Western militaries have a knowledge gap with major force design implications. Despite several excellent histories of individual waterborne operations in irregular warfare, there appears to be no comprehensive study of these cases. Absent holistic analysis, the frequency, scale, and impact of activities like amphibious and riverine assault in irregular wars are, to be kind, underappreciated by many Western military professionals.
Two broadly held but questionable assumptions have compounded this knowledge gap and directly feed what I believe is ineffective force design: (1) a recurring head-in-the-sand belief that the United States will never again engage in any large-scale, troop-heavy counterinsurgency operation; and (2) the nearly unquestioning acceptance of the so-called mature precision strike regime, which effectively argues that advanced missiles render any kind of large- or even mid-scale amphibious operation impossible. My case-study research for Ground Combat: Puncturing the Myths of Modern War, which includes a number of irregular waterborne operations and the conventional amphibious assault at Mariupol, Ukraine in 2022, belie these assumptions.
In this article, I use the Indochina-Vietnam case to highlight historical waterborne operations in irregular war then describe some 21st century cases from the Ground Combat Database. My central purpose is to draw attention to the continuing importance of waterborne operations in order to facilitate improved Western military force design, education, and training. My secondary purpose is to invigorate further study of this underappreciated topic.
And I have a third purpose here. Collectively, this history of waterborne operations in irregular warfare reinforces the standing assumption that amphibious, river crossing, and similar missions have been and remain a consistent feature in counterinsurgency, civil war, and other conflicts all lumped together under the irregular rubric. But on close examination, many of these individual operations look a great deal like conventional combat. Given the frequent occurrence of conventional combat within irregular war cases, all studies and forecasts of conventional war—including assessments of the highest-order fighting—should also incorporate irregular aspects.
Waterborne Operations as a Constant Feature of Irregular Warfare
Ground combat frequently involves fighting across or shooting from some kind of water feature. Waterborne operations in irregular warfare can be broken out into two broad categories: (1) assault from or across and fire support from the littorals, lakes, or rivers; and (2) coastal or inland waterway transportation. Larger-scale irregular conflicts frequently involve a routine mix of two or more of these operations.
Probably thousands of historical cases of waterborne combat fit neatly within the commonly understood bounds of irregular warfare. At least in the modern Western experience, lake combat has been infrequent. But riverine and amphibious operations have been far more frequent in irregular war than most Western professionals realize. Historical analysis of waterborne operations over a century of fighting in Southeast Asia can inform our understanding of current trends. I single out this case because the scope, scale, and intensity of often well-recorded combat allows for both battle-by-battle and longitudinal analysis of waterborne operations in irregular war. It also effectively highlights the challenges we have in distinguishing between irregular and conventional war.
Indochina-Vietnam: French Operations 1850s-1954
Arguably, the French and American wars in Southeast Asia offer the best available pre-21st-century examples of routine irregular-war waterborne operations. French colonial operations in the mid-1800s were conducted primarily from the sea and from the network of rivers connecting Saigon and other key population centers to the coast. Large-scale amphibious assaults in the mid-1800s—including one involving over 14 warships and perhaps 2,500 troops executing an opposed landing at Saigon and another expedition up the Red River to seize Hanoi—gave way to routine river patrolling, ambushes, smaller riverine amphibious landings, and coastal irregular warfare through the early 20th century.
From 1945 through 1954, with initial support from the British Royal Navy and Commonwealth infantry, a French Expeditionary Corps attempted to reassert control of its former colony. After the British seized Saigon in an unopposed amphibious landing, the French deployed a heavy riverine patrol and amphibious assault force in the Mekong River Delta and along more northern waterways. French commandos, marines, and other infantry deployed on an ad-hoc fleet of modified rice barges, old US landing craft, and river boats to conduct hundreds of small- and large-scale amphibious assaults along the Mekong and other rivers.
Yes, many of these operations were bona fide amphibious assaults, even though they have not been codified as such in the Western canon or listed in any comprehensive database of amphibious warfare. For example, during Operation Moussac in 1945, a mixed—approximately battalion-level—French commando and infantry unit seized the city of Mỹ Tho in a surprise nighttime river landing. And during a heavy Viet Minh attack to seize the northern outpost of Mao Khe, the 1st Dinassaut—a French portmanteau of division, infantry, and naval assault—poured in heavy machinegun, cannon, and boat-mounted mortar fire while landing an entire parachute infantry battalion across the beach and into combat to reinforce the defenders; Mao Khe held.
While France was defeated in 1954, the tactical efficacy and—when rivers and coasts were present—the necessity of both riverine and coastal fire support and amphibious assault operations in irregular warfare was evident.
Vietnam: American Waterborne Operations
Starting in 1956, American advisors began supporting South Vietnamese River Force operations in the Mekong Delta. Organized in five River Assault Groups, these units employed a mix of landing craft and gunboats to secure waterways and put troops ashore to secure terrain and raid enemy encampments. River assault operations were fully integrated with the joint force: In 1961 alone, the River Force and the Army conducted 27 joint waterborne-land operations. While sometimes the insurgents managed to mine or otherwise disrupt river movements, many operations were successful. For example, in July 1961 a River Force and Army unit supported by artillery executed a joint amphibious assault and destroyed a reinforced enemy infantry battalion in Kien Phong Province.
When American units deployed in force to South Vietnam they expanded riverine operations on the Mekong River, in its Delta, and in the Rung Sat swamps. Navy units integrated aerial observation and fires into their patrol, raid, and assault operations, employing rotary- and fixed-wing aircraft including OV-10A Bronco light attack aircraft. Riverine assault landings were routine. For example, in June 1967, two River Assault Division units landed two battalions of US Army infantry to destroy an insurgent unit at Ap Bac, the site of a controversial South Vietnamese military failure in 1963. This time, the insurgents were destroyed by the converging amphibious assault units and supporting fires.
Amphibious assault missions were also routinely conducted from large-deck amphibious ships. From 1965 through 1969, a joint US Navy-Marine Corps unit designated the Special Landing Force (SLF) executed over 60 amphibious assaults along the coast of the Republic of Vietnam. These ranged from small ‘from-the-sea’ heliborne operations into enemy rear areas to full-scale combined-arms landings supported by naval and aviation preparatory fires. For example, in Operation Beaver Cage in 1967, Battalion Landing Team 1/3 conducted a heliborne and beach landing, putting ashore infantry and tanks before engaging in heavy combat with an enemy battalion. Smaller SLF operations were effectively continuous. In turn, the insurgents used the rivers and coastline for their own purposes.
Together, between the 1850s and the early 1970s, the French, Americans, Vietnamese, and presumably the Japanese Imperial Army and Navy probably conducted thousands of small- to large-scale waterborne operations just in this one bounded geographical space. Many of these were mid- to large-scale amphibious assaults, sometimes at the regimental level, with opposed beach and heliborne landings. While no two wars are the same, and while water played a different role in every conflict, at least the frequency (if perhaps not quite the same scale) of waterborne operations in these conflicts was loosely representative of those in global irregular warfare cases through the end of the 20th century.
Into the Modern Era: Waterborne Assault in Irregular War in the 21st Century
There has been no change to this longstanding operational trend in the 21st century. Waterborne movement and assault operations long preceded the Vietnam conflict and have continued into the modern era. During research for my book, Ground Combat: Puncturing the Myths of Modern War, I built a database of 423 battles fought between 2003 and 2022. Twenty-one of these battles either centered on waterborne operations or included a waterborne landing in direct support of a battle or an opposed assault. At least nine of these 21, and another at Deir al-Zour, Syria (which I recorded later), fit within conflicts aligned to broad irregular warfare definitions. I have summarized these cases below. The first nine are drawn from the Ground Combat Database, while the last Syria case will be added to the database.
- 2004 at Bukavu Democratic Republic of the Congo: Rwandan military units embarked Rally for Congolese Democracy (RDC) insurgents on speedboats and motorized canoes, transported them across Lake Kivu, and put them ashore so they could link up with RDC land forces for a combined assault on the city of Bukavu.
- 2006 at Muhamalai-Kilali Sri Lanka: Naval units of the insurgent Liberation Tamil Tigers of Eelam (LTTE) conducted joint amphibious and land operations to seize terrain along the Muhamalai Defensive Line, including an opposed—and repulsed—combined-arms assault on landing craft across the Kilali Lagoon.
- 2006 Muttur Sri Lanka: Combined LTTE sea and ground units attacked a naval base at Muttur. Army defenders held on while reinforcements were ferried under fire in fiberglass boats, preventing a Tiger victory. Supported by naval gunfire, Sri Lankan special forces then landed at another beach, breaking up the remaining Tiger line of attack.
- 2007 Vakarai Sri Lanka: Sri Lankan Army and special operations units conducted a three-month-long operation to destroy a sprawling Tiger complex in and around the coastal city of Vakarai. Multi-pronged land assaults through dense bunker complexes included a river crossing and probably coastal gunfire support.
- 2008 Anjouan Comoros: In 2008 Comoran and African Union troops conducted an amphibious assault on the island of Comoros off the coast of East Africa to overthrow rebel leader Mohamed Bacar. Approximately 1,500 amphibious infantry landed from ships at the port and across the beach, engaging defending rebel troops in direct-fire combat and clearing the island.
- 2009 Chalai Sri Lanka: A reinforced brigade of Sri Lankan Army infantry supported by airstrikes, rocket, and cannon artillery fires attacked to clear a Sea Tiger base at Chalai. Army units executed an amphibious assault across the Chundikkulam Lagoon, hitting the beach and attacking into defensive infantry fires. See the more detailed case below.
- 2013-2014 Bor South Sudan: South Sudanese government and Ugandan soldiers fought an extended campaign with the Sudan People’s Liberation Movement (SPLM, or Army, SPLA) to control the city of Bor. Combatants employed tanks, rocket systems, and artillery, and at one point probably 1,000 troops conducted an unopposed river crossing.
- 2015-2016 Port Midi Yemen: A coalition of Yemeni government and international forces battled Houthi and other rebel forces for control of the strategic Port Midi. Coalition units assaulted the city, employing air and naval fires. They then pushed in reinforcing troops from the sea. Small boat raids continued along the coast into 2016.
- 2016 Butig Philippines: Islamic State militants of the Maute Group attacked and seized the town of Butig from a defending battalion. Filipino units then conducted a brigade-level counterattack with air and artillery support, crossing water gaps (and possibly landing from the sea) with light armored vehicles for the final clearing operation.
- 2017 Deir al-Zour Syria: A Syrian Arab Army brigade conducted a combined-arms crossing of the Euphrates River to attack defending Islamic State forces at Deir al-Zour. Small boat teams established a bridgehead in a night crossing followed by a mechanized amphibious movement covered by artillery and both Russian and Syrian combat aircraft.
Chalai 2009: Modern Irregular Waterborne Assault Case
Digging into some of these cases amplifies the shared experiences from the cases in Southeast Asia: when water is present, it must be controlled and crossed. Rivers, littorals, lakes, and even small lagoons provide options for tactical speed, flexibility, and flanking, in many cases allowing attacking forces to obviate defenders’ terrain advantages.
The case of Chalai is instructive. Elements of four Army divisions, including an airmobile brigade, attacked to seize the Sea Tiger base at Chalai on Sri Lanka’s northeastern coast. Advancing ground units were supported by mortars, 152mm artillery batteries, multiple-launch rocket systems, and both interdiction strikes and close-air support from K’fir and F-7 fighter-bombers. Sea Tigers were dug in behind reinforced coconut log bunkers, but they also counterattacked with small units and suicide bombers.
As Sri Lankan Army foot-mobile and mechanized infantry pushed through the perimeter bunker networks, an element of the 552nd Brigade conducted a short-range amphibious assault directly into the rear of the Tiger defenses. After establishing a support-by-fire position on the near shore of the Chundikkulam Lagoon they pushed troops across on small boats and barges. Infantry cleared mines from the beach under small arms fire to allow BMP-2 infantry fighting vehicles to join the attack, and a long pontoon bridge was established. Defending Tigers were killed or fled.
Amphibious Assault—Sometimes Common and Irregular
Taking a closer look at all these battles—including those from the Vietnam War and other historical examples—much of what is described as irregular conflict upon reflection appears pretty conventional. Battalion and brigade-level, combined-arms waterborne attacks look a great deal like conventional warfare, even if the scale and intensity of combat is less than at the battles of Iwo Jima in World War II or Incheon in the Korean War. The only factor differentiating the so-called conventional waterborne assaults at Al Faw in 2003 from the so-called irregular battles listed above is subjective opinion regarding how one characterizes the larger conflict as being a traditional war among states or irregular war against a non-state actor.
Given all these cases from traditional and irregular conflicts, it is abundantly clear that both riverine and amphibious assault capabilities remain in need. Moreover, given the rising argument that the United States should apply irregular warfare to great-power competition with China and Russia, there are good reasons to rebuild and also expand these capabilities for constant global operations.
Need for Further Study
As I argue in Ground Combat, the best way to check bad assumptions, improve forecasting, and improve force design is to put more effort into modern warfare studies. Increasing hard knowledge reduces dependence on faulty or even purposefully misleading opinions. Possibly hundreds of other amphibious assaults from seas, lakes, lagoons, and both from and across rivers have taken place in the 21st century. These operations, however, have gone either unreported or are barely visible in the public domain. Indeed, one of my key findings is that all types of land warfare since the early 2000s have been poorly recorded as historical events. There are terrific opportunities here for both the military professional analysis and historical research communities. And there is much work to be done.
Ben Connable, PhD, USMC (retired), is the executive director of the nonprofit Battle Research Group, adjunct professor at Georgetown University, and part-time principal research scientist at the Center for Naval Analyses.
The views expressed are those of the author(s) and do not reflect the official position of the Irregular Warfare Initiative, Princeton University’s Empirical Studies of Conflict Project, the Modern War Institute at West Point, or the United States Government.
Main Image: Naval History and Heritage Command; Watercolor on Paper; by Gene Klebe; 1965;
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