The boat, which is 14.36 meters long and 4.36 meters wide, was built as part of a proof-of-concept (PoC) project. The project aims to investigate how hydrogen can be used for power generation, electric propulsion, and other onboard energy applications. The project partners hope to gain practical experience with technologies for future maritime applications.
Cefmof was founded in 2024 by the City of Jyväskylä, the Toyota Mobility Foundation, and the Toyota GAZOO Racing World Rally Team.
HARMO electric propulsion system on the hydrogen-powered sauna boat. © Central Finland Mobility Foundation / Yamaha Motor Company Ltd.
Hydrogen powers the drive system and the sauna
Yamaha Motor has provided its HARMO electric propulsion and control system for the hydrogen-powered sauna boat. Four of these units are designed to power the boat. They would be powered by electricity from ahydrogen fuel cell. In addition, the hydrogen would be used to power other onboard electronics, heat the sauna, and operate the hydrogen grill.
The energy system consists of replaceable hydrogen cartridges, a fuel cell system, a battery system, and an electric drive. Hydrogen cartridges are portable storage units forH2. According to Cefmof, the cartridges for the hydrogen-powered sauna boat can be replaced at the harbor.
A hydrogen fill-up of about one kilogram allows for a boat trip lasting about two hours. During that time, a maximum of 12 people can be on deck.
Project Tests Hydrogen Systems Under Real-World Conditions
Haruka Arai, managing director at Cefmof, explained that the hydrogen-powered sauna boat enables the development of an integrated system in which hydrogen storage, power generation, electric propulsion, and other hydrogen-based energy applications work together in a real-world environment. According to Arai , such projects are not about developing a single vessel, but rather about building knowledge.
A view inside the hydrogen-powered sauna boat. © Central Finland Mobility Foundation / Yamaha Motor Company Ltd.
In the current phase of the PoC project, therefore, the focus is not on developing a commercial product. Rather, the goal is to gain practical experience that will help further develop hydrogen technologies.
Gas sensors are designed to detect leaks
According to Cefmof, safety played a central role in the boat’s development. Gas sensors are designed to continuously monitor the hydrogen concentration so that the hydrogen supply can be automatically shut off if a leak is detected. Continuous ventilation and other technical safety measures are intended to prevent hydrogen from accumulating in enclosed spaces.
According to the company, the first public demonstrations of the hydrogen-powered sauna boat took place during the 2026 Rally Finland. The rally is a motorsports competition held in Jyväskylä. In 2026, the event took place from July 30 to August 2.
