Amphibious operations are operations launched from the sea onto the land by naval and landing forces. The threat or execution of such operations can serve a wide range of purposes, extending from a demonstration of capability for coercive intent, all the way to the opening of a new campaign by means of the conduct of expeditionary warfare from the sea.
Amphibious operations need to be approached as just one of the ways in which power can be projected from the sea against the land. Naval suasion via what long has been known as gunboat diplomacy, bombardment of the shore by guns, sea-based aviation, and missile, and maritime blockade, comprise other regions of action along the full spectrum of power projection from the sea to the land.
The persisting attractiveness of amphibious operations in particular, and of power projection from the sea in general, reposes in the fact that the importance of maritime (including major riverine) communications, civil and military, has been a constant in human history. Not only does physical geography impose an essential unity, a continuity of the potential for human passage, upon all the oceans, seas, bays, and rivers of the world, but the 70 per cent of the Earth's surface that is water, on its littorals, grants ready access to 70 per cent of the Earth's population.
Amphibious operations require the integrated, certainly the well co-ordinated, conduct of sea and land (and, today, air) warfare. To launch a military operation from the sea requires an expertise that is more than simply the sum of military and naval skills. All too often, as British Maj Gen Sir Charles Callwell observed in 1905, ‘soldiers and sailors in the past in this and other countries, knowing little of each other's duties and objects, often failed to appreciate them at times of crisis’. There are huge and persisting differences between land warfare and sea warfare, yet of necessity amphibious operations comprise warfare where the land and the sea meet. Professionally excellent generals and admirals are almost doomed by their genuine, if geographically limited, expertise, to be less than thoroughly empathetic to the operational imperatives of ‘the other culture’.
Insular powers are obliged by geography to wage war both overseas and, ultimately, from the sea, since wars against continental adversaries cannot be won at sea. Victorious wars at sea have to be ‘cashed’ strategically in effect for success on land. More to the point perhaps, in the words of Liddell Hart, ‘amphibious flexibility is the greatest strategic asset that a sea-based power possesses’. Given the strategic significance of the land-sea interface, the littoral region where land power meets sea power, it follows that the ability to dominate that region translates as the ability to project power either from the shore to the sea, or from the sea to the shore. Understandably, perhaps, even in this newly ‘joint’ era, military minds—professionally trained principally for land, sea, or air duties—are not always readily adaptable to the needs of amphibious, let alone triphibious (with air), operations. When sea forces bring land forces to combat on the enemy's littoral for amphibious operations, distinctively geographically based service cultures and doctrines are apt to make unusually challenging demands upon each other.
At least seven strategically significant purposes lend themselves to support by amphibious operations. First, the advertisement of possibility of such operations, supported by physical demonstration of capability (though short of actual use), may have coercive effect. To know, for certain, that there is an amphibiously competent foe on or just over the horizon, can concentrate the mind and encourage political co-operation. Second, the credible menace of amphibious operations can be intended not so much to persuade for co-operation, but rather militarily to deceive and distract. Modern means of land communication by road and rail certainly have tilted the playing field in favour of the (land) power with interior lines of communication, but still the lurking menace of amphibious power on or over the horizon is apt to promote uncertainty as to where the blow will fall.
Third, amphibious operations, taking advantage of the vastness of the sea that facilitates operational surprise, has been a classic way to raid. In the words of Adm Sir Philip H. Colomb, ‘ravage and destruction’, as contrasted with ‘conquest and occupation’, can be wrought by seaborne raiders. Given, frequently, the length of enemy coastline, it is not difficult to appreciate the attractiveness of the raiding option. Fourth, noted immediately above, the objective of an amphibious operation may be conquest and occupation.
Fifth, an amphibious operation itself may be designed to open a campaign. D-Day, 6 June 1944, was just such an operation. When there is a strategic stand-off between insular and continental prowess, each side has to use its environmentally based superiority to seek decisive advantage in the geography preferred by the foe. In June 1944 the western Allies translated their maritime superiority into the capacity to put ashore in Normandy a capability for land-air warfare good enough to sustain itself in continental campaigning. Alternatively, when one of two continental belligerents uniquely enjoys the ability to manoeuvre from the sea, an amphibious thrust for operational advantage may be attempted. A classic example of an endeavour to outflank an enemy's army by means of maritime manoeuvre, was Gen McClellan's amphibious expedition (March-August 1862) with the Union's Army of the Potomac to threaten Richmond from the peninsula between the York and James rivers.
Sixth, amphibious menace, or actual assault, can expedite the conduct of a continental campaign that is already underway. The classic example of an amphibious operation intended to achieve such an effect was the Anzio operation of 22 January 1944. Whether or not an amphibious operation can function as a force multiplier for a great continental campaign depends, all too obviously, upon the quality of the commander (inter alia), not to mention the enemy. Seventh, amphibious operations can extract an army from a position of more or less dire continental peril. The evacuation of the British Expeditionary Force (BEF) from Dunkirk has to be the exemplar of amphibious rescue on the grand scale under fire. Nonetheless, maritime powers have had occasion to exercise their capabilities for amphibious extraction at least as often as they have practised amphibious insertion. Gen Douglas MacArthur's amphibious ‘left-hook’ around the Korean peninsula to Inchon, thereby threatening both to recapture Seoul and, especially, to cut off the North Korean army that was locked in battle deep in South Korea, is far better known than is the no less amphibious manoeuvre that enabled Allied (UN) naval forces to extract the X Corps from the ports of Hungnam and Wonsan (5-15 December 1950).
The importance of the sea and of rivers for transportation—communications—in human history, has guaranteed their strategic importance. Because we use, rather than occupy, the sea, and because the sea—and inland waters—frequently, indeed generally, have been the only practicable geographical medium for strategic exploitation, amphibious operations have been a hardy perennial of strategic history. The technical and tactical details will vary from Julius Caesar's invasion of Britain in 55 and 54 bc, to Byzantine Emperor Nicephorus Phocas' invasion of Arab-held Crete in 960, to the 1066 invasion of England by William ‘the Conqueror’, right up to the extraordinarily amphibious dimension to WW II both in Europe and the Pacific, to Korea, to the present day.
Amphibious operations have fluctuated in political and military popularity, and in apparent technical-tactical, operational, and therefore strategic feasibility. But, to date, amphibious operations as a form of war generically have survived every assault by technology and doctrine that, for a while, has seemed to menace their military practicability. Although amphibious operations have a strategic history as old as warfare itself, it was really only in the 20th century that their conduct truly was professionalized by means of systematic study, the preparation of formal doctrine, dedicated planning and training, the acquisition of specialized equipment, and the designation of some forces to be specifically amphibious in their tactical and operational focus.
Britain approached a truly ‘strategic moment’ for amphibious operations, Gallipoli 1915, with good, if not excellent, understanding of the general character and particular needs of such operations. Unfortunately, first-rate British ideas about how to conduct amphibious operations—expressed in books and in official doctrine—found next-to-no reflection in the actual preparation of forces and acquisition of specialized equipment, not to mention the all-too-specific problems of 1915.
The fiasco of Gallipoli demonstrated nothing of particular importance about amphibious operations, other than the obvious points that they need to be well, rather than poorly, conducted, according to the general principles of war, and that the often extraordinarily stressful contexts for such operations are apt to be uniquely unforgiving of error. Some people believed that the failure of the Gallipoli campaign demonstrated that amphibious operations, specifically amphibious assault operations, had been overtaken by modern technology. Railways and the several uses of the internal combustion engine—neither of which were factors at Gallipoli—allegedly meant that a continental power could transfer forces more rapidly than could the amphibious power, to win ‘the battle of the build-up’ between continental defenders and maritime attackers. Similarly, it was believed that modern firepower rendered the beach, shallow water, and the littoral approach, impractically lethal for amphibious assault.
American and British amphibious doctrine developed between the world wars challenged this popularly negative view. Looking for a new role in a harsh post-war context, the US Marine Corps reinvented themselves in the 1920s as the specialized force uniquely prepared to seize insular bases for the prosecution of a great maritime campaign across the western Pacific. The central strategic idea found enabling doctrinal support in The Tentative Manual of Landing Operations of 1934, subsequently elevated to the status of Landing Operations Doctrine, US Navy 1937. The British, whose understanding of amphibious operations—resting upon three and a half centuries of distinctly mixed experience—tended to be better than their practice, produced The Manual of Combined Operations (1938), which was congruent in all essentials with its contemporary American counterpart.
Argument in the 1930s about the obsolescence or otherwise of amphibious operations, was simply rendered irrelevant by the events of 1940-1. Germany's defeat of France and expulsion of the BEF from continental Europe in June 1940 meant that any restoration of a western front could be effected only by a grand scale of amphibious manoeuvre. Whether one liked it or not, aside from the (post-22 June 1941) land combat in the east and the none-too-promising bomber offensive, the war against Hitler's Festung Europa had to be amphibious in basic character. There was even less scope for argument over the character of the war in the Asia-Pacific region. For reasons of geography, the war against Japan had to take the form of a maritime siege of an overextended maritime empire. Landing by landing, even extraction by extraction British and American amphibious power learnt by painful practice how to apply the doctrine that in its basics was sound enough.
There can be no doubt that D-Day in Normandy and the assaults upon Iwo Jima and Okinawa comprise the finest, most complete, historical examples of successful amphibious operations. Justly celebrated though those extraordinary cases certainly are, and deserve to be, the more important fact remains that amphibious operations—for all of the purposes suggested earlier—great but more usually small, are prospectively a permanent feature of strategic history.
The leading difficulty with amphibious operations lies not in grasping the rather obvious ‘principles’ that should guide and shape them, but rather in learning how, let alone being able, to apply them in historically unique strategic situations. Nonetheless, principles are important: eight such especially command attention.
First, it is essential that each geographically specialized fighting force should comprehend, in general terms at least, the limitations, advantages, and conditions that govern the operational characteristics of the others. For example, soldiers do not need to master tide tables, but they do need to know that tides exist, and matter. Second, there is no magic formula for successful command of an amphibious operation—it may be unified, or it may be co-ordinated but sequential—what matters is that the key principles of essential unity of command should be followed.
Third, although the furtive amphibious insertion of a small raiding party—for example by a solitary submarine—is always likely to be feasible, if not reliably so, amphibious operations on a scale suitable to effect either a major raid or the seizing and holding of substantial real estate, require as a prerequisite the securing of (possibly temporary) command of the sea and of the air. Fourth, a decisive combination of common sense and bitter historical experience (Tarawa) obliges the would-be amphibious warrior to pay the most careful attention to minute details of local hydrography, as well as to the much less reliable detail likely to be available on the weather.
The fifth principle of amphibious warfare is that except for the benign conditions that permit ‘administrative’ landings, specialist doctrine, training, and equipment are required for the successful conduct of such warfare. A particularly notable feature of the Anglo-American conduct of amphibious assault in WW II was the invention of well-armed amphibious tractors for the transport of troops from the offshore ‘line of departure’ to points inland, the development of amphibious tanks, and indeed the proliferation of dedicated amphibious shipping on all scales.
Sixth, amphibious operations frequently require tactical surprise if they are to succeed. Any amphibious insertion of forces across an enemy's littoral is most likely to translate as an initial military inferiority for the amphibious power. It follows, necessarily, that the success of amphibious operations, on any scale, almost requires that the foe should be deceived as to the points of attack, though it is not the case that amphibious operations require absolute surprise.
Seventh, where feasible, amphibious forces should land where the enemy is not present, prepared, and in strength. For example, in the Falklands campaign the British in May 1982 landed at San Carlos on the west coast of East Falkland island, rather than close to the strong Argentine garrison around Port Stanley.
Eighth and finally, amphibious operations, even when conducted on a large scale, typically can have only an enabling effect upon the course of a war. The tactical, technical, and operational difficulties that attend efforts to land on a hostile shore not infrequently are so great in anticipation that too little thought is given to post-beachhead campaigning.
Bibliography
- Bartlett, Merrill L. (ed.), Assault from the Sea: Essays on the History of Amphibious Warfare (Annapolis, Md., 1983).
- Evans, M. H. H., Amphibious Operations: The Projection of Sea Power Ashore (London, 1990).
- Liddell Hart, B. H., ‘Marines and Strategy’, Marine Corps Gazette, 64 (1980).
- Till, G., Farrell, T., and Grove, M., ‘Amphibious Operations’, Occasional, 31 (1997)
— Colin S. Gray
