Water Injection Dredger RIJN
Shipyard Kooiman Zwijndrecht
The RIJN is one of the two newest water injection vessels built by Shipyard Kooiman in Zwijndrecht for dredging company Van Oord.
In order to keep pace with the increasing volume of maritime transport, seaports and waterways must be and remain easily accessible to visiting ships. Maintenance will increase as a result. In this maintenance, water injection dredging is an efficient and energy-efficient method.
Water injection dredging (WID) is a dredging technique in which water is injected just above the bottom with a water injection bar. The fine sediment is loosened and moved ‘naturally’ by the current that prevails on the spot. It is an efficient and environmentally friendly way to keep channels, ports and rivers at depth. Thanks to its high maneuverability, the Rhine can work very close to the banks, quay walls and jetties. The maximum dredge depth is 24 meters.
However, the RIJN and her sister ship the RHÔNE have further developed the same specifications as the previously built MAAS and MERSEY with innovative optimizations based on practical experiences.
During the design, a lot of attention was paid to efficient energy management. The RIJN is equipped with a so-called hybrid energy management system. The power supply is provided by two main generators and two battery packs, the major consumers are the two rudder propellers, one bow thruster, two low pressure jet pumps and two winches to operate the U-shaped injection tube. All electrically powered.
The main AC generators power the DC board by means of two AC-DC converters. From the DC board, the thrusters, pumps and winches are operated and controlled by frequency converters. Because WID dredging is often dependent on the tidal current, it is not possible to dredge continuously. During the quiet periods, the crew sleeps. The batteries are the power supply at that point instead of the generator sets.
Depending on the required WID activities (water injection dredging, mass flowing or power jetting), dredging can be done with one or two generator sets. Based on the required power, the power management system determines whether one or two generators will deliver power, whether or not in combination with the battery pack as a “peak shaver”. Compared to the two previously built WID MAAS and MERSEY, the RIJN has made the necessary adjustments to the software of the power management system in order to reduce energy consumption and associated emissions. The vessels comply with the TIER III regulations for NOx emissions and have the Bureau Veritas notation ULEV (Ultra-Low Emission Vessels). The RIJN is also prepared for the EU STAGE V regulations.
The RIJN is equipped with a Dynamic Positioning (DP) system, which means that dredging can often be carried out in a highly pre-programmed and more efficient manner.
With the RIJN, Shipyard Kooiman has delivered a ship in which the innovations are entirely at the service of the efficient handling of the fuel during the WID work to be carried out. Basically, WID dredging is already environmentally friendly; With the applied power management system, emissions will be minimal.