Over the Beach: The Enduring Utility of Amphibious Operations

© Paulalanputnam | Dreamstime.com – Submarine On Surface Photo

In a previous issue of this Journal, Brett Friedman wrote of the continued relevance of amphibious operations and the advent of a 21st century renaissance. Although Friedman gave some good anecdotes on where amphibious operations could be of use, his article left unaddressed whether, after advances in modern warfighting, amphibious operations are tactically feasible or relevant forms of military operations.[i] Certainly, history has had its share of naysayers. In the fall of 1949, General Omar Bradley forecasted to the Senate Armed Services Committee that “large-scale amphibious operations will never occur again.” A year later, United States Marines would conduct a large-scale amphibious assault against the Korean port of Inchon. Following the British 1974-75 and 1981 Defence Reviews, amphibious capability was deemed as unessential and left to wither away, only to see an about face in 1982 as British amphibious forces steamed to the Falkland Islands.[ii]

The one enduring principle of amphibious warfare during the last century seems to be the debate on its obsolescence. This article will explore the concept of amphibious operations, and the amphibious assault (a subordinate operation of amphibious warfare), and whether they are still viable forms of operation in the face of 21st century technological innovation. Despite worst-case scenario predictions, with sufficient resources, manpower and planning, amphibious operations remain a viable tool in the belt of today’s operational planners.

What is an amphibious operation? Popular depictions, such as the film Saving Private Ryan, leave the impression that landing on an opposed shore is an exercise of throwing soldiers into a meat grinder to pound out a beachhead. However, this is an example of the amphibious assault (and a particularly bloody one at that), which is just a sub-component of amphibious operations in general. They are defined by American joint doctrine as “military operation[s] launched from the sea by an amphibious force embarked in ships or craft with the primary purpose of introducing a landing force ashore to accomplish the assigned mission.” Amphibious operations consist of four types of sub-operations: raids; withdrawals; demonstrations; and assaults. The first three, due to their tendency to be smaller in scale and/or only temporal in effect, tend to invite less debate on their continuing utility and any ability to effectively conduct raids, withdrawals or demonstrations predisposes the capability to conduct assaults. U.S. doctrine also lists a fifth mission; amphibious support to other operations, but this is a catch-all category to capture the non-coercive utility of an amphibious force. The focus of this article will be on the amphibious operation in general but specifically on the amphibious assault, which is defined as “the establishment of a Landing Force on a hostile or potentially hostile shore,”[iii] and its feasibility as a valid military operation in today’s operating environment.

From a political and strategic perspective, amphibious operations and the amphibious assault in particular still offer tremendous advantages to those who maintain the capability to conduct them. Unless a state is able to secure a friendly port and assembly area to off-load its ground forces, amphibious operations serve, along with airborne operations, as the primary means to conduct forced entry operations into a hostile area – a particularly salient point for countries who anticipate conducting operations away from their borders. Additionally, amphibious capability opens up additional areas to operations, with the United States Navy recently identifying the geographic reality that the Earth’s surface is two-thirds open seas with an estimated 75% of the world’s population and 80% of capital cities along the littoral.[iv]

Politically, amphibious forces allow states to muster and deploy land power to sea without incurring the significant political costs of an actual shore deployment unless absolutely necessary. Essentially, the potential energy of amphibious land forces is deployed early and stored until required, ready to use at the appropriate time.[v] Strategically, amphibious operations are advantageous as they can occur in hostile or unknown environments. They put forces ashore in a tactical posture and they can be realized without requirement of an air or sea port.[vi] As well, the deterrent effect of the capability of amphibious operations is useful – amphibious forces represent a “force in being” in a sense that the threat of their use by simply parking the amphibious force offshore can sometimes achieve the desired political effect. B.H. Liddell Hart noted that even in 1941, with the Allies still licking their wounds after being ejected from the Continent, the threat of an amphibious landing forced the Germans to keep 27% of their strength, comprising 53 Divisions, deployed along its conquered coastlines and out of the invasion of the Soviet Union. This factor was also present 50 years later in the Persian Gulf, where the Iraqis kept 6 of 42 divisions tied to the Kuwaiti coastline to meet the threat of a potential Marine Corps landing.[vii]

If amphibious raids, demonstrations or withdrawals are to be legitimate military operations, then the capability to conduct an amphibious assault must exist. Defenders won’t fear an amphibious force afloat if they know they can repel the landing. Most of the debate on the viability of the amphibious assault tends to lie on the battlefield. Any political and strategic advantages are moot, should the threat of an amphibious assault be diminished due to technological advances favouring the defenders on the beaches. Critique on the tactical viability of the amphibious assault should focus on key factors required for a successful landing. Michael O’Hanlon, in reviewing amphibious operations in the 20th century, provides three tactical prerequisites that must be attained to ensure tactical success for an amphibious force. These are the achievement of air superiority, the selection of a suitable landing location where assaulting troops can have a marked superiority over the defenders, and the ability to reinforce the beachhead faster than the defender.[viii]

As O’Hanlon’s research suggests, if a defender can prevent the attacking force from achieving two, or even at times just one, of these prerequisites then the attack will generally be unsuccessful. Thus, we now turn to the primary question of this article – what technology allows a defending force to deny any of these three factors from an amphibious force?

A simple breakdown of the defender’s arsenal can help understand how denial could be achieved. These are:

1. The submarine threat;
2. The air threat;
3. The anti-shipping missile threat; and
4. The sea mine threat.[ix]

These threats have been present throughout 20th century warfare. To understand and assess whether amphibious operations have lost their utility, it is essential to determine if technology has created a case where it can be utilized by a defender to cause catastrophic losses on an amphibious force.

First submarines: or more specifically the proliferation of cheaper diesel submarines around the world. Submarines are seen as one of the primary threats against an amphibious force preparing to launch an assault. Boynton notes that diesel-electric submarine sales have proliferated and are exist at some level in most littoral regions around the globe.[x] Due to their quiet operations and the inherent difficulties in tracking submarines in littoral waters, they are very capable of interfering with amphibious operations as they assemble and launch their landing elements.

The Falklands offers a perfect example of this; despite losing one of their two submarines, the Argentinean Navy’s San Luis was able to evade destruction by a British force that was discharging over 200 pieces of anti-submarine ordinance. As the British rediscovered, anti-submarine warfare is difficult (especially in shallow waters) and generally requires a resource commitment by the hunters which is out of proportion to the submarines committed.[xi] Williamson Murray and Lyle Goldstein make the same conclusion in their analysis of mainland China’s growing submarine fleet, noting that a post-Cold War shift by Western navies away from anti-submarine warfare only makes eliminating the submarine threat more resource and time intensive.[xii]

The threat over the water can be just as pervasive as the threat under it. In the Falklands, where the Argentineans launched a flurry of air strikes, resulting in at least 35 hits on 16 (of a total of 33) British vessels, and ultimately in four warships being sunk. Of these 35 hits, 12 failed to detonate, meaning the British likely escaped greater losses. The Argentineans were eventually beaten away, largely through British sea-based airpower and other anti-air systems and the cumulative effects of attrition on their own aircraft and aircrew. Nevertheless, this single example represents the damage a determined enemy can cause, even with less sophisticated aircraft and ordinance.[xiii]

In the 21st century, it should be obvious that the air threat has a new dimension in terms of Unmanned Aerial Vehicles (UAVs). These remotely piloted vehicles present a two tiered threat to an amphibious force. First, they can act as sensor platforms to detect an amphibious force gathering out at sea and vector on other offensive systems. Second, they can be armed and can prosecute the threat with anti-shipping missiles. Fooling a radar system is more feasible than fooling a flurry of small unmanned reconnaissance vehicles. The proliferation of these systems represents a hybrid vector, a sensory asset, between that of aircraft and anti-ship missile, which an amphibious task force must wrestle with.[xiv]

Anti-shipping missiles, composed of air-launched and land-based variants, form a third weapon that may render amphibious operations impossible. The British loss of three ships to Exocet missiles is the obvious example, while the more recent attack of the Israeli warship Hanit led by Hezbollah guerrillas in 2006 demonstrates the proliferation of these weapon systems. To counter the missile threat, amphibious forces will be forced to either stay further out at sea or to engage active detection systems, broadcasting their intent to the enemy.[xv]

The final threat, sea mine technology, has long been considered one of the ‘black arts’ of the naval trade. Likely the most cost-effective method of inhibiting amphibious assaults, Hitler ordered an extensive mining campaign of the French coastline in anticipation of an Allied landing, stating it was “more effective to sink a whole cargo at sea than to have to fight the unloaded material and personnel on land.”[xvi]

In one detailed study of the effect of sea-mines on amphibious forces, it was noted that while the principles of modern mines are not much different than those encountered during the Second World War, technology has increased their sophistication; and the techniques required for hunting and removing them are time intensive and demand the right resources.[xvii] The consequences of not having sufficient time or resources to deal with the threat of sea-mines are apparent. The follow-on amphibious assault to Inchon, at Wonson, was delayed almost to the point of failure due to the effects of a small mined field laid by “a nation without a navy, using pre World War One weapons, [with] vessels which were utilized at the time of the birth of Christ.”[xviii] Likewise, during the Persian Gulf War, the Marine Expeditionary Brigade at sea would have taken an estimated 3,000 to 5,000 casualties, had it been forced to use the uncleared waters covering Kuwait that had already claimed two ship strikes.[xix] Mines can be successfully dealt with, but this requires time and resources. The clearance of the mines in front of Utah beach, a Division-sized objective, required 84 minesweeping vessels for 24 hours. Ball estimated that clearance of the Iraqi field in the Persian Gulf in 1991 in a similar amount of time would have required 56 vessels – twice the entire minesweeping fleet of the U.S. Navy at the time, a figure that dwarfs the seven vessels actually available.[xx]

After surveying these weapon systems, we are presented with the perfect storm to render the amphibious assault obsolete. An amphibious fleet is detected by shore based UAVs and is harassed by submarines, air and missile attacks, and mines. Such a force is liable to take enough damage to prevent it from achieving the three prerequisites of air superiority, overwhelming forces on the objective beach and a successful build-up of forces on the beachhead. This factored heavily in Michael O’Hanlon’s wargaming scenario of a supposed Chinese amphibious assault on Taiwan. Estimating at least 20% casualties in the initial attempt to move by sea to the beaches of Formosa, he concluded that the chances of China establishing a rudimentary beachhead were slim and, even if this was achieved, Taiwan could quickly overrun what little could make it past the beach.[xxi] Although O’Hanlon’s assessment of balance of powers in the Formosa Strait is debateable, especially with PLAN development over the last decade, his scenario describing the process of amphibious collapse is a worthwhile analytical tool in understanding tactical vulnerabilities.[xxii]

However, such a perfect storm should only be envisioned as a worst case scenario, and it is guilty of falling into a “romanticised” (for lack of a better term) version of what an amphibious operation actually requires or resembles. Former Marine Corps Commandant Robert Cushman Jr. once warned that it was easy to build worst case scenarios and visualize amphibious assaults solely in Iwo Jima terms. Any military scenario can be perceived as doomed if situated in an impossible situation such as sailing directly into the jaws of the enemy’s strongest defences. But the defender cannot be equally strong everywhere, and amphibious operations give the attacker the advantage of holding off on a tempting target that does not suitably allow for achievement of the three prerequisites for amphibious success and waiting for the right target that will invariably show up.[xxiii]

Getting away from predictions of a modern Gallipoli, the historical record shows amphibious operations in permissive and semi-permissive environments are still completely viable. American amphibious forces were involved in operations in Lebanon in 1958, Vietnam during the 1960s, Lebanon again in the 1980s and Somalia in the 1990s.[xxiv] Likewise, the British saw amphibious forces or ships involved the Suez in 1956, Kuwait in 1961, Brunei in 1962, Tanganyika in 1964, Aden in 1967, Nigeria in 1967, and Cyprus in 1974.[xxv]

While it is obvious that amphibious operations over permissive or semi-permissive coastlines are still a viable option, can the same case be made for amphibious assaults against a hostile shore? Below are three general principles that in this author’s view support the argument of the continued utility of the amphibious operation, even in the face of modern advances in submarines, aircraft, UAVs, missiles and mines.

First, technology’s role in warfare has generally featured a corresponding advance of both offensive and defensive weapon systems, with new technologies generally being followed by counter-technology and adjustments to tactics and techniques.[xxvi] With missile technology comes the Phalanx system. With aircraft technology comes the AEGIS system. With submarine technology comes complex systems of passive and active detection from various air and sea-based platforms. Even UAVs are beholden to this phenomenon – as their use spreads, military establishments are working on measures to defeat them, whether these be through active engagement with anti-air defence systems or through electronic warfare that can attack the frequency required to control such aircraft. Although technology has ensured that the attacker will face casualties when assaulting a hostile shore, it can also ensure that these casualties are kept manageable; the feasibility of amphibious assaults need not be attached to the idea of a bloodless victory. If anything, the Falklands are a good indication of this offence/defence dichotomy in action and a modern case of a successful amphibious operation against a hostile objective.

The second principle is that technology also provides benefits to the amphibious force in reducing the abilities of the defender’s weapon systems. What is good for the goose is also good for the gander. While silent submarines can be a plague to an assembling force, the attacker can also utilize these vehicles to track and destroy enemy boats or to insert covert reconnaissance teams to assist with beachhead selection. Aircraft, and various sensor platforms such as UAVs, can deliver precision weapons’ effects on shore from afar, isolating beach defences and degrading their ability to deal with the landing force. Cruise missiles and ship-launched surface-to-surface missiles, combined with modern naval gunfire support, can help to suppress beach defences. It only seems intuitive that technology possessed by the defender and thought to render the amphibious assault obsolete can be used by the attacker to degrade his opponent’s capability to do so.

Finally, and perhaps most significantly, technology offers the assaulting force the ability to avoid the technological advantages afforded to the defender. Following the Gulf War, the United States Marine Corps recognised that its reduced resources would not necessarily permit the execution of a traditional amphibious assault in the face of a modern foe. In creating the concept of Operational Maneuver From the Sea, it sought to allow its ships to avoid the requirement to move in close to launch the Landing Force by operating over the horizon, avoiding littoral concentrations or completely skipping hardened beaches by landing over them.[xxvii] New technologies should enable this. For example, the Landing Craft, Air Cushioned can move at speeds of 40-50 knots and, due to its ability to ride on the water, it has increased the percentage of the world’s beaches accessible to an amphibious landing from 30% to 70%.[xxviii] The benefits of opening more sea flanks that, while hostile, force the enemy to defend more ground are evident.

Furthermore, the beach need not be the primary objective. Rotary aviation (including the hybrid MV-22 Osprey with extended range) is considered a staple of the modern amphibious operation, in that it can expand the radius of action and allow operations to be launched from less vulnerable areas over the horizon with minimal warning. Rotary wing aviation can also assist in quickly securing vulnerable flanks.[xxix] While fragile, the utility of rotary aviation, due to its flexibility and the mobility it offers to modern forces on land, or from sea to land, is self-evident.

When taken together, technology confers upon an amphibious force the ability to counter the defender’s weapon systems, degrade his capabilities, and avoid his strengths and subsequently to assault his vulnerable, yet still hostile, sectors. Technological advancement and proliferation provide additional factors for an amphibious force to take into account during its planning, but do not render the entire operation a failure from the start. The offence/defence dichotomy leaves equal opportunity for an attacker to achieve air superiority, dominant forces on a beach, and a quick build-up of forces on the beachhead, as it does for a defender to counter it. Just as critically, the concept of offence/defence implies the ability to avoid/spoof defender sensors prior to the operation, so as to reduce his vulnerabilities; if space-based satellites haven’t rendered fleets obsolete, then counter-detection measures are clearly possible for the modern amphibious force.

What becomes apparent from analysing amphibious warfare capabilities is that the prevalent factor tends to be the available resources. Amphibious operations are not just about moving people from point A to B, but rather about bringing combat power from the sea onto land. With regards to resource restraints on amphibious operations, the lack of shipping is a common theme. In the Gulf War, the U.S. Marine forces afloat did not receive their full complement of amphibious ships, and the U.S. amphibious fleet is now half of its 1990 levels.[xxx] The British in the Falklands were forced to utilize defenceless commercial vessels (one of which was sunk with a large proportion of the force’s medium and heavy lift helicopters).[xxxi] O’Hanlon’s China/Taiwan scenario features at its core the insufficient shipping capacity of the PRC to move enough soldiers to be decisive against Taiwan. Sea mines will be more of a threat today due to the steady decline of mine warfare capabilities in modern fleets, as these ships tend to be the lowest priority when it comes to manning and funding.[xxxiii] Goldstein and Murray point to the fact that the primary concern for American (and other nation) anti-submarine warfare capabilities is not a technology gap, but rather, due to the diminishing availability of platforms that were around when the Soviet threat was present. Indeed, the cost of securing the sea for amphibious forces is, as noted by two historians, substantially higher than the price to actually contest it.[xxxiv]

In wrapping things up, one can say with some certainty that technology has not rendered the amphibious operation obsolete. The largest inhibiting factor for today’s amphibious forces is the resource requirement to counter, degrade or circumvent the technological capabilities of the defender. Amphibious operations are a true joint force capability, requiring investment in all facets of the system to ensure viability. The levels of resources required to guarantee success are hard to determine as they are dependent on the capabilities of the defender as well as the time the attacker is willing to take, at the risk of the loss of speed and surprise, to deal with and neutralize the defender prior to hitting the beach. Going back to Friedman’s article discussed at the beginning, an amphibious renaissance is certainly possible, but only for a nation willing to dedicate itself to putting all the pieces in place. Amphibious operations onto undefended shores remain as useful a tool as they have always been, while amphibious assaults against hostile objectives remain as risky as they have always been. But if properly resourced, timed and coordinated, they can achieve a decisive effect of force projection, out of proportion to the size of the force over the beach.