Yamaha Motor Corp. recently unveiled a hydrogen-powered outboard boat engine. The H2 was developed in partnership with Roush CleanTech and Regulator Marine Inc.

The outboard engine uses hydrogen as a fuel source in an internal combustion engine and is a derivative of Yamaha’s XTO Offshore, a 5.6-liter V8 capable of 450-h. However, the H2 engine produces slightly less power, due to hydrogen’s lower energy density.

Unlike hydrogen fuel-cell vehicles, the H2 relies on hydrogen combustion, which Yamaha Marine’s chief of technology, Grant Suzuki, describes as “using gaseous hydrogen as the combustible fuel source, essentially maintaining the mechanism of a conventional reciprocating engine.”

Recreational boats account for only 0.7 percent of transportation-related carbon dioxide emissions in the U.S. and 0.4 percent in Europe. However, the marine industry has a vested interest in preserving clean water and ecosystems, making emission-reduction strategies essential.

“Hydrogen combustion presents a promising solution,” says Suzuki. “The technology doesn’t emit carbon during use, making it a carbon-neutral option for marine propulsion.”

The partnership with Roush CleanTech brought decades of hydrogen systems expertise to the project.

Regulator Marine, a longtime collaborator with Yamaha, provided a modified 26-foot hull to house the large hydrogen storage tanks—a key challenge of hydrogen-powered vehicles. 

“Infrastructure and optimizing the engine for hydrogen are among the chief engineering challenges,” explains Suzuki.

Hydrogen’s energy density offers a potential advantage over battery technologies for marine use, particularly in terms of range and refueling times.

“This is part of [our] multi-technology strategy to mitigate carbon emissions,” Suzuki points out. He says H2 remains in the prototype phase, with further study needed to refine its feasibility, environmental footprint and user experience.

However, as hydrogen combustion technology evolves, Suzuki believes it will become a critical piece of the puzzle in creating sustainable marine technology, balancing performance with environmental responsibility. He claims that the H2 outboard is not just an engineering experiment, but a statement on the future of marine mobility.

“Developing this type of system is critical to reducing the carbon emissions of our products,” claims Suzuki. “[We] share a belief that there is no one-size-fits-all solution for carbon-neutral products, and hydrogen is a formidable contender for the future of cleaner internal combustion engines.

“Internal combustion will continue to be a necessary component in recreational boating,” adds Suzuki. “We’re also advocating publicly for sustainable fuels, hydrogen and other technologies we can deploy to continue to meet customer expectations.”