MARTAC, Navy demonstrate first autonomous USV refueling at sea

MARTAC and a Navy-industry team completed the first known fully autonomous unmanned surface vessel refueling at sea during an August demonstration off Virginia. The test points to longer-endurance USVs that can stay on station longer and support distributed maritime operations without returning to port for fuel.

Why it matters: - At-sea refueling removes a major endurance limit for unmanned surface vessels. - The capability can keep USVs on station longer and extend the reach of distributed maritime operations. - The approach reduces the need to send crewed support ships into higher-threat waters. - The demonstration also suggests a path to autonomous refueling between unmanned platforms in future operations.

What happened: - MARTAC announced the successful refueling of a USV at sea with a joint Navy-industry team. - The fuel transfer used Sealartec’s Autonomous Replenishment at Sea, or A-RAS, refueling system. - The A-RAS system was deployed from the stern of a surrogate platform. - The test refueled a MARTAC Devil Ray T38 owned by the Naval Air Systems Command Naval Air Warfare Center Weapons Division Blue Water Instrumentation program. - The demonstration took place in August off Joint Expeditionary Base Little Creek-Fort Story, Virginia. - The team repeatedly captured, refueled and released the Navy-owned Devil Ray T38 while underway. - The system also completed pier-side events during the trial. - The team transferred a total of 400 gallons of fuel. - The system completed about 100 connection cycles in the days before and during the demonstration.

The details: - The refueling used Sealartec’s towable capture and connection device, or TCCD. - The TCCD was towed astern of the training support vessel USNS Vindicator (TSV 5). - The team ran dozens of full-cycle capture, refuel and release evolutions. - MARTAC said the capability moved from concept to water in seven months. - MARTAC, NAWCWD’s BWI program and Sealartec worked as a single integrated team. - The effort used contracting authorities built for speed. - The Navy selected the Devil Ray T38 after market research for its stability and endurance. - The T38’s catamaran hull form provides a stable sensor platform for range instrumentation and the alignment needed for the TCCD to capture and connect. - The demonstration was sponsored by U.S. Fleet Forces Command, Naval Surface Warfare Center Dahlgren Division and Naval Surface Warfare Center Carderock Division. - The event brought together BWI, BWI’s Future Capabilities Office fleet management team, MARTAC and Sealartec. - The Littoral Combat Ship Mission Modules Program Office, PMS 420, and the Navy’s Portfolio Acquisition Executive for Robotics and Autonomous Systems provided contracting support. - MARTAC said its Naval Sea Systems Command Production Other Transaction Authority helped compress seven months of development into demonstrated capability.

Between the lines: - The test shows how faster contracting and closer Navy-industry integration can shorten development cycles. - The repeated capture and connection cycles matter because autonomous refueling has to work reliably, not just once. - The Navy’s interest in a stable platform suggests the refueling problem is as much about control and alignment as it is about fuel transfer. - Sealartec framed the result as evidence that defense organizations can operate with more startup-like speed when procurement barriers are reduced. - MARTAC framed the effort as a model for how government and industry can iterate together in an operational environment.

What's next: - MARTAC said the next step is refueling across distance. - MARTAC’s Leviathan T82 is scheduled for delivery in spring 2027. - The Leviathan T82 is being developed as a mid-size workboat with a cruising range of 4,000 nautical miles. - The platform is intended to act as a tanker on the seas and provide autonomous USV-to-USV refueling for properly configured USVs. - MARTAC linked the work to broader efforts to extend the range and endurance of unmanned platforms within a hybrid fleet.

The bottom line: - The demonstration moves autonomous naval logistics from theory toward operational use and gives the Navy a tool that could keep unmanned vessels deployed longer and farther from port.