The Naval Air Warfare Center Weapons Division has shared details of a US Navy USV robotic refuelling demonstration that transferred 400 gallons of fuel to a drone boat without placing any sailors aboard the receiving vessel, a step the Navy says could extend the operational endurance of uncrewed surface vessels (USVs) in higher-threat waters.
From concept to water in seven months
The demonstration involved the T38 USV, a Navy-owned remotely controlled vessel built by Maritime Tactical Systems Inc. (MARTAC), and a towable capture-and-connection device (TCCD) made by Sealartec. According to Ocean News, the exercise was sponsored by US Fleet Forces Command, Naval Surface Warfare Center Dahlgren Division, and Naval Surface Warfare Center Carderock Division, and took place in waters off Joint Expeditionary Base Little Creek-Fort Story in Virginia.
What makes the programme’s pace worth noting is the timeline. The Navy-industry team moved from concept to real-world testing in seven months, according to Ocean News and MARTAC. During that period, the T38 and the Sealartec TCCD completed dozens of capture, refuel, and release cycles, transferring a total of 400 gallons across those runs.
The Sealartec system is formally designated the Autonomous Replenishment at Sea (A-RAS). MARTAC states that the fuel transfer was achieved by deploying the A-RAS from the stern of a surrogate platform, with the T38 then manoeuvring to capture, connect, and receive fuel before releasing and resuming its course.
US Navy USV robotic refuelling: the operational problem it solves
The immediate driver behind the programme is the Navy’s testing of hypersonic and other long-range weapons. Spencer Holloway, director of the division’s Blue Water Instrumentation Future Capabilities Office, explained in a release that those tests, ‘where flight profiles can extend thousands of miles beyond fixed-range boundaries,’ can ‘require data-collection assets to be distributed across a vast area.’ Naval drones are well-suited to gathering that distributed data, but the need to return to port for fuel reduces their time on station.
‘Every time an unmanned vessel must return to port for fuel, we lose persistence, reduce coverage and redundancy, and interrupt the mission,’ Holloway said. The robotic refuelling capability is designed to break that constraint, allowing a USV to remain on station longer and farther from any support infrastructure.
Ronald Raymer, branch head for capability, innovation, science and technology integration at US Fleet Forces Command, set out the broader force-structure argument in the same release. ‘This will allow us to have greater reliance on unmanned vessels instead of manned, and we can push the USV into higher threat areas without risking manned vessels and personnel,’ he said. Raymer added that the capability ‘will also allow us to distribute greater capability into an area without having to invest in large expensive manned vessels.’
What comes next: full end-to-end autonomy
The August demonstration was not fully autonomous. Operators retained control at various points in the sequence, and the Navy describes it as a step toward, rather than the completion of, a wholly autonomous refuelling cycle. The next milestone the Navy is working toward is a complete end-to-end test in which the drone boat meets the refuelling system, approaches it, connects, takes on fuel, disconnects, and returns to its mission without operator input at any stage.
Holloway said that reaching that milestone will require more precise maneuvering from both systems and better local positioning capability. Those are engineering challenges rather than conceptual ones, which puts the programme in a relatively advanced position given the seven-month run from idea to water. The Navy has not stated a timeline for the end-to-end autonomous test.