plating of so little width that it would yield by being split long before it was pierced, then it becomes apparent that the subject of the proper distribution of armor protection needs discussion.
The following are the principles upon which I believe the armor distribution of battleships should be governed, with the arguments in favor of them.
(1) The position of the belt should be fixed with reference to the deep-laden draft of the ship, not her light draft. The practice of placing the belt with three-fifths or two-thirds below water at what is called normal draft is bad, because when a ship goes into action she will probably be laden down with extra ammunition and carry every pound of coal possible. Everything tends to sink your belt lower, and, if too low, you cannot raise it, but if too high you can always sink it to the proper place by letting in water.
The width of belt we have adopted for our battleships is 7' 6", and hitherto we have placed the belt so that at what is called "normal," but is really "light" draft, the upper edge is 3' 0" above water. Now the Indiana and class, with bunkers full (1640 tons of coal), draw 27'.15, or 3'.15 more than when at so-called normal draft (400 tons of coal). Consequently, if they go into action with bunkers nearly full and no other excess of weights, their belts will be only 1' above water. But when their turret guns are trained to one side a heel of 3° results, and this will submerge their belts nearly a foot on the engaged side. In the new battleships balanced turrets will be used, and, consequently, there will be no heel due to training the guns; but it is proposed to place the belt 3' above water at light draft (500 tons), which would put it only 1' 6" above with full bunkers (1300 tons). The Bureau of Ordnance wishes to raise the belts 1', so as to be 2 6" above water at heavy draft. The real questions are: 1st, What is the best position for the belt when the ship goes into action, and, 2d, what will the draft probably be when the ship goes into action? Now it seems to me that to have the belt 2' 6" above water and 5' below is better than 1' 6" above and 6' below, but in any event, having once decided on the best position with reference to the water-line, then we should place the belt so as to be in that position when the ship is deep-laden, for she is much more likely to go into action deep-laden than light, and being light she can be sunk deeper by admitting water to her double-bottom compartments, increasing her stability at the same time; whereas, being deep, she cannot be lightened.
(2) Belt armor should be thick enough to keep out all explosive shell. This will probably require a thickness equal to the calibre of the largest guns brought against it. Over the machinery space it should be of uniform thickness or very slightly tapered. Great taper weakens a plate in greater proportion than the saving of weight. Complete belts are not specially necessary, for the ends of the ship will get few hits compared with the central portion; there is little to protect at the ends, and water-line damage there is of comparatively small importance. The width of the belt should be at least seven times the calibre of the largest gun likely to be brought against it. The new English battleships (Magnificent class) are to have only 9-inch side armor, but I think this hardly sufficient. Our 13-inch common steel shell will carry a bursting charge of 60 pounds through that armor if they hit normally.
(3) The heavy guns should be protected by turrets and their supports by barbettes. The thickness of the turret armor should be greater rather than less than that of the barbettes. Both should be thick enough to keep out explosive shell, but the turret should, if possible, be thick enough to keep out all projectiles. The armor around the guns should be thicker than the side armor, because the turrets are more likely to be hit than the belt, since they always offer themselves to normal impact whatever the enemy's position, while the belt will practically always be at an angle to the line of hostile fire, and since the effect of a projectile which gets into the turret is likely to be far more serious than one which gets through the belt. A solid shot through the side or barbette armor is extremely likely to do no further damage; it will probably put a turret out of action. The following examples may be cited as illustrating this. At the battle of the Yalu the Itsukushima was struck by a 21 cm. (8-inch) shell, which passed through the coal bunkers containing 30 tons of coal, about 12 feet thick, through a ½-inch bulkhead, and exploded in the engine-room gallery, a space about 15 feet square. Six large fragments passed through the port bulkhead, making holes one foot in diameter, and numerous smaller fragments passed downward into the engine-room, killing one and wounding another man, but doing no other injury. A 6-pounder shell exploded in the engine-room of the Hashidate without doing any injury. Either of these projectiles exploding in a turret would almost certainly have done serious damage.
(4) Ammunition tubes, or other means of protecting ammunition in transit from magazine to turret, are worse than useless except in the case of the heaviest guns, where any damage to the mechanical hoists would put the guns out of action. Whenever ammunition can be hoisted by whip, a clear passage, with no enclosing walls, is the best. Many of our ships are designed with ammunition hoists enclosed by steel tubes from one inch to two inches thick. A projectile striking one of these tubes would almost certainly bulge it in or distort it so as to completely shut off the supply of ammunition. Whereas, if there were no tube, the projectile could, at worst, cut the whip or other hoisting apparatus, a damage easily repaired, or, as a remote possibility, strike the ammunition in transit, an occurrence not likely to result in any serious consequences.
(5) Heavy conning towers, also, are worse than useless. The impossibility of getting a commanding view from such a station would certainly prevent the captain of a ship from occupying the conning tower in action. I would suggest a moderately thick armor plate, placed fore and aft, and well braced from each side, as a shield, on either side of which the commanding officer might stand. A speaking-tube, with a branch on each side of the shield, and leading to a distributing chamber below, would afford a convenient means of communication to all parts of the ship, the captain's orders being received at the central station and thence transmitted as required. Perhaps an armored well below the bridge would serve even better, orders by word of mouth being there heard and distributed by voice-tubes or telephones.
(6) The secondary battery of 4-inch or 5-inch rapid-fire guns should be in an armored casemate between the main turrets, and should be protected by at least four inches of armor. This thickness will keep out most explosive shell and all projectiles from small rapid-fire guns.
(7) Between the casemate, or armored superstructure, and the thick armor belt is a wide space which it is now usual to protect against explosive shell by the use of 4-inch or 5-inch armor. I have some doubts as to the advisability of this practice. Certainly the Indiana class and the Iowa designs, where four inches of armor is applied over this space, while the casemate is unprotected except by 4-inch sponsons where the guns are mounted, are not good. Much better would it have been to have used this weight of armor for a complete covering of the superstructure.
In the new battleships where the superstructure has 6 inches of armor all over, it may be very well to cover the space above the heavy belt with 5-inch armor, but I am inclined to think that an addition to the height of the thick belt would be better.
As an example of armor distribution, the following table of weights for the Indiana class and the Iowa may be interesting:
Indiana | Iowa | |
Protective deck | 534 tons | 562 tons |
12-inch and 8-inch gun positions | 1556 tons | 1440 tons |
Side and bulkhead | 1085 tons | 1045 tons |
Protection to secondary battery | 38 tons | 39 tons |
Conning tower and tube | 55 tons | 56 tons |
Cellulose | 55 tons | 65 tons |
Bolts and backing | 201 tons | 168 tons |
Total Weight for Protection | 3524 tons | 3375 tons |
149 tons difference |
It is curious to note the difference in these designs, and, from my point of my view at least, the sacrifice of real to apparent advantages in the latter design.
The Iowa, with the same coal supply on board, is of 700 tons greater displacement than the Indiana; she carries 149 tons less armor (2 inches less on her barbettes and 4 inches less on her belt) and she has 12-inch guns instead of the 13-inch of the Indiana, and, as a result of these great sacrifices, she can steam one knot faster. In order to add a knot to her speed she is made 700 tons larger and her offensive and defensive powers are greatly reduced. The curious arguments made in favor of the Iowa design were: 1st, “Progress in ordnance had resulted in such an increase of the power of guns that the only moderate calibers were now necessary to overcome any armor,” and 2d, " The recent developments in armor manufacture had resulted in such an increased power of resistance that it was safe to reduce its thickness." We had succeeded in making our guns so powerful that they were irresistible, and our armor so strong that it could not be overcome.
Fortunately, wiser counsels now prevail and the new battleships are to have 13-inch guns, and, in any event, a better armor distribution than we have had before, though the exact arrangement is still in doubt. The following table gives the approximate distribution of armor weights:
Protective deck, 556 tons
13-inch and 8-inch gun positions, 1600
Side and bulkhead, 1083
Protection to auxiliary battery, 381
Conning tower and tube, 57
Cellulose, 60
Bolts and backing, 235
Total weight of protection, 3982
It will be observed that, practically, all the additional weight of armor, about 400 tons, is to be devoted to the protection of the guns and personnel.
When we consider the armoring of ships smaller than the battleships, another problem presents itself. Only a moderate amount of protection can here be given, and, at the same time, only guns of medium calibre will be found on an enemy of the same class.
On the assumption that such ships will be armed with either six or eight 8-inch guns in turrets, and with a large number of 5-inch rapid-fire guns in broadside, which would be the most effective battery for use against another lightly-armored ship, we have to consider how to protect such a battery, and what the relative importance of the protection of stability, propelling machinery and battery is in such a ship. On the New York and Brooklyn we have devoted almost all our armor weight to a protective deck six inches thick on the slope, a belt four inches thick covering the middle length of the water-line, the 8-inch guns being in turrets of about 6-inch thickness, and the rapid-fire guns having nothing but shields.
This seems to me an unsatisfactory distribution. Would it not be better to trust to the armored deck with cellulose and coal above it for protection both to stability and machinery, and give 4-inch protection to the battery deck? At present, a sufficient number of 6-pounders on an enemy would make the New York or Brooklyn's gun-deck untenable, while their machinery is reasonably safe against the guns of a battleship. An armored cruiser may have to fight a battleship, but her main object is to exceed in power other armored cruisers, and this can only be when her defensive powers are not only proportioned to her offensive, but when they are properly proportioned among themselves.
And now, in conclusion, I wish to say a word about the importance of large calibre in the attack of armor. You may go on increasing velocities and improving projectiles as much as you please, but you can never get the terrible destructive effect of the large shell from a small one. This is so in the case of explosive shell, but it is even more so with armor-piercing shell, which are practically solid shot. The cracking and shattering effect upon the armor plate and the tearing, splintering and rending of the structures behind armor produced by big shell must be seen to be appreciated. There are many advocates of the restriction of calibre of naval guns to 12-inch, or even lo-inch, and you often hear it said, or read in books and papers, that the "best naval opinion" is for keeping down calibre. I beg of you not to believe this. The circumstances of actual fighting at sea add immensely to the effectiveness of armor and reduce greatly the power of guns in comparison with their relative values on the proving ground. The 13-inch gun is necessary for our battleships, and it is a concession to prejudice that restricts calibre to that size. The increase of one inch from 12 inches to 13 inches seems small, but it means an actual increase of energy of one-third, and a sight of the results of firing the 12-inch and 13-inch guns at the same plate would convince any one of the great value of this increase. Happily it has been settled that the new battleships are to have the 13-inch guns and not the 12-inch, and I do not hesitate to predict that if we ever have a naval war with a first-class power we will rather regret not having installed larger guns than the reverse.