For the past two years, MARIN has supported Dutch startup Tetrahedron to design, verify and improve the performance of an innovative tag line system applied on its novel crane. The Tetrahedron crane was winner of the 2020 Offshore Wind Innovators Award.

The Tetrahedron crane aims at increasing the lifting height of cranes on jack-up vessels for the installation and maintenance of wind turbines. This enables the use of vessels that otherwise would become obsolete for handling modern and next generation wind turbines.

To achieve this, the crane fits on the same base of that of the vessel’s existing crane while the pivot point is moved from the bottom to the top.

Also read: VIDEO: How Rotterdam-designed super crane reaches higher than others

Diamond tag line

A well-performing tag line system in various environmental conditions is a key requirement for efficient offshore wind installation and maintenance operations. The Diamond tag line system is developed as a simple system for effectively constraining load motions in a wide range of blade positions and orientations.

The video below (20x FF) shows a fast-time simulation of a 12MW+ wind turbine blade lifting operation in strong (6bft) wind conditions. While operator actions are prescribed to manoeuvre the crane, the Diamond tag line system controller actively mitigates the tilt and yaw disturbances of the blade, respecting tagline load limitations.

According to MARIN, final validation of the numerical results is envisaged for 2024, after construction of the Tetrahedron crane full-scale prototype.

This project was supported by the Dutch Ministry of Economic Affairs, with a subsidy from Topsector Energie.

Picture: Tetrahedron’s 130-metre-tall prototype crane (by Tetrahedron).

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