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The global unmanned surface vessel (USV) market is booming, with analysts valuing it at over $2 billion in 2024 and projecting growth to more than $3 billion by 2030. Navies, coastguards, and commercial operators are deploying USVs for tasks from surveillance to mine countermeasures, and governments worldwide are investing heavily in these systems.
This expanding market drives demand for propulsion systems that deliver long endurance, high reliability and low operating cost. Cox Marine’s diesel outboard technology is uniquely suited to USVs, combining proven industrial robustness with easy integration.
Diesel outboard advantages for USVs
Cox Marine’s diesel outboards offer significant technical advantages for unmanned surface vessels operating in complex environments. Firstly, they provide spark-free safety. Unlike petrol engines, diesel units use compression ignition, which eliminates the risk of explosion – a key benefit in hazardous or regulated zones. This makes the Cox V8 a compliant and inherently safer option for offshore and military applications where petrol engines are often banned.
Secondly, Cox’s twin-turbo diesel outboards produce exceptionally high torque at low RPM. With peak torque delivered at just 2600 RPM, the V8 ensures smooth acceleration and responsive handling even in challenging sea states. This low-end torque allows USVs to manage heavy payloads and navigate strong currents with ease.
The third advantage is extended range. Diesel fuel’s higher energy density, combined with Cox’s engine optimisation, yields up to 30% better fuel economy compared to petrol alternatives. This translates into significantly longer mission durations and fewer refuelling stops – critical for extended patrols or offshore surveys.
Finally, Cox outboards are designed for low maintenance and high uptime. Built for continuous commercial use, the V8 offers extended service intervals and easy maintenance access. Supported by Cox Marine’s global service network, operators can count on responsive parts supply and technical assistance wherever they deploy, keeping their USVs operational and ready.
Engineered for endurance
The Cox 300 and 350 V8 diesel outboards are engineered to deliver exceptional endurance and reliability for autonomous marine systems. These engines generate between 959 and 1052 Nm of torque – roughly double that of comparable petrol outboards – thanks to a robust twin-turbo V8 configuration. Achieving peak torque at just 2600 RPM, they offer powerful, controlled acceleration even under heavy load, making them particularly well-suited to high-speed USVs and rapid-response platforms.
In addition to performance, the Cox V8 delivers unprecedented fuel efficiency. Its compression-ignition design improves fuel economy by at least 30% over petrol equivalents. For unmanned vessels, this means more nautical miles per mission or more hours on station, significantly enhancing operational range and endurance.
What truly sets the Cox V8 apart is that it is purpose-built for marine use. It is the world’s first V8 diesel outboard designed specifically for boats, not repurposed from automotive platforms. Fully certified to EPA Tier 3, RCD II and IMO II standards, and built with marine-grade materials, it simplifies both new installations and repowers with its universal transom mount. The result is a durable, efficient, and easy-to-integrate propulsion solution – perfectly aligned with the demands of today’s unmanned surface vessels.
Pioneering projects: MARTAC and Phoenix USVs
Cox diesel outboards have powered USV programs since their early days. In 2023 Maritime Tactical Systems (MARTAC) unveiled its Devil Ray T24 ASV – a 7m high-speed USV – equipped with twin Cox 300 V8 diesel outboards. This craft can sprint at over 50 knots and cruise 600 nautical miles, carrying 1,800 lb of payload. The use of Cox engines in MARTAC’s USVs underscores Cox’s role as a partner in high-performance unmanned platforms.
In the Middle East, Cox Marine is again at the forefront of innovation. The Phoenix USV, built by UAE companies DeepTrek and Blue Gulf Cat, was recently launched using Cox Marine outboard engines. This state-of-the-art 43ft catamaran was revealed at Abu Dhabi’s NavDex 2025, with Cox Marine providing “advanced diesel outboard engines for extended-range operations”.
By powering the Devil Ray, Phoenix, and similar projects, Cox Marine is demonstrating how diesel outboards enable next-generation unmanned vessels to meet the rigorous demands of defence and security missions.
Cox Marine’s leadership and support
Cox Marine is a leader in the unmanned surface vessel propulsion sector through a combination of advanced diesel outboard technology, marine-specific engineering, and global operational support. The company’s diesel outboards are designed to meet the harsh demands of unmanned operations, where performance, endurance and reliability take priority.
With high torque at low RPM, exceptional fuel efficiency, and robust marine-grade construction, Cox engines provide the dependable power USV operators need in the field. Integration is made straightforward through open CANbus architecture and NMEA 2000 compatibility, allowing seamless connection to autonomous control systems.
Cox Marine also stands out for its global support infrastructure. Unlike many niche engine manufacturers, Cox controls its own production and supply chain, ensuring consistent availability of engines and critical components.
The company’s international distributor network and experienced in-house service teams offer reliable, regionally accessible support, helping operators minimise downtime and maintain readiness. This comprehensive approach to product quality, integration and aftersales service has established Cox Marine as a trusted propulsion partner for USV developers and operators around the world.
Propel your USV programs with Cox Marine
Cox Marine is committed to the future of autonomous marine systems. Our diesel outboard engines have proven themselves in challenging defence and commercial projects worldwide.
For USV developers and operators seeking reliable, high-endurance propulsion, Cox Marine offers tailored solutions and expert support.
Contact your local Cox Marine representative today to discuss how our diesel outboards can power your next USV project with unmatched performance and reliability.
