Malicious Intent: Water Cannon Warfare in the South China Sea

Water cannons--once the tool of authoritarians in Nazi Germany and America's Jim Crow south--have now become the destabilizing weapon of choice for the China Coast Guard.
Kevin Edes | DECEMBER 27, 2023
Malicious Intent: Water Cannon Warfare in the South China Sea

Kevin Edes

Maritime Security Analyst



Imagine an interaction with your neighbors: they step onto your property and blast you in the face with a hose. Not just once, but every time you meet them. You ask them to stop--after all it is your property--but they just stare and spray away. Without productive dialogue or peaceful interactions, there becomes no other way to interpret this hostile act of disrespect. 

This is the reality in the West Philippine Sea. China is working with more than a garden hose.

The "Wolf in a White Hull" China Coast Guard (CCG) has been repeatedly blasting its maritime neighbor with water cannons, its now-preferred gray zone intimidation tactic. This has happened during nearly every interaction with the Philippines of late. Of late it has included when the Philippine Coast Guard attempted a routine resupply of a grounded vessel at Second Thomas Shoal and against civilian Bureau of Fisheries and Aquatic Resources (BFAR) vessels attempting to resupply Filipino fisherman at Scarborough Shoal

To review the legal status of these features within the Philippines' internationally recognized exclusive economic zone: Second Thomas Shoal is not "territory" to be claimed but a submerged reef. Scarborough Shoal is a traditional fishing ground over which China has enforced illegal restrictions, as confirmed by the 2016 Permanent Court of Arbitration ruling (para 814):

Based on the considerations outlined above, the Tribunal finds that China has, through the operation of its official vessels at Scarborough Shoal from May 2012 onwards, unlawfully prevented Filipino fishermen from engaging in traditional fishing at Scarborough Shoal.

My water cannon is bigger than yours

10dec water cannon.webp

Photo: AP

Why coast guards use water cannons.

Coast guards around the world sometimes employ non-lethal force against transnational criminal organizations to stop piracy, drugs, human, and weapon smuggling. 

No other coast guard in the world except China's uses water cannons against other country's public vessels. 

Water cannons are mounted on the side of a ship and shoot high pressure water to the amount of 20 liters of water per second, with the intent to intimidate, distract, and disorient an opposing vessel. At high pressure, the water will cause immediate damage to external ship equipment or devastating and debilitating injury to personnel caught in the direct line of attack.

For context, 20 liters per minute is equivalent to 220 pounds per square inch (psi) or 15 bar. A ship’s fire main--an artery network carrying sea water to fight fires--is between 150-175 psi (11 bar). This is equivalent to your average fire-fighting hose stream. A shower is around 40 psi (4 bar). 

At 220 psi, a shipborne water cannon can easily knock personnel off their feet and send them crashing into steel bulkheads or overboard into the sea. 

According to the ACLU, water cannons were first used as a tactic for crowd control in 1930’s Germany and expanded in the 1960’s against the civil rights movement in America.


Who are the bystanders now? Birmingham, Alabama - 1963

In a defensive maritime posture, water cannons have been primarily used by large commercial vessels against pirates. The water stream is intended to swamp open-hulled pirate vessels and prevent pirates from boarding the ships. 

The U.S. Coast Guard does not include water cannons in its non-lethal use of force arsenal. Water cannons are high powered and not accurate, elevating the risk of indiscriminate injury. 

The bottom line is that anyone--including the CCG--operating water cannons against other ships has accepted the potential for inflicting casualties.

Yes, of course it would be far worse if the CCG used bullets or other lethal force, and might well invoke the "armed attack" language from the 1951 U.S.-Philippine Mutual Defense Treaty. This is why the CCG employs water cannons in its gray zone arsenal. Nations do not want to risk escalation over non-lethal force, which has provided the CCG space to maneuver. 

However, authoritarians have historically used water cannons to dehumanize their opposition. It was dehumanizing in 1930’s Germany, it was dehumanizing in 1960’s Alabama, and it is dehumanizing today in the West Philippine Sea.

Beijing has normalized coast guard tactics that should be deemed outrageous.

The world has witnessed the CCG’s gray zone activities thanks to the Philippines' “assertive transparency” campaign, but the CCG has thus far only escalated. It has continued to use aggressive maritime tactics such as rammingblockading, and illegal occupation of maritime features by swarming CCG, maritime militia and fishing vessels. 

So let's return to our neighborhood analogy.

When your belligerent neighbor repeatedly blasts you with water in order to intimidate and control you, what are your options?

Do you stand there indefinitely and take it?

Do you call a friend to stand beside you?

Do you fight back with something larger?

What happens if someone is killed in a confrontation?

How bad does it have to get before the neighborhood bystanders step in?

These are complicated questions because potential solutions are difficult and carry risk. Everyone wants to avoid war because that is the condition where everyone loses, but this reluctance is exactly why the CCG uses this tactic. 

Beijing is escalating as far up the spectrum of conflict as the world seems to be willing to tolerate, and so far has not paid much of a price.

The Philippines deserves a lot of credit for taking the aggression on the chin and not escalating towards armed conflict. At some point, the Philippines’ friends and neighbors have to back them up, and China needs to pay more direct costs for its misuse of water cannons and other aggressive tactics. 

The foundation of international maritime law depends on it.

Kevin Edes

Kevin is a Maritime Security Analyst for Project Myoushu at Stanford University’s Gordian Knot Center for National Security Innovation. He is a Commander in the U.S. Coast Guard with advanced degrees from the School of Global Policy and Strategy at U.C. San Diego and the U.S. Naval War College. Opinions expressed are his own and do not reflect the official position of any of the above institutions.

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