The M/S Nukumi, a diesel-electric bulk ship operating in the Gulf of St. Laurence and Great Lakes region since early 2022, was designed with many innovations to enhance safety, efficiency and performance while reducing the vessel’s overall environmental footprint.
Making the ship’s onboard production and consumption of power extremely efficient was one essential design goal. A unique direct-drive propulsion system collaboratively designed by Berg Propulsion and The Switch accomplished this very successfully.
When the ship began operations, it received the IBJ Bulk Ship of the Year award, was recognized as a “Significant Ship of the Year” by the Royal Institute of Naval Architecture, and in 2023 was honored as “Vessel of the Year” at the Marine Propulsion Decarbonisation Awards.
Design goals included:
- High redundancy
- High maneuverability
- Improved propulsion efficiency
- Overall energy efficiency gains of 10–20% over conventional systems
- ~25% fewer GHG emissions and 80% fewer harmful air pollutants than the previous vessel on its route
The ship is performing better than anticipated and is a much more efficient vessel than its predecessors in the segment.
Why has the Nukumi been so successful?
To create the most efficient production and consumption of power onboard, The Switch variable speed permanent magnet (PM) generators and Berg Propulsion’s patented inline electrical PM machine system were mounted in a Twin Fin Skeg design. This inline machine arrangement propels a ship electrically with high efficiency and robustness.
The design’s strength is in how the electric motor integrates with the shaft. The motor has no bearings of its own, relying on the bearings in the shaft line. This eliminates the gearbox and all the inherent alignment and integration issues, significantly improving the reliability of the system. Moreover, a system based on a direct-drive PM machine is extremely simple mechanically and requires minimal maintenance, further lowering the operating expenses.
In addition, permanent magnet motor technology results in high efficiency and low electrical losses and allows a full speed range, torque and pitch, and a much larger propeller can be used because of the system’s extremely high torque capability.
Highly collaborative process
Streamlined design is the result of in-depth collaboration of Berg Propulsion and The Switch from the first days of planning, since the biggest advances in efficiency are made in the conceptual phase. We tailor the direct-drive system for each project and optimize it for each vessel’s specific requirements.
Berg Propulsion and The Switch’s deep expertise in their respective fields – combined with considering the vessel holistically instead of just as a collection of subsystems – generates new synergies.
We evaluate different concepts and present all the pros and cons to our clients. We make recommendations, and then the iterative development process starts, using advanced modelling and simulation techniques until peak efficiency is reached. Our experience allows us to achieve the highest efficiency gains.
Other vessels suited for direct-drive propulsion
The proven effectiveness of the Berg/The Switch direct drive has led to more projects with inline direct-drive machines. The system is particularly good for vessels operating in the medium to high power range, such as:
- Icebreakers
- Offshore vessels
- Ferries
- Naval vessels
- Cargo and bunker ships
Other ships requiring high maneuverability or high redundancy also benefit from electric propulsion.
Why not consider the Berg Propulsion/The Switch direct-drive system for your next ship? Contact us to discuss your project needs.
Business Manager, Berg Propulsion Electrical Integration Business Unit
Mattias Dombrowe
Mattias Dombrowe has over two decades of experience in the maritime industry, spanning various leadership roles in business management, engineering and product development. As Business Manager for the Berg Propulsion Electrical Integration Business unit, he is fully committed to advancing ship propulsion system electrification. He and his team focus on improving performance and safety while carefully balancing investment and technical opportunities. With a strong commitment to innovation and excellence, the team members utilize their vast experience to provide effective solutions and ensure customer success.