Jan De Nul Group has selected Remazel S.p.A. for the delivery of a set of cradles, a skidding system and an upending hinge for its new floating installation vessel Les Alizés to handle and install XXI monopiles. The design of this fully automated monopile installation system is tailor-made for Les Alizés and suitable for challenging weather conditions and harsh sea states.

This mission equipment will allow Les Alizés to safely and efficiently install monopiles in offshore conditions. Les Alizés will use the monopile cradles on its deck to store monopiles. The monopile cradles can automatically adjust their supporting diameter. If required, the cradles can also support the tapered section of the monopile. The skidding system is needed to optimise the use of the deck and will enable Les Alizés to transport the monopiles in between the monopile cradles and the upending hinge.

The upending hinge can accommodate monopiles weighing over 3000 mt. The tub-mounted crane brings the monopile in a vertical position using the upending hinge. Once upended, the monopile is placed into the monopile gripper by the tub-mounted crane.

Automated working method

Les Alizés allows the installation of very large components including jackets exceeding 4500 mt and monopiles weighing over 3000 mt. It is of paramount importance that the installation process for these very large components can be safely executed.

The monopile installation system manipulates the monopiles entirely hands-free and fully automatic. There is no need for rigging or adjusting the supporting diameter of the cradles manually. Moreover, by using a mechanical interface between the skidding system and the upending hinge, the skidding system is able to travel inside the upending line. This feature eliminates the need for a lift of the monopile from the skidding system to the upending hinge by the tub-mounted crane.

This is fully aligned with the no-hands-on-deck philosophy: the automated working method creates a safe environment in which the personnel’s safety is not compromised.

According to Jan De Nul, the construction of Les Alizés is well on track. Recently, an innovative motion-compensated pile gripper was also ordered.

Also read: Keel laid for Jan De Nul’s new floating offshore installation vessel

Picture: Les Alizés is equipped with a crane having a lifting capacity of 5000 tonnes and equally impressive lifting heights.