Offshore compensated lifting Sneak peek #2
First peaks on how-to safely lift offshore wind turbine components from a heaving deck, out in the open ocean.
After docking to the turbine component (see Sneak Peek #1), the Heave Chief starts to increase tension in the rigging, while it keeps compensating the wave motions over its 3,5m stroke. This can be done quickly (e.g. 1000mT in 1 min) or slowly, depending on what the rest of the equipment requires. Once the pre-tension is sufficiently high, the turbine component can be fast-lifted from deck. All this time, the Heave Chief ensures the component stays on deck, without premature lift-offs. For the final fast-lift, the tool ensures the Dynamic Amplication Factor (DAF) stays well under 1.1
Below is footage of such a fast-lift of a GE Halliade X 13 MW turbine tower section. It’s lifted from the deck of a Barge Master platform which is placed underneath the tower to compensate the roll and pitch motions during the pre-lift phase. The fast-lift has a speed of ~70 cm/sec (42m/min), to make sure it clears the deck (including its guides and bumpers) fast enough, before a next wave could push the deck back up and clash with the bottom of the tower. After the tower was fast lifted, the Heave Chief is locked and the tower is brought on board to start installation of the wind turbine.
