THE COMPOSITION AND ARRANGEMENT OF SHIPS' BATATERIES.[*]
One of the most interesting and important ordnance questions to-day is the determination of the character and disposition of battery most advantageous for the various classes of ships of war.
In the matter of gun construction, progress for some years has been only in the perfecting of details. The breech-loading rifle, built up of forged steel parts, or wire-wrapped, is not likely to be superseded by any other weapon. Improvements in quality of materials may enable us to make guns lighter, and new methods of construction may enable us to make them cheaper, but no radical changes are likely to be made, and it is the perfecting of such details as the firing mechanism and sights that now principally occupies the attention of the ordnance officer.
Gun mountings, too, have been improved to the point where but little further advance seems possible. The balanced gun mount, with hydraulic recoil check and spring return, leaves little to be desired.
As far as ammunition is concerned, great progress has been made in increasing the efficiency of projectiles and fuses, and further progress is being made all the time, but this progress consists in the improvement of what we have, not in the invention of new things. The introduction of the so-called smokeless powders was, indeed, a radical change, putting at the service of artillery the most powerful explosives known, but another similar step in advance can only result from the discovery of an entirely different type of explosive from any now known to chemists.
The very fact that all civilized nations use practically the same guns, mounts, projectiles, powder, etc, is a sufficient guarantee that oar ordnance material is constructed upon principles of sound reason.
When, however, we consider the composition and disposition of ships' batteries, we find not only the greatest divergence in the practice of different nations, but radically different views adopted in the various designs of each particular navy. It would appear beyond doubt that for every special type of war-ship one particular battery is best suited, and that a little study of the uses to which a given type is adapted, and of the purpose for which the type was developed, would result in at least tolerable unanimity of opinion as to the most efficient armament for that type. The trouble has been that this matter has received of late years too little attention, and its determination has been too much in the hands of people whose interests are enlisted in the development of other features of ship design. The reputation of a ship designer and the profit of a shipbuilder are not affected by her greater or less efficiency as a fighting machine to the same extent as they are by her greater or less speed. The faster a ship, the more widely advertised to the world are her designer and builder; the greater the percentage of displacement allotted to hull and machinery and fittings, the larger the margin of profit on the contract. The wide-spread craze for fast unarmored ships was, in my opinion, born of the personal interests of shipbuilders, and has lived, and even flourished, largely because the military branch of naval service has been excluded from its proper predominating place in the councils which determine the general features of ships of war.
Let it once be recognized that the object of a man-of-war is to win battles, and that battles are won by fighting, not by running, and more regard will be paid to the selection and arrangement of weapons, and the less will offensive power be sacrificed to speed. I have never been able to see what material advantage the commanding officer of a ship would derive from her possession of greater speed than an adversary, nor am I inclined to believe that the commander-in-chief of a fleet will be able to use to any great advantage the high speed of his vessels in an action. Of course, speed is useful as a means of escaping or forcing an engagement, and as giving the power of rapid concentration or of striking suddenly at a distant object; but when the moment of actual fighting arrives, superiority of speed will weigh as nothing in comparison with superior armament. In the consideration of this subject, moreover, one point has generally been overlooked, and that is, that in many, if not all, modern fast cruisers there is not berthing space for a crew sufficient in numbers to maintain both speed and rate of fire at their highest during an engagement. If sufficient engineer force is employed to keep steaming power at the top notch, the fire of the guns will inevitably slacken at the first serious casualty or from the fatigue of the first few moments of action, relief crews being wanting. The popular idea seems to be that the battle may be won by simply rushing about at tremendous speed, but I think any sensible man would prefer slowing down to slackening his fire.
In the days when sea fighting was the frequent occupation of the naval officer, ships were designed for fighting purposes and everything else gave way to the guns, for experience had taught the lesson that they were what won the battles; too frequently in the recent past a ship's armament has been considered rather in the light of an accessory, to be determined at the convenience of the designer after other requirements have been met. But the experience of the past should be our present guide, and if interpreted with common sense, will lead us to sound and reliable conclusions. The test of war is not necessary to decide the relative value of different designs of modern war-ships. If we refuse to be led blindly by authority and rely upon the dictates of common sense in determining the general features of our designs, we cannot go far astray.
The criterion by which every war-ship can be rightly judged is the answer to the question, " To what specific use will this ship be put in war time, and is she well adapted to that use? "
The apparent economy resulting from building vessels essentially adapted to the peace duties of a navy is out of all proportion to the depreciation in value of such material in time of war, for which a navy essentially exists, and true ultimate economy consists in building for war purposes only.
Now while there are certain subordinate purposes for which ships of war are needed, I conceive that their principal and fundamental object is to fight other ships of war. Moreover, any given class of ships will naturally be employed in the same general way in our own and in a hostile navy.
Consequently, for whatever specific end a ship is built, it is essential that she shall be so armed as to be able to meet on equal terms a similar ship of equal size. In other words, a certain percentage of the displacement of every ship, the amount depending on her type, should be allotted to her battery, and the character of that battery should be such as to be most effective against an opposing vessel of the same type.
When, for example, we consider the uses to which unarmored cruisers would be put in war time, we find that they can be summed up under four heads: 1. To destroy the enemy's commerce and supply-ships; 2. to convoy and protect our own commerce and supply-ships; 3. to act as adjuncts to the battle-ships, keeping touch with the enemy, giving information as to his movements, and engaging his lighter vessels as opportunity offers; 4. to assist in blockading the enemy's ports.
But in each of these employments they must come in contact with similar ships of the enemy's fleet; if we employ cruisers to attack the enemy's merchant marine, he will employ cruisers to convoy and protect them, and vice versa. If he can afford to convoy with battle-ships or to obstruct a trade route with armored cruisers, we must likewise attack and defend commerce with armored ships. On the whole, I do not see how a better rule can be laid down than that every war-ship should be designed for the specific purpose of meeting and whipping any hostile ship of the same class and size.
Of course, a logical deduction from this rule is that the type of ship should be determined by her displacement. Every ship above a certain size should be partially armored, and every ship of a still larger size should be a battle-ship, and this conclusion I personally accept as correct, although it is contrary to universal practice.
Exclusive of torpedo vessels, I would have only three classes of war-ships—unarmored cruisers of moderate displacement, battle-ships of the greatest displacement allowable, and armored cruisers between the other two. Then, as it used to be in the old days, the fighting force would be proportional to the displacement, and none of our ships would have to ignominiously flee from an enemy of equal size. If we build ships to fight, it would certainly seem reasonable to require their cost to be a measure of their fighting value; and I believe that war vessels should be bunt for this purpose primarily, not for running after mail steamers or running away from an enemy. Let us then, in the light of the foregoing rule, consider what composition and arrangement of battery is best suited to the various types of ship.
But to do this we must first formulate a method of measuring the relative efficiencies of batteries. What are the factors whose product is a true measure of the value of a given arrangement of guns on any ship when used against an opposing vessel of given characteristics? The value of any one gun is proportional to, 1st, its projectile weight; 2nd, its rate of fire; 3rd, its arc of train; 4th, the area of the opposing ship against which it is effective; and 5th, the importance of the parts of the opposing ship against which it is effective, and their position. In reality, the "weight of projectile" should enter into the formula to a slightly higher power than unity, and in not so using it we are underestimating the value of caliber. This, because the chances of hitting with the big shell are greater than with the small one. The accuracy of modern guns is practically the same for all calibers, and so is the muzzle velocity, but the large projectile loses velocity more slowly, and consequently has a flatter trajectory than the small one. However, to say that the value of a gun is proportional to the weight of its projectile, other things being equal, is near enough to the truth for all practical purposes.
In making the value of a gun proportional to its arc of train, again we are not strictly correct. In the very nature of things an enemy will be more often on one side than ahead or astern, and consequently a gun training over the 900 from bow to quarter is much more valuable than the same gun so placed as to only cover the 90° from one bow to the other or from one quarter to the other. It happens, however, that the form of a ship's deck makes it necessary, if a number of guns are carried, to mount most of them in broadside. The only practicable head fire must come from such guns as can be mounted at the extreme forward end of the battery, and the only practicable stern fire must come from guns similarly situated at the after end.
The fact that a ship is eight or ten times as long as she is broad, and that you cannot without great sacrifices have more than two tiers of guns, makes it inevitable that broadside fire should predominate. Consequently, while in assuming all arcs of train of equal extent to be of equal value we commit an error, this is compensated for by the fact that the guns with the least valuable arcs of train, ahead and astern, are few in number and are therefore of increased value, because if removed they would leave the ship with no offensive power in those directions. In other words, although heavy head or stern fire is less important than heavy broadside fire, still some head and stern fire is very desirable.
As to the 4th and 5th factors—area of enemy against which effective, and importance and position of that area—these are frequently not taken into account, and yet are of almost determining value. Evidently, if your gun cannot penetrate any portion of your enemy it is absolutely valueless, whereas if it be effective against the entire area of the enemy it has the maximum possible value as far as its chance of doing harm is concerned.
Again, if only effective against unimportant parts of the enemy, evidently a gun has small value as compared with one which can pierce her vital parts. Finally, the distribution of the vulnerable parts is of importance. If the area which a gun is effective against is composed of several smaller areas widely separated, that gun is of less value than if it were effective against an equal area all at the center of the enemy, because in the latter case the chance of hitting a vulnerable part is the greater. Consequently, in assigning value to a gun we must use a numerical factor depending entirely upon the character of the opposing target, and measuring not only the area against which the gun is effective, but the importance and distribution of that area.
Having thus decided as to the method of measuring the value of a single gun, the next step is to determine the value of a number of such guns arranged in a given manner. Of course, if each gun trained over exactly the same arc, both as to extent and position, then n guns would have n times the value of one gun. But suppose, to present the problem in concrete form, we have two guns so arranged that both fire over the same 180° from right ahead to right astern on one side, would this arrangement be better or worse than having one gun on each side each with 180° train? In the first case you could bring two guns to bear as long as the enemy was on one side, and would have no offensive power against an enemy on the other side. In the second case you could always bring one gun to bear on an enemy; but never two.
For my own part I should prefer the concentration of fire over a limited arc in a single ship action, and all-around fire at the expense of power in a fleet action; but it seems probable that in the long run the advantages and disadvantages of the two arrangements would about balance. Consequently I conclude that the measure of the value of any given battery may be arrived at by taking for each gun in the battery the product of its weight of projectile, rate of fire, arc of train, and a numerical factor depending on the character of the target, and adding these products together, which may be summed up by saying, the best battery is the one which gives the greatest volume of effective fire over the largest arc. And it is the qualifying word effective in this statement which clearly shows how necessary it is to know the character of her probable adversaries before we can properly assign the battery to any given ship. Measured as above, the most efficient battery for use against a battle-ship will be seen to be very inefficient against an unarmored cruiser, and vice versa.
Beginning then with the unarmored cruiser class, let us see what is the most effective battery which such a ship can carry. First, as to caliber, since the weight of the projectile is proportional to that of the gun, and since rapidity of fire increases with decrease in size, it is evident that the smaller the caliber the greater the weight of the projectiles fired in a given time by guns of a given aggregate weight. In other words, 100 tons of 6-pdr. guns will fire several times the weight of projectiles per minute that 100 tons of 5-inch guns will, which would lead us to the adoption for the batteries of unarmored ships of the smallest rapid-fire gun which is effective against similar ships at fighting ranges, were it not for the fact that neither space enough nor crew enough are available for the number of very small guns which can be carried on the weight allotted for the battery of the average unarmored ship. The 14-pdr. is about the smallest gun which can be considered as effective against an unarmored ship at 2000 yards range, and if the entire ordnance weights of the Chicago, for example, were given up to 14-pdr. guns and ammunition, she would carry about 120 of these guns, and the weight of metal thrown per minute by such a battery would greatly exceed that thrown by an equal weight of larger guns. But it would be impossible to find emplacements for so many guns or to carry the crew for their proper handling. Consequently we are forced to go to a higher caliber, and practically we find that maximum effect is given by a battery of the largest guns to which the rapid-fire principle can be applied. This I take to be the 5-inch caliber, the fixed ammunition of which, weighing 95 pounds, is about as much as one man can handle readily at sea. I would have, then, the batteries of all unarmored ships composed exclusively of 5-inch rapid-fire guns, except where the small displacement limited the number of guns too much, in which case the 4-inch gun should be used. Against an unarmored ship such a battery will give the maximum volume of effective fire.
The next question is, what is the best arrangement of such a battery, and it is evident at once that if a considerable number of guns are to be carried they must be in broadside. Of course the mounting of spar deck guns on the center line has the same advantages on unarmored as on armored ships, but it is seldom practicable to do this with small guns—only in the extreme bow and stern of the ordinary cruiser can a 5-inch gun be so mounted as to fire on both sides. If but a few guns are to be carried, they can be put in separate compartments and widely separated; but this, in my opinion, is undesirable. Not only is control of the battery rendered very difficult, but the number of casualties will be increased, owing to the multiplication of bulkheads. But above all, the arrangement of the guns in broadside on one or more decks, clear fore and aft as much as possible, is absolutely necessary in order to carry enough guns to give the great volume of fire which is so desirable.
The best possible defensive position as well as the best possible offensive position for an unarmored ship is with the enemy off the broadside, and the whole aim and object of the commanding officer of such a vessel in action should be to keep in that position. The chance of being hit is then the least, the effect of a shell entering and exploding is the least, and the maximum number of guns are brought to bear.
As an example of what may be done on a moderate displacement, let us take the Chicago and compare her present battery with one which might replace it. The Chicago is now armed with four 8-inch, eight 6-inch and two 5-inch guns, besides a secondary battery. These can be replaced without increase of weight by 30 5-inch rapid-fire guns with 50 rounds of ammunition each, or if we do away with the secondary battery we can have 70 rounds each. It would seem to many unwise to have no secondary battery guns on a ship, but with a very large number of rapid-fire guns bearing on all points I am inclined to think that a better defense against torpedo-boat attack can be obtained by the use of canister from the larger rapid-fire guns than by the shell-fire of the smaller calibers. Can any one doubt on which side the advantage would lie in an action between two Chicagos, one with her present battery, the other with 30 5-inch rapid-fire guns?
It may very properly be said that 70 rounds per gun is an inadequate supply of ammunition, but this is due to the large percentage of the Chicago's displacement used for machinery and boilers. The new weights for the Chicago are 182 tons less than the old ones, and she is to have three knots more speed. Moreover, a saving of about 40 tons more is to be effected by removing her spars and rigging. Of the total saving, 87 tons is to be used for an additional coal supply, but the remaining 135 tons would give 100 rounds more per gun if allotted to ordnance. With a battery of 30 5-inch rapid-fire guns, and with 170 rounds of ammunition per gun, the new Chicago would seem likely to be at least a fair match for any unarmored ship afloat.
In criticizing the batteries of unarmored ships it is only fair to remark that the rapid-fire gun of large caliber is a development of the past few years, and smokeless powder, which will so greatly add to the effectiveness of rapid fire, is but now coming into service use.
The possible batteries of the heavy armored ships, which constitute the real fighting force of navies, on the other hand, are much the same to-day as they were when armored ships began to be built and the turret was invented. For twenty-five years the usual and only reasonable arrangement has been two or more heavy guns in turrets and a number of smaller guns wherever places could be found for them. The progress in ship construction, ordnance and armor has done nothing more than make the ships larger, the guns heavier, and the armor thicker and more resisting. There is, however, a vast difference in efficiency between batteries of equal weight and the same general character but differently arranged. If one gun can be so placed as to do the work of two guns otherwise arranged, the gain which results is very great, for the weight saved can be used in increasing the protection of the remaining guns, while the decreased number of gun positions lessens the area of target, and consequently the chance of being hit. Now, a gun on the middle line of a ship is exactly equivalent to two guns, one on each side, provided it can fire across the deck. Again, a pair of guns in a single turret can be given the same armored protection on two-thirds the weight required if they are mounted singly. It follows almost of necessity that the heavy guns of an armored ship should be mounted in pairs in turrets on the middle line. Certain other arrangements having fictitious claims to superiority have been advocated and are embodied in many foreign ships as well as in some of our own. Let us examine these arrangements.
Assuming the main battery to consist of four turret guns of very large caliber, there are four feasible arrangements:
- Four single-gun turrets, two on each side.
- Four single-gun turrets, one on each side, one forward and one aft on middle line.
- Two double-gun turrets, one on each side.
- Two double-gun turrets, on the middle line.
The first arrangement is partially exemplified only in some old French ships, the Richelieu and Ocean. The fact that but two guns can be brought to bear in any direction utterly condemns this arrangement, which is probably the worst possible one.
Plan No. 2 is a marked example of the sacrifice of real to fictitious advantages. The plausibility of the argument in favor of this arrangement is shown by the number of ships whose design embodies it—the Marceau, Hoche, Magenta, Pelayo and others. It is often claimed that with this design three guns bear on every point, but an examination of the diagram shows this not to be the case. It is doubtful if the side guns can fire directly ahead and astern, but granting that they do, even then but two guns bear over arcs of 45° on each bow and quarter, and only three on the remaining 180.0 As compared with plan 4, this arrangement, with equal armor protection, costs 50 per cent, more in weight and gives only three-fourths the weight of fire on the broadside and equal weight ahead and astern. Moreover, it gives almost double the target area of plan 3—four turrets with their barbettes and ammunition tubes as against two of but little greater diameter—as well as a grouping specially likely to be hit. Finally this arrangement renders it impracticable to carry an efficient secondary battery. If the side guns are to be fired ahead and astern no guns can be safely mounted in the space between the end turrets, and of course none can be placed outside of this space, except on a lower deck.
Plan 3 is exemplified in the Inflexible, Colossus, Agamemnon, Andrea Doria, Italia, Aquidaban, Maine, Ting-Yuen, and numerous other ships. It is another example of the sacrifice of real advantages to fictitious ones existing only on paper. This arrangement of a turret on each side has numerous variations, the fore and aft distance between the turrets being more or less in different designs. Even in the largest ship it is impracticable to have the two turrets abreast each other, and in some ships they are widely separated, one being almost on the bow and the other on the opposite quarter. The Maine is a good example of the latter variation, and I will now try to show that in no case can this arrangement equal in efficiency that shown on plan 4, although the further apart the turrets are the better.
As will be seen, the Maine's guns have, on paper, 1800 arc of fire on one side and 570 on the other. Even accepting this as practicable, the result is that only over an arc of 57° on each side can all four guns be used, whereas in plan 4 they all bear over 90° on each side. But in reality the forward guns of the Maine cannot fire, safely, closer than 5° to ahead and 15° from astern, so that there is an actual dead angle of about 20° ahead and 20° astern. Moreover, the 57° angle shown on the plans must be greatly reduced unless we wish to destroy the superstructure on and in which the secondary battery guns are mounted. Manifestly, it should be the object in handling such a ship in action to bring all four main battery guns to bear on the enemy, but to do this the enemy must be kept within an arc of bearing of about 45° on one side or the other, whereas by simply moving the turrets inboard to the central line and concentrating the secondary battery between the turrets we at once increase to 900 on each side the arc within which all four guns bear on an opponent.
When the turrets are close together and on opposite sides of the ship, as in the Italia, the dead angles ahead and astern are increased. For example, in the Rugiero di Lauria the forward turret guns cannot fire nearer than 200 to the line of the keel forward and not so near aft, giving a dead angle of at least 45 ° ahead and 45° astern, while the arc of fire across the deck is no greater than in the design with turrets far apart. In fact, the further apart the turrets are the more nearly plan 3 approaches plan 4, and, consequently, the better it is.
The arrangement shown on plan 4 is the one adopted for our own battle-ships, the Indiana class, the Iowa, and the new battleships, and it is also embodied in the Camperdown, Trafalgar and other English battle-ships. This plan has the following overwhelming advantages:
- It allows the greatest thickness of armor for a fixed weight.
- It offers the poorest target to an enemy.
- It gives the maximum weight of fire over the maximum practicable arc of train, and also over the arc of train most likely to be used.
- It gives the best opportunity for mounting a large secondary battery.
- It affords opportunity for safe stowage of a reasonable number of boats.
- No interference of fire results from the use of any gun over its whole arc of train.
Concluding, then, that two turrets on the middle line afford the best disposition for the four heavy guns, the next question is what shall the remainder of the battery be? If it were practicable to carry another pair of the largest caliber guns in a third turret on the middle line, it would be a most powerful arrangement, but several considerations prevent this. In the first place, the 900 or 1000 tons weight required is not available; in the second place, there would be great difficulties in the matter of supports and ammunition supply, on account of the necessary internal arrangements of the ship; and, finally, there would be no space left for secondary battery guns. But another consideration would lead us to condemn this arrangement; a very large part of all modern armored ships is protected by thin armor, four to six inches in thickness, which is invulnerable to rapid-fire guns but no match for the 8-inch caliber. If we carry only rapid-fire guns and 12-inch or 13-inch guns, we cannot get that volume of effective fire which is so desirable; the only projectiles which can penetrate the vital parts of the enemy will be delivered at no greater rate than one a minute, whereas by carrying 8-inch guns we can treble the number of effective shots. Concluding, then, that the four large caliber guns should be supplemented by some of medium caliber in addition to the rapid-fire guns, we have to determine their number and disposition. The Indiana class and the Iowa carry each eight 8-inch guns in four turrets arranged as in plan 1, but the arguments already advanced condemn this arrangement, and we have to choose between four turrets as in plan 2, or only two turrets as in plan 3.
Comparing the three arrangements, it is at once apparent that at an expense in weight of four gun positions we get from the first plan the fire of four guns over 2700 and of two guns over 900; from the second plan on the same weight we get the fire of six guns over 1800 and four over 1800, while from the third plan, one-half the weight, we get the fire of four guns over 180° and two over 180°. Where displacement is limited, as it is for our battleships, the greatly increased protection possible with the last plan is of itself enough to commend it, but other reasons are even stronger. With the four turret plans no space is left for a battery of small rapid-fire guns, at least four less 5-inch rapid-fire guns can be carried, and no space is available for stowage of boats. Moreover, the multiplication of gun positions increases the difficulty of regulating fire, a necessity with the battle-ship even more than with the cruiser. The gun captain, from his sighting hood on the turret top, can form no reliable estimate of distance, nor is he likely to be able to observe the fall of his shot. Some method of measuring the range and signaling the proper sight-bar setting to each gun position is essential, and the fewer the positions the easier to maintain communications.
One further and most important objection exists both to the second plan and to the third as it is shown, and that is the impossibility of the 8-inch guns firing safely over the 13-inch turrets. Blast plates have been proposed to cover the sighting hoods of the 13-inch turrets, but experiments at the Proving Grounds appear to have shown that they would prove ineffectual. Certainly with both 8-inch and 13-inch guns trained on the bow or quarter, it would fare ill with the people in the 13-inch sighting hoods when the 8-inch guns were fired.
It was to overcome this objection that the double-storied turret was first proposed by the Board of Ordnance, but it has many other important advantages.
Let us see what the advantages of the double-turret plan are, and what objections can be made to it.
1. The saving of weight. Four 13-inch and four 8-inch guns can be carried on 246 tons less weight than four 12-inch and eight 8-inch, armor thickness being the same; or with equal batteries, four 13-inch and four 8-inch, and equal armor, 160 tons is saved. This weight, or even a small part of it, enables us to greatly increase the armor protection of the 8-inch guns.
2. Smaller target area and better disposition of target. No better target could well be offered than is afforded by the arrangement of two large and four small turrets. With the enemy a little forward or abaft the beam, a nearly continuous target is made by the turrets, and the thin ones are nicely arranged about the center of impact where the greatest number of hits will occur. With two gun positions widely separated, the maximum immunity from hits is attained.
3. Better control of fire. The double turret will be trained by one specially expert man, and better results must be given by this than where there are several turrets each with its own trainer. Moreover, there are but two main gun positions to which range and other directions must be signaled.
4. Vastly better opportunities for placing the secondary battery and for carrying boats. The clear space between the turrets gives room in the superstructure for at least fourteen 5-inch guns, and on the superstructure for as many small rapid-fire guns as desired, as well as for all necessary boats. Moreover, there is absolutely no interference of the fire of any gun by another.
5. Reduction in amount of machinery and mechanism. The training engines, roller paths, rollers, etc., of the 8-inch, the slightest injury to which would put the turret out of action, are done away with, and the training mechanism of the 8-inch guns being the same as for the 13-inch, is protected by 15 inches of armor instead of six or seven inches. Should the training gear of one of the main turrets be disabled with either design, the fighting force of the ship would be almost halved, unless by skillful maneuvering the guns of the disabled turret can be brought to bear; consequently, to do this would be the main effort of the commanding officer, and with the double turrets both 13-inch and 8-inch guns would bear at the same time.
[IMAGE: The sinuous line indicatees the intersection of the line of sight on the plane of the target-ship as the firing ship rolls through an angle of only four degrees, the speed of hte target-ship being ten knots.]
The objections urged to the double turret and their answers are as follows:
1. Concentration of weights.—This is not as great as in many foreign designs, nor even as great as in the Indiana class.
2. Difficulty in supplying ammunition.—This is not great. The 8-inch shell would be stowed in the 13-inch barbette, and, consequently, the men putting ammunition into the hoists would be on different decks and not interfere with each other. In the actual hoisting of the ammunition there is no trouble at all.
3. Impossibility of training 8-inch and 13-inch guns on different parts of the enemy.—This is an imaginary difficulty. An examination of the drawings will illustrate this. The intersection of the line of sight with the vertical plane containing the enemy's ship is a curve of rapid motion, and it needs but the recollection of actual experience in aiming guns at sea to convince any one of the absolute impracticability of selecting one portion of a ship as the target. "Aim at the middle of the target" should be the almost invariable rule. In that way the maximum number of hits will be obtained. The old experience that "the waist of the ship is a death-trap" illustrates this fact, the greatest number of hits naturally being about the point aimed at; but the theory of probabilities of fire indicates that with the errors common to gun fire at sea, even where the objects to be struck are at the ends of the ship, you will get the most hits by aiming at the middle between them.
If concentration of fire is desired, then the double turret renders it possible, all four guns being fired simultaneously by electricity, but in no other way can it be obtained.
But it would be too long to fully discuss this arrangement, and I can only say that the more I have thought of it and discussed it the more firmly I have been convinced of its advantages.
As to the question of the remaining battery of battle-ships, there seems to be no doubt but that it should be made up of rapid-fire guns, and these can only be placed in the superstructure between the main turrets. In the Kearsarge and Kentucky there are to be fourteen 5-inch rapid-fire guns in broadside, and these guns cannot fail to add greatly to the fighting force of the ships. A very large area of every ship must be unarmored, and while there may be no vital parts so unprotected as to be vulnerable to the 5-inch gun, still the wreckage of the unarmored portions must tend to the demoralization of the crew. Moreover, smokestacks, ventilators, masts and boats are targets whose destruction may be a serious injury, while the gun ports and sighting holes offer possible chances of entry into the armored structures, and the water-line at the ends, as well as the sides above the belt amidships in many ships, can be so cut away as to endanger stability notwithstanding coal and cellulose protection.
As against the virtues of such a battery let us consider those of the new battle-ships which follow the Kearsarge and Kentucky. These ships are to have four 13-inch guns in turrets on the middle line, but in place of the 8-inch and 5-inch they are to have fourteen 6-inch rapid-fire guns, ten mounted in broadside between the 13-inch turrets and four on top of the superstructure also in broadside, and so arranged that one on each side fires right ahead and one right astern. Taking the rates of fire as one round a minute for the 8-inch, two and one-half rounds a minute for the 6-inch, and three rounds a minute for the 5-inch, it will be seen that with the Kearsarge plan the weight of fire per minute is 2050 pounds on the broadside and 500 ahead or astern, while with the later plan it is only 1750 on the broadside and 500 ahead and astern. But the main objection to the second plan is that the volume of effective fire is enormously diminished by the omission of 8-inch guns. The large area covered with thin armor is fairly safe from the 6-inch guns at fighting ranges, whereas the 8-inch projectile at any range, and at even a considerable angle of incidence, will penetrate it. If we measure the value of the two batteries by the rules heretofore laid down, it is evident that the Kearsarge's battery will prove much the more efficient.
We have finally to consider what is the best battery for the armored cruiser class, and first, what is the function of the armored cruiser. I consider her to be simply a ship big enough to be partially armored, but not big enough to carry very heavy guns or very thick armor, and as with all other classes of warship, she should be designed with a view to have at least equal chances in battle with any other ship of equal size. She is a cruiser of sufficient displacement to be armored, and consequently requiring guns capable of piercing armor. From my point of view, every ship of more than about 4500, and of less than about 9000 tons displacement, should be an armored cruiser. It is folly to build 9000-ton ships which can be knocked out by properly armed ships of half their size.
We have thus far designed but two armored cruisers, the New York and Brooklyn, the first of about 9000 tons, and the last of about 10,000 tons displacement with full bunkers. The batteries of these ships are respectively six 8-inch and twelve 4-inch guns and eight 8-inch and twelve 5-inch guns.
The New York's 8-inch guns are arranged four in two turrets on the middle line and a single gun in each waist. By simply putting the two waist guns in a turret on the middle line, which could be done without changing the arrangement of boilers or machinery, how much more powerful her battery would be! In order to use the 4-inch guns the enemy must be kept not greatly forward or abaft the beam, and in this position, with present design, five 8-inch guns would bear, while by the proposed change all six would bear. In the same way how greatly improved the Brooklyn would be by putting her side 8-inch turrets on the middle line, or if that be impracticable, which I do not believe, by giving her only three turrets, all on the middle line. These would give exactly the same fire on the beam as is now given by four turrets, and the saving of weight could be used to great advantage in increasing the thickness of the turret armor.
As for the rapid-fire guns of an armored cruiser, they should be arranged on a single deck in broadside, and should be as many in number as space will allow.
There is no lack of displacement available if we only dispense with the many worse than useless weights which we now carry. Let all useless bulkheads be removed, all wood sheathing torn off, and we can put a battery of rapid-fire guns on the New York and Brooklyn that will render it unnecessary to answer the frequent and annoying question of visitors to those ships, "But where are your guns?"
[*] Lecture delivered before the Naval War College.