Fleetzero is collaborating with Thoma-Sea Marine Constructors and Glosten to develop an integrated autonomous vessel platform for commercial, government, and defense customers, targeting contested waters and persistent operations with a minimal radar cross-section.
The collaboration is built around combining Fleetzero’s Leviathan Battery Energy Storage System and autonomy stack with Thoma-Sea’s domestic shipbuilding capacity and Glosten’s vessel design expertise.
What the partners are integrating into one platform
The partnership combines 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 development effort is focused on a tightly integrated autonomous diesel-electric vessel intended for supply delivery, contested waters, and persistent operations while maintaining a minimal radar cross-section.
The vessel design uses an angular form described as drawing inspiration from low-profile and stealth vessels in military use, and Glosten is positioned as the lead naval architect for integrating Fleetzero’s propulsion and autonomy technologies into Thoma-Sea built hulls.
How the vessel is positioned for missions
The platform is described as supporting autonomous and remotely operated cargo operations. It is also described as supporting persistent ISR, patrol, and contested logistics missions, with further applicability for electrified harbor craft, tugs, and coastal vessels.
The collaboration’s combined capability is said to have been refined through demonstrations and engineering work with organizations across the maritime sector. The three companies describe the design as functional and aimed at long-duration delivery cycles, rather than retrofit work treated as an afterthought.
Defense-aligned systems requirements and US sourcing targets
The collaboration is intended to address requirements outlined by the Defense Innovation Unit (DIU) and other Department of War stakeholders. It aligns with Department of War, MARAD, and Coast Guard priorities, including the Modular Open Systems Approach (MOSA).
For procurement and compliance, the platform is described as intended to improve operator safety and to meet domestic-content, Jones Act, and Buy American compliance needs for federal customers.
Leviathan Battery claims and the autonomy approach
Fleetzero states its autonomy strategy began with improving the propulsion system as an enabler for eliminating maintenance required while operating autonomously, and it describes diesel-electric propulsion with the Leviathan Battery System as unlocking long-duration autonomy missions.
On performance characteristics, Fleetzero describes Leviathan Battery Systems as providing minimal noise and heat signature, engineering out unnecessary parts, and typically delivering double the energy density compared to other maritime battery systems. Fleetzero says the higher energy density reduces the total bill of materials to manufacture at scale and that its systems dramatically cut operating expenses over the vessel’s lifespan while enhancing reliability and survivability in contested waters.
Industry track record behind the shipyard and architecture roles
Thoma-Sea Marine Constructors, founded in 1989 and based in Houma, Louisiana, operates new construction yards in coastal Louisiana. It was selected by the U.S. Navy’s Naval Sea Systems Command to design and build the NOAA Oceanographer-class research vessels, which the source describes as a $178 million contract, and Thoma-Sea has delivered Navy-administered Foreign Military Sales vessels for allied customers.
Glosten brings more than six decades of naval architecture and marine engineering experience, with a portfolio described as spanning research vessels, commercial cargo ships, and government platforms. Its role in the collaboration is described around defining capabilities including low radar cross-section, silent transit, beach approach angles, and autonomous self-withdrawals.
Glosten CEO calls the design ‘autonomy-native’
Morgan Fanberg, CEO of Glosten, said that bringing autonomy and electrification together at the vessel-design level is where the collaboration creates real value. Fanberg said the companies are designing vessels that are autonomy-native from the keel up rather than retrofitted as an afterthought, describing the design as functional, low-signature, and built for decades of deliveries in the years ahead.
Fleetzero’s funding momentum behind the build
The announced partnership followed a period of significant momentum for Fleetzero, including closing a $43 million Series A funding round in 2025. The source says Fleetzero is backed by investors including 8090 Industries, Y Combinator, Founders Fund, Obvious Ventures, Maersk Growth, and MOL Plus.
Fleetzero says the investment supports continued growth and advanced research and development at its Houston headquarters and backs expanded partnerships, including the collaboration with Thoma-Sea and Glosten to bring next-generation electric autonomous vessel capabilities to market faster.