First steel has been cut for Jan De Nul’s new crane vessel Les Alizés. With its 5000-tonne crane, the floating installation vessel will mainly be used for wind farm construction, but it is also suitable for decommissioning offshore oil and gas platforms.

It took thirteen months of preparation, designing and planning, to get to the kick off of construction. The ship is being built at China Merchants Heavy Industry (Jiangsu) Co., Ltd. in China.

Thanks to its dimensions and impressive lifting and loading capacities, Les Alizés will be able to load out, transport and install multiple units of the largest and heaviest wind turbine foundations. 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.

Floating installation vessel

Les Alizés is specifically designed for loading, transporting, lifting and installing offshore wind turbine foundations. The main features are a main crane of 5000 tonnes to be built by Huisman, a deck loading capacity of 61,000 tonnes and a deck space of 9300 m2. With these characteristics, the vessel can easily transport the heavier future foundations, several in one trip, to the offshore installation site, with direct benefits in planning, fuel consumption and emissions reduction.

Unlike Jan De Nul’s other offshore installation vessel under construction, the Voltaire, Les Alizés does not have four legs to lift itself above the sea surface. It is a crane vessel for floating installation, which means that the vessel is not dependent on the water depths and the seabed conditions. Les Alizés is equipped with a high-performance DP2 system.

Stage V and energy storage

The ship will be equipped with an exhaust gas filtering technology that complies with the strict European Euro Stage V guidelines for emissions on land and inland waterways. This highly advanced dual exhaust filter system removes up to 99 per cent of nanoparticles from emissions using a diesel particulate filter (DPF) followed by a selective catalytic reduction system (SCR) for NOx removal.

Additionally, the crane vessel will be fitted with an Energy Storage System (ESS), forming a hybrid setup together with the main diesel engines. This ESS will compensate power peaks on the main engines and recover energy from the heavy lift crane, resulting in optimised engine operation and less fuel consumption and emissions.

Les Alizés will have a Cleanship NDO7 and Green Passport EU label. The Cleanship label confirms that the vessel checks and minimises the waste water and all other residual waste. The Green Passport means that all materials and hazardous substances are mapped out during the construction phase, in order to facilitate recycling of the vessel when decommissioned. Both certificates are issued by a specialised external agency.

Vessel particulars

  • Flag: Luxembourg
  • Length overall: 236.8 m
  • Breadth: 52 m
  • Maximum draught: 10.5 m
  • Moulded depth: 16 m
  • DWT: 61,000 t

Crane system

  • Crane make: Huisman
  • Max. lifting capacity main block: 5000 t at 36 m
  • Max. lifting capacity auxiliary block: 1500 t at 46 m
  • Lift above deck main block: 125 m at 21.5 m
  • Lift above deck main block auxiliary block: 167 m at 29.5 m
  • Depth range auxiliary block: 600 t at 100 m water depth, 380 t at 440 m water depth
  • Cargo deck: 9300 m2
  • Max. deck load: 30 t/m2

Machinery – propulsion

  • Main gen. sets: diesel engines MAN 6 x 7,200 kW, 3 x 6,600 V, 60 Hz
  • Emergency gen. set: 600 kW
  • Harbour gen. set: 1700 kW
  • Emissions: ULEv (Ultra Low Emission vessel), IMO Tier III Euro Stage V
  • Main propulsion: 4 x azimuth thrusters 3000 kW
  • Retractable thrusters: 2 x 3250 kW
  • Bow thrusters: 2 x 2600 kW
  • Max. speed: 13 kn
  • Accommodation: 120 single, 15 double cabins