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DEME Offshore US contracts Seaqualize

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DEME Offshore US has signed a contract with Dutch heave compensation specialist, Seaqualize, for first offshore wind feeder barge operations in the USA. DEME Offshore US will deploy the newly developed offshore lifting device, the Heave Chief 1100, on the first commercial scale wind farm installation project in the USA, Vineyard Wind, to transfer delicate wind turbine components to and from heaving supply vessels. The HC1100 is currently the largest active heave compensator in the world. As a Balanced Heave Compensator (BHC), it can compensate a vessel’s heave motions and safely quick-lift loads up to 1100mT, although being battery powered.

DEME Offshore, one of the market leaders in offshore wind installations, is the first contractor that will embark on such an operation, by transporting and installing 62 wind turbine generators for the Vineyard Wind 1 project, the first commercial scale offshore wind installation in the United States. Each turbine will be transported in components from the supply harbor to DEME’s installation vessel Sea Installer. DEME Offshore US has contracted the HC1100 to ensure the components can be safely lifted from the heaving supply barges, and thus continue working in challenging weather conditions.

“We contracted Seaqualize to de-risk the Vineyard Wind project: their solution is a novel, but realistic method to safely transfer the delicate components, minimizing the risk of damage and delays. We think this is how Feeder Barge operations should be done going forward”Glenn Carton, Project Director Vineyard Wind, DEME 

World’s largest active heave compensator

Since December 2019, Seaqualize develops inline Balanced Heave Compensators, specifically for heavy lift, in-air active load control. Together with Van Oord Offshore Wind a prototype for 600mT was successfully tested in November 2021. The HC1100 is based on this prototype and will be the world’s largest and most sophisticated active heave compensator. It is scheduled for delivery in March 2023. 

The HC1100 has an improved design to better serve the offshore wind market. It has an increased load-capacity of 1100mT (equivalent to nearly 7 jumbo jets), required to balance turbine components of the 15MW generation. It can reach higher quick-lift speeds and has a longer stroke to handle the larger motions of smaller supply vessels. It also offers a single lift point for operational efficiency. The new design further minimizes dynamic load fluctuations impacting the crane and offers passive safety procedures. In addition, Seaqualize’s in-house developed ‘follow-mode’ allows the full load to match the movements of the target vessel. If required, quick-lift operations are fully reversible. Installation for first US commercial scale offshore wind farm ‘Vineyard Wind’ expected to start in June 2023

More projects to follow

As many more wind installation projects will follow Vineyard Wind, various offshore installation contractors are currently investigating how to include the Heave Chief into their feeder-barge setup. Seaqualize expects to announce an additional contract before the end of the year, cementing Balanced Heave Compensation as the way to go for safe and efficient offshore feeder lifts. Alongside the HC1100, the company’s first full-scale BHC prototype is currently being upgraded for working loads up to 750mT.

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