The M/S Kostervåg, owned by Koster Marin AB in Sweden, is a notable example of maritime innovation through its conversion from a traditional engine system to a more sustainable electric/battery drive. This case study provided by our colleagues in Trans-Auto AB, one of our sister companies in the Driveline Solutions Group of Axel Johnson International, gives an overview of the vessel’s specifications, the conversion process, and the expected outcomes.

Vessel Specifications

• Vessel Name: M/S Kostervåg
• Owner: Koster Marin AB
• Type: Catamaran
• Model: OMA CAT
• Year Built: 2000
• Builder: Oma båtbyggeri A/S
• Conversion: Swede Ship, 2022
• Length Overall: 30.25 meters
• Beam: 9 meters
• Draft: 1.4 (unspecified units)
• Weight: 82 tons (light displacement), 113 tons (max displacement)
• Engines: 2 x 400 kW Danfoss and Twin Disc MGE-5126 SC
• Engine Power: 800 kW in total, powered by 782kWh LTO batteries and 2 x 100 kW diesel generator AGCO (200 kW)
• Gear Model: Twin Disc MGE-5126 SC
• Gear Ratio: 3,00:1
• Top Speed: 17 knots
• Cruising Speed: 12-14 knots
• Classification Society: SMA
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Introduction

The Kostervåg, a catamaran owned by the company that runs the Koster ferrys, underwent a significant upgrade in 2022. While its transition to an electric/battery drive is noteworthy, an integral aspect of this transformation centres on the Twin Disc MGE-5126 SC gearbox. This case study delves into the gearbox’s specifics and its role in the vessel’s performance and efficiency.

Gearbox Specifications

• Model: Twin Disc MGE-5126 SC
• Gear Ratio: 3,00:1

The choice of the Twin Disc MGE-5126 SC gearbox is pivotal for the vessel’s operation. It is designed to handle the power from the new electric motors efficiently. The gear ratio of 3,00:1 is particularly important, as it ensures the electric motors can operate within their optimal RPM range, thus delivering power smoothly and effectively to the propellers.

Role in Vessel Performance

The gearbox’s ability to manage the torque from the vessel’s dual Danfoss electric motors, each contributing to the combined engine power of 800KW, is crucial. By precisely aligning the engine’s output with the propeller’s requirements, the Twin Disc MGE-5126 SC ensures that the Kostervåg can achieve its top speed of 17 knots and a cruising speed of 12-14 knots without sacrificing efficiency or causing undue stress on the propulsion system.

Impact on Conversion Outcome

The incorporation of the Twin Disc MGE-5126 SC gearbox was a strategic decision that significantly contributed to the success of the vessel’s conversion to hybrid propulsion. The gearbox’s reliability and performance directly impact the vessel’s operational capabilities, allowing for a smooth transition between power sources and contributing to Kostervåg’s overall sustainability goals.

Conclusion

• The Twin Disc MGE-5126 SC gearbox stands out as a critical component in the refit of the Kostervåg catamaran. Its integration exemplifies the attention to detail and commitment to quality necessary to successfully convert from traditional propulsion to an advanced electric/battery system, positioning Koster Marin at the forefront of maritime innovation.

To find out more about hybridisation and the Twin Disc MGE Marine Transmission, speak to a member of our team.