Schottel will supply the propulsion package for Les Alizés, Jan De Nul’s new vessel being built at China Merchants Heavy Industry Shipyard
Les Alizés will be equipped with four type SRP 610 FP rudder propellers, two type SRP 610 R retractable rudder propellers and two type STT 7 FP transverse thrusters to ensure optimal propulsion efficiency and maximum manoeuvrability.
Each of the four electrically driven rudder propellers has an input power of 3,000 kW and a propeller diameter of 3.30 m installed at the stern allowing Les Alizés to achieve a maximum speed of 13 knots.
To ensure precise position-keeping in dynamic positioning mode, the two 3,250-kW retractable rudder propellers and two 2,500-kW transverse thrusters will be installed in the bow of the vessel. The retractable units are fitted with an 8° downwards-tilted propeller shaft to reduce thruster-thruster and thruster-hull interactions and increase propulsion efficiency. The tunnel thrusters are designed to be serviced while the vessel is afloat.
The vessel will be equipped with a state-of-the-art condition monitoring system offering automatic, 24/7 onboard surveillance of the propulsion units even in offline mode. This will prolong its drydocking period from 5 to 7.5 years.
Schottel said the permanent vibration monitoring of the system and automatic trend observation of the monitored data will allow for maintenance based on the thruster’s current condition. This helps to avoid unnecessary part exchanges and downtime.
The 236.8-m by 52-m crane vessel will be equipped with the same emissions control technology found on all other low-emissions vessels in the Jan De Nul fleet and will carry a Cleanship NDO7 label and a Green Passport EU label.
The thrusters will be equipped with Schottel’s proprietary, DNV GL type-approved Leacon sealing system. The system ensures continuous leakage control of the seals and prevents water from entering the gearbox and oil from escaping into the seawater. The system complies with the VGP regulations of the US EPA without using environmentally acceptable lubricants.
The main crane will have lift capacity of 5,000 tonnes, a loading capacity of 61,000 tonnes and deck space of 9,300 m².
Jan De Nul Group offshore director Philippe Hutse said Les Alizés will be able to load out, transport and install multiple units of the largest and heaviest wind turbine foundations. Mr Hutse added “In addition, as a crane vessel that floats, it will be able to install heavier and larger foundations into deeper waters and in more challenging seabed conditions.”
Les Alizés will be used to build offshore windfarms and is scheduled to enter operation in 2022.