Maritime War and Maritime Strategy
We must not forget at this moment how much we owe to those who have gone before us and have created the Fleet as it now is; those who worked so arduously and so long to be ready for such a moment as now been forced upon us.
Vice-Admiral Sir David Beatty's message to the 1st Battle Cruiser Squadron, 4th August 1914.
THE volumes of which this is the first set out to tell the story of the development of our maritime strategy from 1939 to 1945, and of its application to the unceasing struggle for the control of communications across the broad oceans and in the narrow coastal waters. During the three centuries or so of our history as a world power it has several times happened that a far stronger continental coalition has pitted its might against Britain and her allies, has won a series of resounding victories on land only to find itself brought up against a method of waging war with which its leaders could not grapple and of which they had no clear understanding. Yet, ultimately, our maritime strategy, founded on centuries of experience of the sea, brought our enemies to utter defeat.
When Britain and France took up the new German challenge in 1939 they took it up on the Continent. But when the enemy's land victories of 1939 and 1940 had deprived us of all our continental allies a change of emphasis in our strategy became inevitable--if for no other reason, because only two methods of continuing the war against Germany remained open to us. One was the offensive use of our initially small bomber force against German military and industrial targets; the other was to exploit to the utmost our traditional capacity to employ a maritime strategy as the means of bringing overwhelming forces to bear against the enemy in theatres of our own choice.
The experiences of the last war appear to reinforce those of earlier struggles which had shown that the prosecution of a maritime strategy passes through several phases. In the first it is probable that our strategy will be defensive, particularly if a new continental coalition has to be constructed. During this phase our maritime power is used
to defend these islands from invasion, to cut the enemy off from the rest of the world and weaken his economy by enforcing a blockade, to hold and reinforce certain key points and areas overseas and to bring to this country the supplies which are essential to its survival. But while it may be necessary to accept that our strategy must, during this phase, remain defensive it is of cardinal importance that no opportunity should be lost to assume the tactical and local offensive against such enemy forces as may present themselves. If such opportunities are lost the period of the strategic defensive may bring about a decline of morale and of the will to fight. Assuming however that war remains such as it has been hitherto, and that our commanders seize every opportunity for local and tactical offensives, the period of the strategic defensive possesses certain inherent compensations. Chief among these is that, while our war economy develops, while our resources are mustered and our military strength expands, the enemy is forced, if he wishes to attack us, to do so across seas which he does not control. Such ventures, if made, expose his forces to drastic counter-measures and may result in expensive failures. The unwillingness of the Germans to accept such risks during the recent war is underlined by the immunity from attack of such key points as Iceland and the Azores. During the second phase our maritime forces continue to carry out the functions which occupied their whole capacity during the first, but in addition the nation's offensive power is being developed. Forces of all arms are being built up, assembled and trained; and plans for their offensive employment are being prepared. This phase, which ends with the first major offensive operation, may well be entitled 'The Period of Balance' since the success or failure of the first offensive has yet to be decided. In the third phase the full advantages of the patient pursuit of a maritime strategy are reaped and our forces are transported overseas to assume the offensive.
It is the writer's intention to devote one volume to each of the three phases, thus defined, through which our maritime strategy passed. But before that narrative is opened it may be useful to consider in further detail certain aspects of maritime strategy in its modern form and also the method whereby a maritime war is fought.
Maritime strategy has been defined as 'the principles which govern a war in which the sea is a substantial factor'--a definition which plainly applies to the whole course of the recent struggle.1 But whereas in the many previous wars successfully conducted by Britain on the basis of a maritime strategy the forces employed to that end were mainly ships, in the recent war aircraft came to exercise a profound and increasing influence on the success or failure of the strategy.
It is therefore essential to place in proper perspective from the outset of our story the extent to which this new instrument of war conditioned and controlled the execution of our maritime strategy. Precisely how great that influence would be was, in 1939, largely conjectural, but it did not take many weeks of war to demonstrate that it was very great indeed. It is undeniable both that some naval thought had rated the influence too low and that a body of opinion on the air side had rated it too high. Some account of the pre-war investigations into this matter will be given later; the essential point to stress here is that, wherever in these volumes reference is made to the control of sea communications, the reader must assume this to mean the exercise of such control by forces of no matter what arm or service as will enable our trade convoys, our troopships, our cargo vessels and tankers, our coasters and fishing vessels and, indeed, all forms of traffic upon the surface of the sea, to pass on its way unhindered. It is therefore axiomatic to the entire consideration of our subject that control of sea communications in the modern sense necessitates a large measure of control of the air over those communications as well as control of the waters beneath the keels of the passing convoys. If either control of the air over the sea or control of the water beneath the surface of the sea is inadequate, then we should not possess sufficient control of the communications which pass on its surface.
The aim of maritime strategy is therefore not so much to establish complete control of all sea communications, which would be an ideal hardly attainable until final victory was almost won, as to develop the ability to establish zones of maritime control wherever and when, ever they may be necessary for the prosecution of the war in accordance with the directions of the Government. And a zone of maritime control means no more than an ability to pass ships safely across an area of water which may be quite small in extent or may cover many thousands of square miles of ocean. Thus the enemy, mainly by the use of aircraft, established for some time a zone of maritime control in the central Mediterranean which, while it lasted, virtually denied to us the use of the communications through that sea. And the crisis of the whole struggle in the west developed, after the Battle of Britain had been won, from our need to establish a zone of maritime control over the entire length of the Atlantic shipping lanes and the enemy's sustained attempts to defeat that control. It must, however, be emphasised that complete control of even a restricted zone is rarely established, and that it is far more common for control to be in dispute than undisputed. Moreover, if control over a particular zone is lost by one belligerent it is by no means certain that it will pass to the other. In this stage it is more likely that control will remain in dispute and such, for example, was
the condition in the English Channel in the summer of 1940. Furthermore, throughout the period when control of sea communications is in dispute, and even after the establishment of a reasonably firm zone of maritime control, sporadic attacks will remain a possibility. Such attacks on our sea communications persisted almost to the end of the recent war.
Wherever, therefore, a zone of maritime control is established, our own commercial and military seaborne traffic will be able to pass in reasonable safety. But there is a further effect of the establishment of such a zone. It will automatically bring about the denial to the enemy of the use of the same sea communications. In other words, the creation of such a zone produces a positive result to ourselves and a negative result to the enemy; and the latter can be as important as the former. Thus by creating a zone of maritime control in the focal area for shipping off the River Plate we protected our own South American trade and prevented the enemy from using the same routes; and when the zone of maritime control essential for the North African landings of 1942-43 had been completely established, we denied the enemy the use of sea communications adequately to succour and support his own armies in that continent.
The denial to the enemy of the use of sea communications is accomplished by the application of all the various instruments comprising maritime power, but the sum total of their effects can be described as being the establishment of a blockade. This is one of the chief means whereby a nation which is stronger at sea may be able to impose its will on one which, though stronger on land, is not self-supporting in food and raw materials. In spite of German arguments to the contrary, which read strangely from a nation well versed in the exaction of all sorts of rights, penalties and requisitions from nations subjugated by continental campaigns, it is a relatively humane form of war. In common, however, with other aspects of the exercise of maritime power it is slow and cumulative in its effects; on the other hand, it starts to function from the day on which hostilities open.
If we turn now to the means whereby a maritime strategy can be implemented, it is necessary to emphasise that, although modern developments have greatly changed the instruments of war and the various duties performed by each of them, the old-established principles governing their use do not seem to require modification. Maritime power is still 'the expression in material of the strategical and tactical ideas that prevail at any time'; but the material has changed out of all recognition, and within a space of about half a century.2 From the days when British sea power first began to make
itself felt throughout the length and breadth of the globe right down to comparatively recent times it was accepted that the fleet which controlled the sea routes and fought off all challengers must comprise three classes of warship. They were called the ships of the line or battleships, the cruisers and the flotilla vessels. The cruisers actually exercised control of our sea communications--supported by the battle fleets to prevent interference with our cruisers by more powerful enemy units--and the flotilla vessels acted as scouts for the battle fleet and carried out multifarious functions as escorts and in local defence.
There were, prior to the outbreak of war in 1939, plain indications that the old conception of the means whereby maritime power was wielded and a maritime strategy implemented was no longer valid. But the extent of the changes was, perhaps, not fully realised until some months after the outbreak of war. It seems, therefore, justifiable to attempt a redefinition of the elements comprising maritime power, and the chief reason why this has become necessary is that shore-based and carrier-borne aircraft have shown themselves to be capable of carrying out a part, and in some circumstances the whole, of the duties borne for so long by one or other class of fighting ship. In the recent war they acted repeatedly in the traditional function of the battle fleet to seek and destroy the enemy's principal naval units. The attack by naval aircraft on the Italian battleships in Taranto harbour in November 1940 was the first example of their successful use in this manner, and it is probable that this brilliantly conceived and executed operation influenced Japanese thought, and was a factor in the decision to employ similar methods against the American fleet in Pearl Harbour in December 1941. The United States Navy, when its turn came, also repeatedly demonstrated the capacity of carrier-borne aircraft to perform this function, and in the final phase of the Pacific war the two greatest Japanese battleships succumbed to the sustained attacks of naval aircraft alone. The heavy shore-based bombers of the Royal Air Force, after an inauspicious start, became an increasingly important factor in operations planned to the same purpose, and it was they who finally sank the German battleship Tirpitz after she had been disabled by various other forms of attack. So much for the capacity of shore-based and carrier-borne aircraft to execute a part of the traditional function of the battle fleet. In fleet reconnaissance work and shadowing an enemy, which were formerly the functions of ships classified as cruisers, the influence of aircraft became, as the recent struggle progressed, scarcely less profound. From small and uncertain beginnings and many failures in the difficult weather conditions of the North Sea, the reconnaissance aircraft of the Navy and Coastal Command played an increasing part, especially when the introduction of airborne radar enabled them to
overcome the handicap of night or of low visibility.3 In anti-submarine operations and convoy escort duties the aircraft of both Services first supplemented the arduous work of the flotilla vessels and then, in the crisis of the war, became a decisive factor in the struggle to defeat the U-boat. Lastly, the fighter aircraft of both services constantly acted as an integral part of the defences of the fleet, of mercantile convoys and amphibious expeditions and of naval bases or commercial ports, thus performing a part of the function of the third traditional class of fighting ship--the flotilla vessels.
Not only, therefore, have aircraft developed the capacity to carry out a part of the functions of all three traditional classes of fighting ship, but the conditions of modern warfare, and in particular the rapidity with which the enemy can develop a large variety of attacks, have altered the traditional conception of the functional employment of the ships themselves. For example, the enemy used his battleships and heavy cruisers as commerce raiders, and this forced us to use ships of equivalent strength as ocean convoy escorts; the Americans and we ourselves used battleships to escort and cover aircraft-carrier squadrons; specially equipped cruisers were used for anti- aircraft protection of convoys; and small aircraft carriers worked as flotilla vessels in anti-submarine operations and in the protection of shipping.
Only in the use of flotilla vessels does it seem that the older functions still hold good to any appreciable extent, and that, perhaps, because their duties were always the most varied. In fact it is plain that the traditional conception of the classification of fighting ships and their roles in the exercise of maritime power requires radical reconsideration. The old names remain, but the functions have changed out of all recognition. Perhaps the truth of this argu- ment is best demonstrated by the manner in which all the maritime powers involved in the late war used mixed forces comprising most, if not all, classes of ship and aircraft to carry out particular operations. The Americans called these Task Forces.
Study of recent trends and developments leads therefore to the suggestion that maritime power to-day rests on the possession of three essential elements. The first comprises all the varied instruments of war which work on or beneath the surface of the sea or in the air above it. It can be called the Strength Element, for it is on their strength and numbers that maritime control greatly depends. Second comes the possession and safety of the bases from which all the instruments of maritime power must work. If bases are lacking, or are inadequately defended, the ships and aircraft cannot fulfil their
functions. This can be called the Security Element. The third element of maritime power comprises the Merchant Navy, which must be adequate to feed our home population, to bring in the raw materials needed by our industries, to carry our exports overseas and to transport our armies and their multifarious supplies to the theatres where they are required to fight. Nor is the Merchant Navy by itself enough. It must be supported by an adequate shipbuilding and ship-repairing industry to enable losses to be replaced and damaged ships to be returned rapidly to service. This can, perhaps, best be called the Transport Element. If it is inevitable that, in maritime war, the actions fought by the warships and aircraft gain most attention, it must never be forgotten that the purpose of those actions is, nearly always, the protection of the merchantmen; and without the steady devotion of the men who man those ships the whole structure of maritime power must crumble.
Such, then, appear to be the elements comprising maritime power in a modern context; and each of them must be present in adequate form if the nation's maritime strategy is to be fulfilled. But to leave the matter there is, perhaps, to oversimplify the issue and some expansion may be necessary.
Strength by itself cannot ensure success; it must be applied at the time and in the place where it is needed, in adequate and balanced form and for the whole of the required period. This plainly demands flexibility in the application of maritime power and concentration of its instruments. Concentration has been called 'the assembling of the utmost force at the right time and place', but it must not by any means be taken to necessitate the massing together of ships and aircraft.4 A true maritime concentration is a far more subtle conception. It is well expressed by Mahan's definition of warships working in close co-ordination 'not huddled together ... but distributed with a regard to a common purpose, and linked together by the effectual energy of a single will'.5 If aircraft be included with the ships of which he was speaking, this is as true to-day as when it was written. A maritime concentration must, therefore, maintain its flexibility and cohesion whilst covering as wide an area as is necessary. Many examples in which a concentration of this nature was brought about on the Admiralty's orders will appear in our narrative, and it will be seen how they were often the antithesis of the massing of warships.
In operations for the defence of merchant shipping we have always to deal with a large variety of possible enemy objectives and combinations, and this will produce a tendency to disperse our forces. The proper answer is to keep our concentrations as open as possible
whilst maintaining their fundamental cohesion. But in applying this principle to the conduct of maritime war it is well to recognise that there will always be a conflict between maintaining cohesion and the requirement for our forces to reach out as far as possible and to cover the widest possible area. The point at which the extension of operations will destroy cohesion is indeed difficult to estimate, but that it exists is beyond doubt, as several examples from the late war will show. Perhaps the clearest indication of the point beyond which flexibility cannot be stretched without loss of cohesion lies in the existence or lack of a well-placed and powerfully held strategic centre on to which our forces could fall back in case of necessity. In all our operations against powerful German raiders in the Atlantic such centres existed at Scapa Flow, at Halifax and in the Straits of Gibraltar; and the knowledge that our widely separated groups and ships could, in case of necessity, fall back on those centres for support rendered the measures ordered by the Admiralty perfectly sound examples of maritime concentration.
There are certain other aspects of maritime concentration which merit some consideration. The first is that the degree of division of our maritime forces which we must accept is directly related to the number of ports and the length of coastline held by the enemy and from which he can attack our trade. Thus the enemy's control, after the summer of 1940, of the whole Norwegian, Danish, Dutch, Belgian and French coasts, and particularly of the first and last, greatly complicated the problem of watching the ports from which our sea communications could be attacked, and imposed the necessity for greater division of our strength. The immediate despatch to Gibraltar, in June 1940, of a British force to replace the lost French maritime power in the western Mediterranean, is an example of such division, and a wholly correct division of our forces. It was, however, fortunate that our naval superiority was such as to permit such a division being made without unduly weakening the Home Fleet which, as Lord Barham (First Lord of the Admiralty during the Trafalgar campaign) remarked, îis the mainspring from which all offensive operations must proceed'. The division of our forces in this manner is dictated by the necessity to leave unwatched no port from which forays against our merchant shipping can be launched. But this requirement is modified by two factors, one of ancient establishment and the other of modern impact. The first is the extent to which the enemy's lines of operations cross our own home waters. If they do so entirely, as from the Danish, Dutch, Belgian, southern Norwegian and north-western French coasts, then the necessity to watch the ports on those coasts is much simplified. The second is that air reconnaissance has greatly eased the difficulties of simultaneously watching a large number of ports. Without this modern development
the division of forces necessitated by watching so long a coastline and so large a number of ports would have been beyond our powers; for the requirement undoubtedly is to leave no port unwatched, since failure to do so will enable the enemy to adopt sporadic action from the unwatched ports. If all his ports are watched and we are thus able to deny to him the possibility of sporadic action, he must either remain inactive or concentrate his forces. This is exactly what occurred in the case of the stationing of the German battle cruisers at Brest from March 1941 until February 1942. They were watched, chiefly by air reconnaissance, blockaded and forced into inactivity. The sporadic action for which purpose they had been stationed there was denied to the enemy, and he was finally forced to concentrate by passing them to his home ports by the easiest route.
Maritime strategy in face of a threat to invade our shores also requires some special consideration. There is a tendency, in such circumstances, for the public to demand the massing of our forces around our coasts. Such a policy, if adopted, would be a false concentration; the attitude adopted would be wholly defensive, and the initiative would rest with the enemy who might thereby be given the very opportunity he seeks. The traditional British policy, and it has been successfully applied many times in our history, is quite different. In the first place the enemy transports which are assembling to carry, or are actually carrying his army, displace his warships as the primary object of our maritime forces. A firm grip over the assembly of the transports is established by blockade. To-day this includes bombing, bombardment and minelaying as well as constant watch and patrol off his assembly ports. The blockade is enforced by flotilla vessels and aircraft, but they must be supported by greater strength and covered by the battle force in the background.6 The threat of invasion is clearly visible to the layman; the countermeasures are probably concealed from him. But they are none the less effective for their invisibility from the land, and there should be no uneasiness in British homes as long as the old methods are applied and the strength and vigour of our maritime forces remain unimpaired.
Assuming, however, that the old policy is adopted, the enemy must try either to force his invasion army through in one large mass, or to slip through whilst evading our blockading forces. The second choice can hardly be applicable to a modern expedition attempting to cross narrow seas. The first choice is extremely favourable to the defence; it produces exactly the conditions for which we have always
hoped and has, again and again in our history, led to decisive sea battles. It appears that Hitler intended to adopt this course in 1940, thereby following in the path of many earlier continental strategists, and that the British policy which frustrated and defeated the intentions of his forerunners also destroyed his plans. Indeed, study of contemporary German documents leaves little doubt that the quarrelsome vacillations of the German leaders were chiefly caused by the uneasiness which always seems to be produced among our enemies when it becomes apparent that an invasion is to be launched across seas which they do not adequately control. The lessons of 1940 appear to reinforce our knowledge that, although continental enemies have repeatedly tried to find a way to invade these islands without first defeating our maritime forces, no such short cut exists.
There remain for consideration before leaving this discussion on maritime warfare two further points of some importance. The first is the tradition of seeking decision with the enemy by battle at sea. This has long been a fundamental precept in our maritime services, and it is a tradition of immense power and value. None the less it is a precept which can be carried too far, and our history contains examples where it has only led to indecisive battles. It must, in truth, be constantly tempered by the judgment and experience of those responsible for the conduct of operations, since it is well established that, if enthusiasm for battle outruns judgment, the blow will fall upon air; whereas by waiting with forces correctly disposed we shall compel the enemy ultimately to offer an opportunity for action. It happened many times in the war that commanders of our maritime forces assumed the tactical offensive, often against superior strength, with great gallantry and most favourable results; and it now seems that our adversaries sometimes sacrificed a potential advantage through reluctance (often imposed on them by higher direction) to do likewise. None the less the well-known capacity of a defensive strategy in certain conditions to inflict grievous injury on the enemy and to stultify his purpose still holds good. Perhaps the outstanding example from the last war relates to the defeat of the enemy's attack on our merchant shipping. Though it was not at once accepted there now seems no doubt at all that it was the defensive strategy of sailing ships in convoy and of providing the convoys with powerful surface and air escorts which did most to accomplish that decisive victory. Yet it was the desire at once to assume the offensive against the U-boats which led to the persistent employment, during the first year and more of the war, of flotilla vessels to hunt enemy submarines in the vast ocean spaces instead of using them to escort our convoys. Not only did the early hunting groups achieve negligible success, but the dispersal of our slender resources in that manner led to our convoys being inadequately escorted, and so suffering heavy losses, and
to many good opportunities to destroy the submarines which attacked them being missed. Equally the view that bomber aircraft could contribute most to the defeat of the U-boat by taking the offensive against the enemy's bases and his building and repair yards rather than by escorting and protecting the convoys far out at sea, is not substantiated by post-war analysis of their achievements. It is to-day impossible to avoid the conclusion that the most effective way of defeating the U-boat was by waiting for it in the vicinity of the prey which it was seeking.
The chief difficulty in implementing this policy of waiting is the reluctance of public opinion to believe that it can be a deliberate strategical move and not an example of timidity or pusillanimity on the part of our commanders. Yet the truth is that nearly all the really effective blows struck at our enemies' maritime power have come about through a deliberate tempering of the desire to seek and destroy the enemy by judgment and experience, which had taught that the object would be more assuredly achieved by offering the enemy a bait and then waiting for him to present himself. The sinking of the Bismarck and of the Scharnhorst provide examples of this, though in the case of the latter ship it was necessary to wait many months before she came to her destruction. All the major warships of the Japanese Navy which could be made fit for sea also came, ultimately, of their own accord to meet their end.
Finally--and this point is placed last in this discussion because it is not reached until the application of our maritime strategy has begun to bear fruit and the early strategic defensive can be exchanged for the offensive--we must consider the employment of maritime power to transport our armies overseas, to place them on shore in the chosen theatres, to support and supply them as may be necessary and to shift their bases forward as their land campaigns advance. It is plain that the establishment of an adequate and effective zone of maritime control in the approaches to, and the coastal waters off the disembarkation area is an absolute prerequisite for success in this type of operation. The functions of our maritime forces in an amphibious expedition of this nature differ considerably from those of the forces employed on mercantile convoy work. In the latter case their duties end with the safe arrival of the convoy in port; but in the former case they must continue to support and assist the army after it has landed, and continue to maintain the maritime control on which success on land hinges. Their function, in fact, ceases to be purely maritime; they become a part of one vast and integrated organisation comprising all arms of all services, and all working towards the common end of defeating the enemy's land forces.
The great merits of amphibious expeditions of this nature are their mobility and secrecy. By making good use of strategic and
tactical feints and defeating the enemy's reconnaissance it is possible to achieve surprise in both spheres, as, contrary to all expectations, occurred in the case of all three major enterprises (North Africa, Sicily and Normandy) launched by us and our Allies against our European enemies during the late war.
Provided that the planning and organisation of the whole vast and complex undertaking are meticulously based on inter-service understanding and co-operation, fortunate is the nation to whom the ability to undertake such expeditions falls. Though the exercise of maritime power in defence of trade is essential to the nation's war economy, and it alone can produce the conditions from which the final decisive offensive will be launched, it is by exercising this same heritage in the despatch of great military expeditions overseas that a maritime strategy can be crowned by final victory.
Outline of the Admiralty's Organisation in 1941
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