It has been busy at the beach near Velsen over the last couple of weeks. Contractor NBOS (Boskalis/Orient Cable) was working on installing the sea cables for Tennet’s grid connection to the Hollandse Kust West Beta offshore wind park.
The activities covered installing the shore crossing section of export cable reaching from the dunes, where they will be connected to the onshore power grid, to a connection point at the bottom of the sea. From here on the next 50km of cable is added by the Boskalis cable-laying vessel Ndurance. In order to install these first sections of cable at the shallow coastline, Boskalis’ cable lay barge Giant 7 and trencher the BSSIII were used.
Use of a 300T linear winch for support during cable installation
Bezemer Dordrecht was awarded the scope providing a winch to pull the BSSII from offshore, over a distance of more than 500 meters to the beach. In order to have sufficient pull force their C600 linear winch has been used; a 300-tons continuous linear winch that robustly pulls the cable trencher over the seabed. The winch was provided with a containerized hydraulic power unit, 550 meters of steel wire rope and a spooling winch to collect the wire.
Between the two cable installations, the winch was repositioned. Bezemer provided 2 sets of hold-back rigging, to provide a quick relocation to the second anchor point.
Once the winch pulled the cable trencher to the right position, the trencher was activated and started installing the export cable while the construction vessel GIANT 7 pulled the tool back into the water. When the first cable was successfully installed the whole operation was repeated for the second power cable, resulting in two successful shore crossings.
Winches and offshore wind
Bezemer gets more involved in the development of the offshore wind industries. The winch provider sees an increase in requests to deploy their technology in floating wind installations and the installation of inter array and export cables. Last year, Bezemer successfully completed a project for 6 mooring winches for the South Fork Offshore Wind farm (USA), and they completed the landfall of an export cable for the Iles d’Yeu and Noirmoutier offshore wind farm. In addition, Bezemer has developed an offshore floating wind concept where winches will be used for installing and tensioning moorings for offshore windmills, a low CAPEX and environmentally friendly alternative for the current installation usually completed by powerful anchor handling tugs that are scarce and consume a lot of hydrocarbons.