The author, a renowned British maritime strategist, introduces his views on some fundamental differences between war on land and sea.
From Some Principles of Maritime Strategy, by Julian S. Corbett, pp. 139-145: "Part 111: Conduct of Naval War, Chapter 1, Introductory." Published by Longmans, Green and Company, London, England, 1918.
INHERENT DIFFERENCES IN THE
CONDITIONS OF WAR ON LAND
AND ON SEA
Julian S. Corbett
Before attempting to apply the foregoing general principles in a definite manner to the conduct of naval war, it is necessary to clear the ground of certain obstacles to right judgment. The gradual elucidation of the theory of war, it must be remembered, has been almost entirely the work of soldiers, but so admirable is the work they have done, and so philosophical the method they have adopted, that a very natural tendency has arisen to assume that their broad-based conclusions are of universal application. That the leading lines which they have charted are in a certain sense those which must govern all strategy no one will deny. They are the real pioneers, and their methods must be in the main our methods, but what we have to remember is that the country we have to travel is radically different from that in which they acquired their skill.
A moment's consideration will reveal how far reaching the differences are. Let us ask ourselves what are the main ideas around which all the military lore turns. It may be taken broadly that the general principles are three in number. Firstly, there is the idea of concentration of force, that is, the idea of overthrowing the enemy's main strength by bringing to bear upon it the utmost accumulation of weight and energy within your means; secondly, there is the idea that strategy is mainly a question of definite lines of communication; and thirdly, there is the idea of concentration of effort, which means keeping a single eye on the force you wish to overthrow without regard to ulterior objects. Now if we examine the conditions which give these principles so firm a footing on land, we shall find that in all three cases they differ at sea, and differ materially.
Take the first, which, in spite of all the deductions we have to make from it in the case of limited wars, is the dominating one. The pithy maxim which expresses its essence is that our primary objective is the enemy's main force. In current naval literature the maxim is applied to the sea in some such form as this: "The primary object of our battle-fleet is to seek out and destroy that of the enemy." On the surface nothing could look sounder, but what are the conditions which underlie the one and the other?
The practical value of the military maxim is based upon the fact that in land warfare it is always theoretically possible to strike at your enemy's army, that is, if you have the strength and spirit to overcome the obstacles and face the risks. But at sea this is not so. In naval warfare we have a far-reaching fact which is entirely unknown on land. It is simply this—that it is possible for your enemy to remove his fleet from the board altogether. He may withdraw it into a defended port, where it is absolutely out of your reach without the assistance of an army. No amount of naval force, and no amount of offensive spirit, can avail you. The result is that in naval warfare an embarrassing dilemma tends to assert itself. If you are in a superiority that justifies a vigorous offensive and prompts you to seek out your enemy with a view to a decision, the chances are you will find him in a position where you cannot touch him. Your offence is arrested, and you find yourself in what, at least theoretically, is the weakest general position known to war.
This was one of our earliest discoveries in strategy. It followed indeed immediately and inevitably upon our discovery that the most drastic way of making war was to concentrate every effort on the enemy's armed forces. In dealing with the theory of war in general a caveat has already been entered against the too common assumption that this method was an invention of Napoleon's or Frederick's, or that it was a foreign importation at all. In the view at least of our own military historians the idea was born in our Civil Wars with Cromwell and the New Model Army. It was the conspicuous feature that distinguished our Civil War from all previous wars of modern times. So astonishing was its success—as foreign observers remarked—that it was naturally applied by our soldier-admirals at sea so soon as war broke out with the Dutch. Whatever may be the claims of the Cromwellian soldiers to have invented for land warfare what is regarded abroad as the chief characteristic of the Napoleonic method, it is beyond doubt that they deserve the credit of it at sea. All three Dutch wars had a commercial object, and yet after the first campaign the general idea never was to make the enemy's commerce a primary objective. That place was occupied throughout by their battle-fleets, and under Monk and Rupert at least those objectives were pursued with a singleness of purpose and a persistent vehemence that was entirely Napoleonic.
But in the later stages of the struggle, when we began to gain a preponderance, it was found that the method ceased to work. The attempt to seek the enemy with a view to a decisive action was again and again frustrated by his retiring to his own coasts, where either we could not reach him or his facilities for retreat made a decisive result impossible. He assumed, in fact, a defensive attitude with which we were powerless to deal, and in the true spirit of defence he sprang out from time to time to deal us a counterstroke as he saw his opportunity.
It was soon perceived that the only way of dealing with his attitude was to adopt some means of forcing the enemy to sea and compelling him to expose himself to the decision we sought. The most cogent means at hand was to threaten his commerce. Instead, therefore, of attempting to seek out his fleet directly, our own would sit upon the fairway of his homeward-bound trade, either on the Dogger Bank or elsewhere, thereby setting up a situation which it was hoped would cost him either his trade or his battle-fleet, or possibly both. Thus in spite of the fact that with our increasing preponderance our preoccupation with the idea of battle decision had become stronger than ever, we found ourselves forced to fall back upon subsidiary operations of an ulterior strategical character. It is a curious paradox, but it is one that seems inherent in the special feature of naval war, which permits the armed force to be removed from the board altogether.
The second distinguishing characteristic of naval warfare which relates to the communication idea is not so well marked, but it is scarcely less important. It will be recalled that this characteristic is concerned with lines of communication in so far as they tend to determine lines of operation. It is a simple question of roads and obstacles. In land warfare we can determine with some precision the limits and direction of our enemy's possible movements. We know that they must be determined mainly by roads and obstacles. But afloat neither roads nor obstacles exist. There is nothing of the kind on the face of the sea to assist us in locating him and determining his movements. True it is that in sailing days his movements were to some extent limited by prevailing winds and by the elimination of impossible courses, but with steam even these determinants have gone, and there is practically nothing to limit the freedom of his movement except the exigencies of fuel. Consequently in seeking to strike our enemy the liability to miss him is much greater at sea than on land, and the chances of being eluded by the enemy whom we are seeking to bring to battle become so serious a check upon our offensive action as to compel us to handle the maxim of "Seeking out the enemy's fleet" with caution.
The difficulty obtruded itself from the moment the idea was born. It may be traced back—so far at least as modern warfare is concerned—to Sir Francis Drake's famous appreciation in the year of the Armada. This memorable despatch was written when an acute difference of opinion had arisen as to whether it were better to hold our fleet back in home waters or to send it forward to the coast of Spain. The enemy's objective was very uncertain. We could not tell whether the blow was to fall in the Channel or Ireland or Scotland, and the situation was complicated by a Spanish army of invasion ready to cross from the Flemish coast, and the possibility of combined action by the Guises from France. Drake was for solving the problem by taking station off the Armada's port of departure, and fully aware of the risk such a move entailed, he fortified his purely strategical reasons with moral considerations of the highest moment. But the Government was unconvinced, not as is usually assumed out of sheer pusillanimity and lack of strategical insight, but because the chances of Drake's missing contact were too great if the Armada should sail before our own fleet could get into position.
Our third elementary principle is the idea of concentration of effort, and the third characteristic of naval warfare which clashes with it is that over and above the duty of winning battles, fleets are charged with the duty of protecting commerce. In land warfare, at least since laying waste an undefended part of your enemy's country ceased to be a recognised strategical operation, there is no corresponding deflection of purely military operations. It is idle for purists to tell us that the deflection of commerce protection should not be permitted to turn us from our main purpose. We have to do with the hard facts of war, and experience tells us that for economic reasons alone, apart from the pressure of public opinion, no one has ever found it possible to ignore the deflection entirely. So vital indeed is financial vigour in war, that more often than not the maintenance of the flow of trade has been felt as a paramount consideration. Even in the best days of our Dutch wars, when the whole plan was based on ignoring the enemy's commerce as an objective, we found ourselves at times forced to protect our own trade with seriously disturbing results.
Nor is it more profitable to declare that the only sound way to protect your commerce is to destroy the enemy's fleet. As an enunciation of a principle it is a truism—no one would dispute it. As a canon of practical strategy, it is untrue; for here our first deflection again asserts itself. What are you to do if the enemy refuses to permit you to destroy his fleets? You cannot leave your trade exposed to squadronal or cruiser raids while you await your opportunity, and the more you concentrate your force and efforts to secure the desired decision, the more you will expose your trade to sporadic attack. The result is that you are not always free to adopt the plan which is best calculated to bring your enemy to a decision. You may find yourself compelled to occupy, not the best positions, but those which will give a fair chance of getting contact in favourable conditions, and at the same time afford reasonable cover for your trade. Hence the maxim that the enemy's coast should be our frontier. It is not a purely military maxim like that for seeking out the enemy's fleet, though the two are often used as though they were interchangeable. Our usual positions on the enemy's coast were dictated quite as much by the exigencies of commerce protection as by primary strategical reasons. To maintain a rigorous watch close off the enemy's ports was never the likeliest way to bring him to decisive action—we have Nelson's well-known declaration on the point—but it was the best way, and often the only way, to keep the sea clear for the passage of our own trade and for the operations of our cruisers against that of the enemy.
For the present these all-important points need not be elaborated further. As we proceed to deal with the methods of naval warfare they will gather force and lucidity. Enough has been said to mark the shoals and warn us that, admirably constructed as is the craft which the military strategists have provided for our use, we must be careful with our navigation.