Powering Sea Archer: Twin 300 V8 Diesel Outboards for the Australian-Built USV

The recent on-water trials of Sea Archer mark an important milestone in the evolution of uncrewed surface vessels (USVs) and autonomous maritime systems, and a proud moment for all partners involved in bringing the platform to life. Developed by Leidos Australia, its first locally built uncrewed surface vessel (USV) is a powerful demonstration of what can be achieved through innovation, collaboration and advanced autonomous marine propulsion.

A key contributor to Sea Archer’s propulsion capability is Power Equipment (PE Outboards), Cox Marine’s Australian distributor, which supplied twin Cox 300 V8 diesel outboards for the vessel. The integration of these high torque, high endurance engines highlights the importance of regional expertise and trusted partnerships in delivering leading USV propulsion solutions to local markets.

At the heart of Sea Archer’s performance, the Cox 300 V8 diesel outboards deliver the reliability, efficiency and endurance required for extended, mission-critical operations. As trials progress in real-world conditions, the focus remains on validating essential performance metrics such as handling, system behaviour and overall operational capability in autonomous USV environments.

With a range of up to 1,500 nautical miles, Sea Archer has been engineered for persistence and adaptability. Its versatile design allows it to support a wide range of operational roles, from surveillance and logistics resupply to more complex and evolving mission profiles. That level of flexibility is increasingly vital in a maritime environment where autonomous vessels and USVs must respond to dynamic mission requirements.

For Cox Marine, this project highlights the growing role of high-performance diesel outboards in next-generation vessel design, particularly within the uncrewed and autonomous space. Efficiency, durability and reduced fuel consumption are critical factors when endurance is paramount, and when access for servicing or refuelling may be limited. The integration of Cox propulsion technology into a platform like Sea Archer reflects the increasing demand for systems capable of supporting long-endurance USV operations with minimal intervention.

The involvement of PE Outboards demonstrates the importance of a strong network of regional partnerships, bringing together global engineering expertise with local knowledge ensures that platforms are innovative, robust, supportable and fit for purpose in their operating environments.

While Sea Archer’s trials are focused on proving technical performance, they also represent something broader: a shift in how maritime capability is delivered. Uncrewed platforms offer significant advantages, from reducing risk to personnel to enabling deployment in more challenging conditions. When paired with dependable propulsion, they unlock new possibilities for operators across defence, security and commercial sectors.