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Many strategists, myself included, believe that unmanned surface vessels could be part of an approach to help the U.S. Navy maintain an edge over its competitors. Unfortunately, there is little agreement on exactly what they should do.

Part of the problem is that people mean different things when they talk about unmanned surface vessels. This designation has been used to describe a wide variety of platforms in terms of hull form, size, and function — anything from frigate-sized surface vessels that are meant to complement and sail alongside “legacy” surface combatants, to one-way kamikaze attack drones like the initial iterations of Ukraine’s Magura.

The discussion over how the U.S. Navy should employ unmanned surface vessels would benefit from drawing a distinction between munitions-like surface platforms that behave like mobile mines and ship-like unmanned surface platforms that serve as low-end fleet combatants. Delineating between the two types of vessels would help point out the pros and cons of each, which would then help strategists understand the best ways to employ them against particular threats.

Against adversaries with whom the U.S. Navy is at a firepower disadvantage, munitions-like unmanned vessels offer an asymmetric sea denial capability that ships do not. This is true of the Indo-Pacific Command theater, where the People’s Liberation Army Navy has a local firepower advantage over the U.S. Navy west of the first island chain. Therefore, a focus on massed unmanned munitions, not ships, is what the U.S. Navy needs for its fleet in the Western Pacific.

Being Specific: Unmanned Surface Vessels as Ships Versus Munitions

When many people refer to unmanned surface vessels, they are describing ship-like surface combatants the size of a patrol vessel, a corvette, or a small frigate. To date, a significant portion of the U.S. Navy’s unmanned surface vessel development efforts have been on these types of platforms. Its 2021 Unmanned Campaign Plan, the most recent official document describing the U.S. Navy’s unmanned strategy, refers to large and medium unmanned surface vessels in this context. The U.S. Navy sees these types of low-end ships as a core part of a high-low force structure, with the most recent shipbuilding plan calling for a significant number of small, ship-like unmanned vessels. Its solicitation for new contracts on the concept, known as the Modular Attack Surface Craft, appears to confirm that it is intent on building these kinds of platforms.

The advantage of unmanned, low-end ships is that they can bolster the fleet’s end strength and add to its missile firepower, thus helping the U.S. Navy disaggregate its forces. Under the logic of distributed lethality (also commonly known as distributed maritime operations), having more small, cheap combatants both adds more missile inventory to the fleet and makes it harder for adversaries to target and destroy large portions of the U.S. Navy’s offensive capability with just a few anti-ship missile hits.

Many who favor building ship-sized unmanned surface vessels believe that they would be an economical solution to growing the fleet, with the idea of “deconstructing” expensive units. This would entail foregoing the construction of at least a few large, multi-mission ships and instead buying a larger number of smaller vessels, which together can accomplish the same missions as the larger combatants. Against anti-ship missiles, proponents of ship-like unmanned vessels believe they would be relatively expendable and thus could be used in a conflict to attract the first volley of anti-ship missiles in lieu of the U.S. Navy’s more valuable legacy platforms.

These arguments notwithstanding, the discussion around unmanned surface vessels has rarely made a clear distinction between unmanned ships and smaller vessels that behave like something closer to a munition. Many munition-like unmanned surface vessels resemble small speedboats, but their method of attack is more similar to mines than to ships. As such, they should be thought of and employed differently than ships, more like mobile naval mines that can quickly transit to a patrol area and either detonate or persist in that area until commanded to move or detonate.

The mine-like nature of unmanned surface munitions gives them several unique advantages. Among these are the greater range at which they can be employed, their extreme expendability, the prospect of their mass production, and their survivability against missiles.

Although lessons about drone use in the Russo-Ukrainian War should not be overstated, Ukraine’s success using small, one-way attack surface drones against Russia illustrates that they can be controlled remotely even in contested environments. This implies that if assured command and control can be maintained, controlling stations could remain well outside weapons engagement zones — the geographic areas in which legacy ships are most vulnerable.

Some critics might object to this on the grounds that assured command and control cannot be guaranteed in contested environments, which also relates to questions of how much autonomy the platforms should have and how they perform target discrimination. While this is a valid concern, the challenge is manageable. With the prospect of resilient micro-satellite communications links that can withstand anti-satellite attacks, the threat to the control network as a whole could soon be much lower than it is today. Local control signal jamming could still be a threat, but naval analyst Bryan Clark points out that autonomous technology available today for these systems would be sufficient for continuous, effective operations. Even in the event of local signal jamming, unmanned surface munitions could navigate to pre-programmed positions using onboard inertial navigation and then find, fix, and finish targets using onboard seekers. This level of autonomy would be like that of a naval mine or an aerial missile, which the U.S. military already understands well from a legal and ethical perspective.

In terms of expendability, unmanned surface munitions are explicitly designed to be used in combat to attack the enemy, so there would be even less risk aversion to employing them in dangerous areas than there would be to employing ship-like unmanned vessels. Their extreme expendability also means there are fewer operational problems to consider compared to unmanned surface ships, such as the challenge of repairing, refueling, and rearming at sea.

Unmanned surface munitions are an example of precise mass, and as such, they have a lower barrier to mass production than unmanned ships. They are smaller and less complex than ships, lending to simpler designs with more commercial and off-the-shelf components. While the U.S. Navy has faced challenges with some of its unmanned ship development and testing efforts, the technical hurdles to developing and employing munitions-like platforms are less significant. As demonstrated by Ukraine’s employment of one-way attack drones, it is possible to develop, build, and deploy unmanned surface munitions at scale even in relatively austere wartime environments. The U.S. defense industrial base could begin developing and deploying them quickly, and importantly, it could do so without disrupting the valuable production lines of any of its large, multi-mission ships. Indeed, the United States appears open to partnering with newcomers to the defense industry to invest in massed munition-like platforms: Saronic, a private firm, recently secured a $392 million contract to build small, unmanned surface craft for the U.S. Navy.

Finally, unmanned surface vessels are much less susceptible to anti-ship missiles than ships that are corvette-sized or larger. This is simply due to their smaller hull form and lower radar cross-section. And even if they are targeted, they would likely cost less per unit than comparable advanced anti-ship missiles. Ukraine’s already familiar Magura and Sea Baby families of unmanned surface munitions cost less than $300,000 per unit, although their range is relatively limited. Saronic’s long-range vessel Corsair, which today is priced at about $1.2 million per unit, could be fitted with a warhead for only a little more than that and would remain an asymmetrically cheap option, such that shooting these vessels with an advanced anti-ship missile would still be uneconomical. This advantage over anti-ship missiles is perhaps the most important factor when considering whether to employ unmanned surface munitions in a potential conflict with the People’s Republic of China.

Ships or Munitions? Thinking Through the Adversary’s Advantages

The decision on whether to employ unmanned ships or unmanned surface munitions in any given scenario will depend on the capability they need to provide and on the threat. This is not to say that the U.S. Navy should exclusively develop one or the other, but that certain types of unmanned vessels are better suited for certain adversaries or within specific geographies. Ship-like platforms might be more appropriate in some threat environments but inappropriate in others, and vice versa for unmanned surface munitions.

In the case of the Western Pacific theater, the U.S. Navy is preparing for the sea denial mission against the People’s Republic of China, which fields a precision strike network designed to prevent U.S. intervention in the theater by overwhelming the defenses of U.S. warships with masses of advanced anti-ship missiles. Given the mission and the threat environment, unmanned surface munitions are better suited for this theater than missile-shooting unmanned ships.

Adding unmanned ships to the fleet may help the U.S. Navy to distribute its offensive firepower, but it plays into China’s primary strength: its precision strike network that is explicitly designed to find, fix, and finish U.S. Navy warships using salvos of high-end anti-ship missiles. In combat, the U.S. Navy would have a difficult time defeating this network because of the realities of the salvo model of modern missile combat. Often associated with the late Capt. Wayne Hughes, this model describes how naval missile combat is decided arithmetically by comparing salvo size and defensive capacity of each side. It predicts that with all other factors like reconnaissance capability or missile quality being equal, a disadvantage in one force’s missile salvo capacity compared to that of the other can lead to massive losses.

While notoriously difficult to quantify with exactitude, China would likely have a significant advantage over the United States in a missile salvo exchange. According to the 2025 Department of Defense report on Chinese military power, China has the world’s largest hypersonic missile inventory, its missile industry produces products that are comparable in quality to those of other top-tier producers, and it continues to advance its intelligence, surveillance, and reconnaissance capability to be able to target U.S. assets effectively. China’s navy already has a significant local advantage in shipboard vertical launch system cells — typically used by analysts as a measure of relative maritime strength — when compared with the number of U.S. surface combatants attached to the U.S. Seventh Fleet.  Using the high end of 14 U.S. Navy Arleigh Burke destroyers in theater yields 1,344 vertical launch system cells compared with 2,944 cells within the People’s Liberation Army Navy (896 cells from China’s eight Type 055 cruisers and 2,048 cells from its 32-type 052D destroyers). This does not count the smaller vertical launch cells on China’s Type 054A/B frigates — add these and the box-launched missiles carried aboard China’s smaller naval combatants to this calculation, as well as the People’s Liberation Army Rocket Force’s anti-ship ballistic missiles and land-based cruise missiles, and China’s total anti-ship missile advantage over the United States is even more lopsided.

The U.S. Navy would need to have a comparable number of missiles as Chinese forces in a salvo exchange and would need to successfully target China’s relevant missile shooters for the exchange not to result in a sharp defeat of U.S. forces. If unmanned surface ships armed with missiles are intended to help the U.S. Navy restore missile salvo balance, they are unlikely to do so. Corvette-sized unmanned surface vessels are still vulnerable to being targeted from the air, so even if the U.S. Navy succeeded at building a 500-ship force comprised partially of small unmanned combatants that the 2025 shipbuilding plan calls for — only about a 1.7 times increase in hulls from today’s fleet — it would not change the anti-ship missile salvo balance given China’s massive advantage. The U.S. Navy would simply not be able to build enough hulls to make much of a difference.

Potential Solutions to Missile Disadvantage

Unmanned surface munitions are better suited for a sea denial mission against an adversary with a missile firepower advantage. Thanks to their unique benefits, especially their lower susceptibility to anti-ship missiles, they are an asymmetric, offsetting option. China would not be able to use its biggest strength against them effectively. And like mines, they can be deployed to persist in the maritime domain until activated, which could help create doubt in the minds of China’s military planners.

One concern about employing unmanned surface munitions in a Western Pacific fight is the vast size of the theater and whether unmanned surface munitions would have enough endurance to be effective. However, like the assured command and control concern, this is another problem that new technology is beginning to solve. With the latest models of small unmanned vessels like the aforementioned Corsair offering a 1,000 nautical mile range, they could reach the South China Sea or East China Sea if they were launched from forward bases in the theater or even from manned surface vessels operating just outside the range of most of China’s anti-ship missiles.

The U.S. Navy will need to build both kinds of unmanned surface vessels — ships and munitions — to maximize its sea denial capability. Nothing stated here is meant to be an argument against building more ships. But to employ their forces properly, U.S. planners need to understand that there is a big difference between the two kinds of unmanned surface platforms in terms of what they can do. There is already precedent for the United States military thinking about unmanned platforms in this way. Indo-Pacific Command’s “Hellscape” concept emphasizes the use of expendable, munitions-like drones of all kinds to slow an invasion of Taiwan. That the U.S. military is pursuing such a concept indicates that it recognizes the value of focusing on munitions-like unmanned platforms in the Western Pacific theater.

Conclusion

As China began modernizing its military in the 1990s, People’s Liberation Army Gen. Zhang Wannian advocated for prioritizing the development of asymmetric weapons to blunt U.S. military dominance in the western Pacific: “Our funds are limited, our time is constrained, and we cannot do everything… What the enemy is afraid of, we develop that.” The U.S. Navy can learn a lesson from Zhang as it works out how to develop unmanned vessels.

Beijing would be most afraid of losing the advantage it has today from its anti-ship missiles. Blunting that advantage with unmanned systems will require maximizing the benefits they can offer against anti-ship missiles while minimizing the drawbacks. Unmanned surface vessels that resemble munitions rather than ships would be the more effective tool to counter this threat.

The first step to unlocking their potential asymmetric advantage is to make the distinction between the two types of systems. A more precise taxonomy could clarify the functions that each type of unmanned surface vessel is meant to perform and help identify the roles that each should play in the sea denial mission.

Aaron Marchant is an active-duty submarine officer in the U.S. Navy. He is currently serving as the U.S. Navy federal executive fellow at the Center for Strategic and Budgetary Assessments in Washington, DC, where his research focuses on naval strategy.

The opinions expressed are those of the author and do not reflect the views or policy of the U.S. Defense Department, the Department of the Navy, nor the U.S. government. No federal endorsement is implied or intended.

**Please note, as a matter of house style, War on the Rocks will not use a different name for the U.S. Department of Defense until and unless the name is changed by statute by the U.S. Congress.

Image: U.S. Naval Forces Southern Command/U.S. 4th Fleet via DVIDS.