Kongsberg Maritime launches S-4L waterjet series for high-speed ferry propulsion

The new Kamewa S-4L waterjet series represents a technical evolution in the automotive data ecosystem of maritime propulsion, merging the design characteristics of the established S3 and S4 platforms. This technology is engineered for large high-speed ferries and naval vessels that require enhanced maneuverability and operational durability. The market debut of the S-4L series occurs via a contract to supply the propulsion system for the Horizon X, a next-generation catamaran under construction at Austal Philippines.

Precision Engineering for Port Agility
The S-4L series is designed to optimize performance across various operating profiles, specifically addressing the high-frequency requirements of the Gotland-mainland Sweden route. The propulsion package for the Horizon X consists of two S160-4L waterjets and two S100-4L booster units. A primary technical advancement in the S-160-4L is the integration of a dual bucket and steering nozzle arrangement.

This configuration improves low-speed control and side-docking precision, which allows for faster turnaround times in port. Furthermore, the dual bucket design is engineered to reduce the erosive effects on harbor infrastructure during sideways docking. The units are constructed from duplex stainless steel to provide the structural strength and corrosion resistance necessary for high-speed maritime applications.

Longevity Meets the Digital Supply Chain
The S-4L series supports the digital supply chain of modern fleet management by offering extended maintenance cycles. The system maintains a mean time between overhaul (MTBO) of 25,000 hours, or approximately five years, for wear parts. This durability is achieved through a mixed-flow pump design, optimized via computational fluid dynamics (CFD) at the Kongsberg Hydrodynamic Research Centre.




On the Horizon X, these waterjets will be integrated into a unique combined-cycle power plant. This system utilizes both gas and steam turbines to drive the waterjets, achieving a projected fuel efficiency of approximately 50%. This configuration significantly exceeds the efficiency benchmarks of traditional marine diesel engines.

Powering the Hydrogen-Ready Fleet
The Horizon X serves as a primary application case for the S-4L series in the transition toward zero-emission maritime transport. The 130-meter vessel is designed with a multi-fuel, hydrogen-ready configuration. It will utilize "green aluminum" in its construction to reduce embodied carbon and is capable of operating on LNG, bio-LNG, methanol, and eventually 100% hydrogen.

When it enters service on the Visby-Nynäshamn and Visby-Oskarshamn routes, the ferry will transport up to 1,500 passengers and 400 vehicles at speeds of 30 knots. The S-4L waterjets provide the necessary thrust to maintain these service speeds while accommodating the vessel's high-efficiency combined-cycle power plant.

Benchmarking the S-4L Evolution
The S-4L series expands the existing Kamewa steel waterjet range, which includes the S3 and S4 series. While the S4 series provides high pump efficiency for vessels operating below 30 knots, the S-4L (available from size 100 and above) specifically targets larger vessels with power requirements ranging from 10,200 kW to 33,000 kW. Compared to previous models, the S-4L offers a more robust dual-bucket steering system and a higher MTBO, positioning it as a benchmark for durability in the high-speed ferry and naval sectors.

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