【Cooperation between European and Indo-Pacific Powers in the US alliance system project：Policy Paper Vol. 2】
Embracing Hybrid Fleets: Using Uncrewed Systems to Field More Effective and Sustainable Allied Navies

Publication of Policy Papers for the SPF Project “Cooperation Between European and Indo-Pacific Powers in the U.S. Alliance System”

　IINA (International Information Network Analysis) hosts a series of policy papers featuring analyses and insights from U.S., Japanese, South Korean, Australian and European experts, which discuss constructive cooperation among U.S. allies in Europe and the Indo-Pacific. The series aims to provide readers with valuable perspectives on the future of NATO-IP4 (Indo-Pacific 4) cooperation for regional and global security.

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Allied navies face challenges on multiple fronts. At sea, they are stretched thin while responding to continued gray-zone aggression and defending global shipping from drone and missile attacks.[1] At home, industrial and demographic constraints hinder them from crewing and sustaining their fleets.[2]

More money and policy support could help navies mitigate these challenges but would not tackle the root cause of shrinking and uncrewed fleets: force designs that emphasize large, multimission crewed ships and aircraft over uncrewed systems and less sophisticated vessels.

Allied navies are wedded to a set of crewed platforms whose costs preclude buying larger numbers of smaller, less expensive ships or aircraft that could restore the fleet’s capacity. To stay ahead of potential competitors, allied navies—including those of AUKUS—are considering next-generation destroyers and submarines that would be even more expensive and complicated than their predecessors. The result will be smaller, less adaptable fleets.

Allied navies could pull out of this downward spiral by embracing more heterogeneous fleet designs. Rather than continuing to field a shrinking force of exquisite ships and aircraft, they would field larger forces of crewed and uncrewed platforms. These fleets would gain advantages over opponents through their payloads and ability to combine in a diverse array of changing effects chains across domains. By shifting complexity from inside individual ships and aircraft to the kill chains between them, allied fleets could gain decision-making advantages over opponents while generating capacity or capability when and where they need it.

Using uncrewed vehicles will be essential to fielding larger, more heterogeneous fleets.[3] A wide array of uncrewed systems can be relevant in high-end conflict while offering dramatically lower costs of procurement and—most importantly—sustainment. By decomposing some functions of traditional crewed platforms into uncrewed systems, navies could gain scale at lower costs than through crewed ships or aircraft. And although uncrewed systems are not completely unmanned, their personnel needs do not grow linearly with the number of vehicles like those of crewed ships or aircraft.

The US Navy is pursuing uncrewed systems through an accelerating set of efforts to create what uniformed leaders call a “hybrid fleet.”[4] These initiatives—including Task Force 59 in the Middle East,[5] 4th Fleet in Central and South America,[6] and the Integrated Battle Problems in the Indo-Pacific[7] —are great examples of applying new technologies to thorny operational problems. But allied navies need to go further and stop treating uncrewed systems as merely additive to the crewed force.

With an appropriate command, control, and communication architecture, uncrewed platforms and vehicles can enable any of the links in a kill chain. Rather than being extensions of crewed platforms that provide greater reach or persistence, uncrewed systems can replace crewed ships and aircraft in many functions and allow operators to focus on decision-making.

A growing number of experiments and real-world operations are demonstrating the effectiveness of uncrewed systems. After losing its navy to attack or capture, Ukraine’s military restored access to vital shipping lanes by pushing the Russian Black Sea Fleet to the far side of Crimea using uncrewed attack boats and undersea vehicles.[8] Houthi rebels are mounting a sustained counter-maritime campaign using a combination of Iran-supplied drones and cruise missiles.[9] Although US Navy destroyers largely defeated them, the threat of attacks across the Red Sea has disrupted shipping patterns and scrambled supply chains between Europe and Asia.

Recent US Navy Integrated Battle Problems have learned from what the Ukrainian military and Iranian proxies have done and are experimenting with concepts that could create a “hellscape” for Chinese invaders in the Taiwan Strait.[10] By attacking troop transports and their escorts with drone boats, undersea vehicles, and loitering munitions, a force of mostly uncrewed systems could slow or disrupt the invasion. These systems would give US and allied forces targeting information and time to destroy Chinese ships with long-range missiles and torpedo fires.

Rather than being a near-term fix for the challenge of stopping a short-notice Chinese invasion of Taiwan, an uncrewed force like this one could be a valuable hedge against what is otherwise a high-consequence, low-probability scenario. A recent Hudson Institute study highlights the potential importance of these hedge forces in future defense planning.[11] By addressing the most difficult aspects of the invasion scenario, a force like that in Admiral Samuel Paparo’s hellscape could allow the US Navy to arrest the ongoing distillation of the fleet into a small number of submarines, destroyers, and carriers that can launch anti-ship missiles into the Taiwan Strait.[12]

Beyond surface warfare, the utility of uncrewed systems in surveillance, targeting, or attack shows they can lower the costs of steady-state operations and unlock wartime scale. Navies have used uncrewed systems for decades in ASW,[13] from Cold War–era Sound Surveillance System (SOSUS) arrays to deployable sensors like the Transformational Reliable Acoustic Path System (TRAPS).[14] Most recently, they have used MQ-9B Reapers to manage sonobuoy fields[15] and medium uncrewed surface vessels to tow sonars.[16]

By shifting most steps of the ASW kill chain to uncrewed systems, allied navies could realize the scale and persistence they need against modern submarine threats and reduce the risk P-8A Poseidon maritime patrol aircraft or destroyers would face while operating near contested chokepoints. Moreover, using uncrewed vehicles for ASW sensing and tracking would free these platforms and attack submarines to conduct other crucial missions in a confrontation against a submarine-equipped adversary like China or Russia.

Uncrewed systems would also improve the ability of allied submarines to conduct offensive operations by suppressing and defeating undersea defenses.[17] Like their counterparts above the water, submarines will increasingly need to rely on offboard decoys, jammers, or attack vehicles to counter the sonar arrays and mines that opponents like Russia and China are installing around their most valuable targets.

The Houthis’ success in hindering Red Sea shipping shows the value of uncrewed systems in surface warfare. But efforts to counter the Houthi drone and missile threat also highlight the need for new approaches to sustainable air defense. Naval vessels may still need to use sophisticated surface-to-air missiles, like the SM-2 or Evolved Sea Sparrow Missile (ESSM), against high-end cruise and ballistic missiles. However, allied navies could use uncrewed aircraft like the Anduril Roadrunner[18] or Raytheon Coyote[19] to shoot down drones or subsonic missiles. And uncrewed surface vessels could be decoys that confuse enemy targeting or misdirect incoming weapons.

The air and submarine threats to naval forces are probably most acute for logistics operations, which often place lightly defended ships in highly contested areas where they need to support troops and other vessels. Uncrewed systems could help alleviate the risk of contested logistics operations by reducing the number of personnel necessary for refueling and resupply missions. More importantly, smaller uncrewed systems could be inexpensive enough to field in large numbers, enabling distribution of logistics operations to lower the impact of losing any particular support ship or aircraft to enemy fire. The US Marines relied on uncrewed aircraft like the K-Max to support operations in Afghanistan.[20] Today the service is already experimenting with upgraded drones and a new Long-Range Uncrewed Surface Vessel,[21] which could also be armed to provide fire support to troops ashore.

These are just a few examples of how uncrewed systems already in the field or in prototype form could help naval forces depend less on sophisticated crewed platforms. But only by making uncrewed systems full members of the force—rather than “loyal wingmen,”[22] adjunct magazines,[23] or uncrewed teammates[24] —can navies avoid future costs that will otherwise continue to shrink their fleets and leave them less agile. Because the relevant technologies are largely available, navies no longer need to rely on predictive analytics to guide decades-long development projects. Instead, capability development should focus on combining existing systems and tactics to solve contemporary problems.[25]

In an environment where their dominance is no longer a given, allied navies need to return to operational innovation. And their force designs will need to provide the kind of flexibility that can support creative problem-solving. Many of the pieces and processes the allies need to enable effective innovation are emerging from industry, service labs, and collaborative experimentation. Accelerating and realizing the benefits of uncrewed systems will require militaries to orchestrate better and execute these activities more effectively to solve today’s operational problems. If allied navies fail to do so, they may miss their best opportunity to gain an enduring advantage against their technologically empowered opponents.

(2025/03/14)