Customer: Kooiman Marine Group, NL
Related services: Ship resistance & powering prediction, CFD simulation, adapted propeller design & supply
Scope of work:
- 3D model of the hull
- Hull analysis by CFD tools
- Nominal wake calculation
- Self-propulsion computation
- Propeller geometry design, adapted to vessel operational profile
- Supply of propellers compatible with existing shafts
Vessel Zwerver I is a shallow-draft DP2 multipurpose support vessel converted by Van Stee Offshore and Kooiman Marine. VICUSdt delivered ducted propellers for multipurpose vessels by conducting CFD-based hull resistance analysis, wake calculation, and bespoke propeller geometry tailored to bollard-pull performance. The retrofitted Zwerver I operates with eight thrusters—each 2000 mm 5-blade fixed-pitch propeller in Kort nozzles—achieving exceptional thrust and control in configurations up to 69 t bollard pull. This demonstrates how ducted propeller design can enhance efficiency and maneuverability in shallow-draft workboats.
Advanced Propulsion with Ducted Propellers
Within VICUSdt’s ducted propeller design process, we started by creating a 3D hull model and performing CFD resistance and wake-flow simulations. The design was optimized for bollard-pull conditions, using nozzle-encased propellers with adjusted blade sections, rake, and pitch to minimize cavitation and maximize thrust. The 5-bladed, 2 m diameter propellers were installed on new shaft lines driven by 940 kW engines—resulting in superior control and power readiness.
At operational speeds of 6–9 kn, the ducted configurations maintained efficiency, while the Kort nozzles improved thrust in shallow water by concentrating inflow and reducing tip vortices. The result: Zwerver I demonstrated remarkable bollard pull (up to 69 t) and reliable performance across DP and towing operations—ideal for multipurpose service vessels in constrained draft environments.
Operational Benefits and Strategic Impact
The re-engineered propulsion system with ducted propellers for multipurpose vessels had tangible benefits during her DP trials:
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Increased bollard pull and traction in shallow waters. Kort nozzles boosted thrust by focusing flow and reducing energy loss.
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Cavitation control under full load: nozzle shrouding allowed higher efficiency at bollard and low-speed operation.
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Compact installation: Short ducted propellers maintained vessel draft, ideal for tidal operations and port logistics.
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Versatile maneuvering: Flow alignment from nozzle-enhanced propellers improved response during DP and towing configurations, vital for offshore support tasks.
Van Stee Offshore reported astonishing performance post-conversion. VICUSdt’s engineering ensured that propulsive upgrades delivered real operational value—transforming Zwerver I into a high-performing multipurpose vessel with enhanced efficiency, responsiveness, and seabed-friendly draft.
For further details of this vessel, you can watch the video.
