Lessons of the war with Spain and other articles

by A. T. Mahan

The military function of a navy is to control the sea, so far as the sea contributes to the maintenance of the war. The sea is the theatre of naval war; it is the field in which the naval campaign is waged; and, like other fields of military operations, it does not resemble a blank sheet of paper, every point of which is equally important with every other point. Like the land, the sea, as a military field, has its important centres, and it is not controlled by spreading your force, whatever its composition, evenly over an entire field of operations, like butter over bread, but by occupying the centres with aggregated forces—fleets or armies—ready to act in masses, in various directions from the centres. This commonplace of warfare is its first principle. It is called concentration, because the forces are not spread out, but drawn together at the centres which for the moment are most important.

Concentrated forces, therefore, are those upon which warfare depends for efficient control, and for efficient energy in the operations of war. They have two chief essential characteristics: force, which is gained by concentration of numbers; and mobility, which is the ability to carry the force rapidly, as well as effectively, from the centre to any point of the outlying field where action, offensive or defensive, becomes necessary. It is essential to keep in mind both these factors, and to study them in their true mutual relations of priority, in order and in importance,—force first, mobility second; for the force does not exist for the mobility, but the mobility for the force, which it subserves. Force without mobility is useful; even though limited, as in coast fortifications; mobility without force is almost useless for the greater purposes of war. Consequently, when it is found, as is frequently the case, that one must yield somewhat, in order to the full development of the other, it is extreme mobility, extreme speed, which must give way to greater force.

This caution may seem superfluous, but it is not so; for in the popular fancy, and in the appreciation of the technical expert, and to some extent also in the official mind as well,—owing to that peculiar fad of the day which lays all stress on machinery,—mobility, speed, is considered the most important characteristic in every kind of ship of war. Let the reader ask himself what is the most pronounced impression left upon his mind by newspaper accounts of a new ship. Is it not that she is expected to make so many knots? Compared with that, what does the average man know of the fighting she can do, when she has reached the end of that preposterously misleading performance called her trial trip? The error is of the nature of a half-truth, the most dangerous of errors; for it is true that, as compared with land forces, the great characteristic of navies is mobility; but it is not true that, between different classes of naval vessels, the swiftest are the most efficient for control of the sea. Force is for that the determining element.

Keeping these relations of force and mobility constantly in mind, there is a further consideration, easily evident, but which needs to be distinctly stated and remembered. When a ship is once built, she cannot be divided. If you have on land concentrated ten thousand men, you can detach any fraction of them you wish for a particular purpose; you can send one man or ten, or a company, or a regiment. You can, in short, make of them any fresh combination you choose. With ships, the least you can send is one ship, and the smallest you have may be more than you wish to spare. From this (as well as for other reasons) arises a necessity for ships of different classes and sizes, which must be determined beforehand. The determination must be reached not merely by a priori reasoning, as though the problem were wholly new; but regard must be had to the experience of the past,—to the teaching of history. History is experience, and as such underlies progress, just as the cognate idea, experiment, underlies scientific advance.

Both history and reasoning, of the character already outlined in these papers, concur in telling us that control of the sea is exercised by vessels individually very large for their day, concentrated into bodies called fleets, stationed at such central points as the emergency demands. Our predecessors of the past two centuries called these vessels "ships of the line of battle," from which probably derives our briefer modern name "battleship," which is appropriate only if the word "battle" be confined to fleet actions.

Among the naval entities, fleets are at once the most powerful and the least mobile; yet they are the only really determining elements in naval war. They are the most powerful, because in them are concentrated many ships, each of which is extremely strong for fighting. They are the least mobile, because many ships, which must keep together, can proceed only at the rate of the slowest among them. It is natural to ask why not build them all equally fast? The reply is, it is possible to do so within very narrow limits, but it is not possible to keep them so. Every deterioration, accident, or adverse incident, which affects one involves all, as regards speed, though not as regards fighting force. In our recent war, when an extensive operation was contemplated, the speed of one battleship reduced the calculated speed of the fleet by one knot,—one sea mile per hour. But, it may be urged, will not your slowest speed be much increased, if every vessel be originally faster? Doubtless; but speed means tonnage,—part of the ship's weight devoted to engines; and weight, if given to speed, is taken from other qualities; and if, to increase speed, you reduce fighting power, you increase something you cannot certainly hold, at the expense of something at once much more important and more constant—less liable to impairment. In the operation just cited the loss of speed was comparatively of little account; but the question of fighting force upon arrival was serious.

An escape from this dilemma is sought by the advocates of very high speed for battleships by increasing the size of the individual ship. If this increase of size is accompanied by increase of speed, but not proportionately of fighting power, the measure, in the opinion of the writer, stands self-condemned. But, granting that force gains equally with speed, there is a further objection already mentioned. The exigencies of war demand at times division, as well as concentration; and, in fact, concentration, properly understood, does not mean keeping ships necessarily within sight of one another, but so disposed that they can unite readily at will,—a consideration which space forbids me more than to state. Now, a big ship cannot be divided into two; or, more pertinently, eight ships cannot be made into ten when you want two bodies of five each. The necessity, or supposed necessity, of maintaining the Flying Squadron at Hampton Roads during the late hostilities exactly illustrates this idea. Under all the conditions, this disposition was not wholly false to concentration, rightly considered; but had the ships been fewer and bigger, it could not have been made.

The net result, therefore, of the argument, supported, as the writer believes, by the testimony of history, is: (1) that a navy which wishes to affect decisively the issues of a maritime war must be composed of heavy ships—"battleships"—possessing a maximum of fighting power, and so similar in type as to facilitate that uniformity of movement and of evolution upon which concentration, once effected, must depend for its maintenance, whether during a passage or in actual engagement; (2) that in such ships, regarded as fighting factors, which is their primary function, size is limited, as to the minimum, by the advisability of concentrating as much fighting power as possible under the hand of a single captain; but, on the other hand, size is also limited, as to its maximum, by the need of retaining ability to subdivide the whole fleet, according to particular exigencies; (3) as regards that particular form of mobility called speed, the writer regards it as distinctly secondary for the battleship; that, to say the least, the present proportions of weight assigned to fighting force should not be sacrificed to obtain increase of speed. Neither should the size of the individual ships be increased merely to obtain rates of speed higher than that already shown by some of our present battleships.

Concerning that particular function of mobility which is called coal endurance,—that is, the ability to steam a certain distance without stopping to recoal,—the convenience to military operations of such a quality is evident; but it is obvious that it cannot, with the fuels now available, be possessed beyond very narrow limits. A battleship that can steam the greatest distance that separates two fortified coaling stations of her nation, with a reasonable margin above that to meet emergencies, will evidently be able to remain for a long while with the fleet, when this is concentrated to remain under reduced steam at a particular point. The recoaling of ships is a difficulty which must be met by improving the methods of that operation, not by sacrificing the military considerations which should control the size and other qualities of the vessel.

It is the belief of the writer that ten thousand tons represent very nearly the minimum, and twelve thousand the maximum, of size for the battleship. Our present battleships fall within those limits, and, although less uniform in their qualities than might be desired, they give perfectly satisfactory indications that the requisite qualities can all be had without increase of size. When more is wanted—and we should always be striving for perfection—it should be sought in the improvement of processes, and not in the adding of ton to ton, like a man running up a bill. It is the difference between economy and extravagance. Into battleships such as these should go the greater proportion of the tonnage a nation gives to its navy. Ships so designed may reach the ground of action later than those which have more speed; but when they arrive, the enemy, if of weaker fighting power, must go, and what then has been the good of their speed? War is won by holding on, or driving off; not by successful running away.