The partnership brings together Fleetzero’s Leviathan™ Battery Energy Storage System, propulsion technologies, and autonomy stack, with Thoma-Sea’s domestic shipbuilding capacity and Glosten’s vessel design expertise. The three companies are developing a tightly integrated autonomous diesel-electric vessel engineered for use in contested waters, persistent operations, and supply delivery with minimal radar cross-section. Its angular design draws inspiration from low-profile and stealth vessels in military use today, and elevates the propulsion technology for long-range, low-signature missions.
The combined capability has been refined through demonstrations and engineering work with organizations across the maritime sector and is engineered to address requirements outlined in areas of interest for the Defense Innovation Unit (DIU) and other Department of War stakeholders. The integrated platform showcases how electrified propulsion paired with autonomous vessel control enhances operational effectiveness across contested littoral and blue-water environments, while delivering the supply chain resilience that commercial and government customers require.
The collaboration aligns with Department of War, MARAD, and Coast Guard priorities, including the Modular Open Systems Approach (MOSA). The combined platform addresses a wide range of operational needs, including:
- Autonomous and remotely operated cargo operations
- Persistent ISR, patrol, and contested logistics missions
- Electrified harbor craft, tugs, and coastal vessels
- Improved operator safety
- Domestic-content, Jones Act, and Buy American compliance
Electrifying and Automating the Maritime Fleet
As the US Department of War, MARAD, and allied maritime forces accelerate adoption of autonomous and remotely crewed surface vessels, the ability to deliver electrified, autonomy-ready hulls from domestic shipyards is becoming a national priority. The Fleetzero, Thoma-Sea, and Glosten collaboration directly supports this objective by combining ultra-dense marine energy storage, vessel-level autonomy, and US shipbuilding into a single low-signature platform.
“Moving cargo through contested waters is more imperative today than ever before. Fleetzero is building and demonstrating that capability today,” said Steven Henderson, CEO of Fleetzero. “By partnering with Thoma-Sea and Glosten, we are pairing our Leviathan™ Energy Storage Systems and Fleetzero’s autonomy stack with two of the most capable shipbuilding and design organizations in the country. This is how we can deliver MOSA-compliant, autonomous vessels at scale.”
Fleetzero’s autonomy strategy began with improving the propulsion system, a key enabler for eliminating maintenance required while in autonomous mode. Fleetzero’s diesel-electric propulsion with the Leviathan™ Battery System unlocks long-duration autonomy missions. Fleetzero’s Leviathan™ Battery Systems provide minimal noise and heat signature, engineer out unnecessary parts, and typically deliver double the energy density compared to other maritime battery systems. This reduces the total bill of materials to manufacture at scale, and dramatically cuts operating expenses over the vessel’s lifespan while enhancing reliability and survivability in contested waters.
Extending Mission Reach Through American Shipbuilding
Thoma-Sea Marine Constructors, founded in 1989 and based in Houma, Louisiana, operates new construction yards in coastal Louisiana. Thoma-Sea was selected by the US Navy’s Naval Sea Systems Command to design and build the NOAA Oceanographer-class research vessels under a $178 million contract, and has delivered Navy-administered Foreign Military Sales vessels for allied customers. By integrating Fleetzero’s power and autonomy systems into Thoma-Sea built hulls, the collaboration delivers a domestically built, autonomy-ready vessel that meets Jones Act and US-content requirements for federal customers.
“Our yards have been building ships for American operators for decades,” said Walter Thomassie, Managing Director of Thoma-Sea. “Partnering with Fleetzero and Glosten allows us to deliver the next generation of autonomous vessels with stealth capabilities ready for the missions our customers face today.”
Glosten brings more than six decades of naval architecture and marine engineering experience, with a portfolio spanning research vessels, commercial cargo ships, and government platforms. As the lead naval architect for the system, Glosten integrates Fleetzero’s propulsion and autonomy technologies with Thoma-Sea built hulls, engineering the platform’s defining capabilities: low radar cross-section, silent transit, beach approach angles, and autonomous self-withdrawals.
“Bringing autonomy and electrification together at the vessel-design level is where this collaboration creates real value,” said Morgan Fanberg, CEO of Glosten. “Working with Fleetzero and Thoma-Sea, we are designing vessels that are autonomy-native from the keel up, not retrofitted as an afterthought. The design is both functional and low-signature, built for decades of deliveries in the years ahead.”
Backed by Momentum and Investment
This announcement follows a period of significant momentum for Fleetzero, which closed a $43 million Series A funding round in 2025. Fleetzero has been backed by both technology and shipping titans such as 8090 Industries, Y Combinator, Founders Fund, Obvious Ventures, Maersk Growth, and MOL Plus. The investment supports continued growth, advanced research and development at Fleetzero’s Houston headquarters, as well as expanded partnerships such as the collaboration with Thoma-Sea and Glosten to bring next-generation electric autonomous vessel capabilities to market faster.
Fleetzero, Thoma-Sea, and Glosten are positioned to help shape the next era of maritime operations, where electrified power, autonomous control, and American shipbuilding operate as a unified industrial base.
