Shipowner Jan De Nul has called for clarity in the offshore wind turbine market when it comes to ordering hugely expensive ships.

Last year, the Luxembourg-based company agreed to pay about €300m ($335m) for a new wind turbine installation vessel (WTIV).

This is the giant 61,000-dwt Lez Alizes, which is as tall as the Eiffel Tower.

The vessel is being constructed at China Merchants Heavy Industry (CMHI) for handover in 2022.