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Fleetzero, Houston, is partnering with naval architecture firm Glosten, Seattle, to design what is expected to become the world’s longest-range, hybrid-electric vessel.
The initiative was announced by Glosten on Aug. 15 and involves the retrofit of the AET Innovator, a 185' lightering support vessel originally built in 2011 by Leevac Industries, Jennings, La., and currently operated by a U.S. arm of Singapore-headquartered shipping company AET.
Fleetzero, a developer of modular electric propulsion systems, is spearheading the effort to transform the diesel-powered AET Innovator into a plug-in hybrid-electric vessel. Once the conversion is complete, the vessel will operate primarily on battery power for low-emission, long-distance operations.
“This vessel will be a major milestone — not just for us, but for the entire industry,” Steven Henderson, CEO of Fleetzero, said in a statement. “Partnering with Glosten allows us to showcase how our propulsion technology can enable economical, cleaner, and more efficient operations, while pushing the boundaries of what’s possible in shipping.”
The conversion of the AET Innovator will involve a complete overhaul of its propulsion system. The current diesel configuration, which includes two CAT 3512C engines delivering a combined 2,088 kW, will be replaced with two 800-kW electric motors powered by over 10 MWh of Fleetzero’s Leviathan battery systems, a Glosten spokesperson told WorkBoat. This new setup will enable the vessel to travel more than 150 nautical miles at an 8-knot cruising speed under battery power alone.
Additional modifications include the removal of the ship’s AC switchboards and diesel generators, and the conversion of two fuel tanks into battery rooms. The retrofit will also install DC link cabinets, new diesel generators (for hybrid operation), transformers, and upgraded shore power connectivity, along with supporting auxiliary systems and fire suppression, the Glosten spokesperson said.
Despite the change in propulsion power, the vessel's performance is expected to remain operationally consistent, with only a minor reduction in maximum speed from 12.8 knots to 12.2 knots in calm waters, according to Glosten, which noted that maneuverability is projected to improve due to the electric motors’ high torque and faster response times compared to diesel engines.
“We’re excited to support Fleetzero in transforming this vessel,” Morgan Fanberg, CEO and president of Glosten, said in a statement. “It’s a bold move toward the next generation of marine technology, and exactly the kind of advancement we’re proud to support.”
While shipyard selection for the retrofit is still underway, detailed design and engineering work is progressing, with construction expected to begin in mid-2026.
