With the US offshore wind market about to take off, naval architects, yards and equipment manufacturers have unveiled a spate of feeder vessel designs for the American market
They are doing so because the Jones Act requires any vessel transporting cargo between US ports to be built and flagged in the US and, for the purposes of the Jones Act, a bottom-founded wind turbine foundation is considered a US port.
The problem is, of course, that although work on the first commercial-scale US project, Vineyard Wind, is due to get underway later in 2021, there are no Jones Act turbine installation vessels, although there will be at least one, when Dominion Energy’s newbuild enters service.
A non-Jones Act wind turbine installation vessel can still install wind turbines of course but cannot transport components from a port to a fixed turbine foundation. Ideally, two or more feeder vessels would be assigned to an installation vessel, to ensure it is regularly supplied. Feeder units may be jack-ups, barges or ships, but whatever the type, they need sufficient deck space and strength to transport increasingly large, heavy wind turbines components. Ideally, they would also be dynamic positioning vessels, for maximum efficiency in transit and while manoeuvring when offshore and in port.
For Vineyard Wind, DEME Offshore US, a business unit of Belgium-based DEME, is teaming up with Foss Maritime to install the wind turbines for the project. Foss has confirmed it will provide Jones Act-compliant feeder units for the project and transport components from Port of New Bedford to one of DEME Offshore’s installation jack-up vessels. Exactly what kind of feeder unit Foss will use and exactly how it will transport and handle wind turbine components is not clear yet, but there may be a clue in DEME’s statement that its method is “Jones Act compliant, driven by high-tech engineering, patented solutions and special adaptions to both companies’ vessels.” That would suggest the solution DEME and Foss are adopting will be a little more sophisticated than a barge and a crane.
Potential solutions abound. In April 2021, Huisman in the Netherlands unveiled a motion-compensated platform designed to provide a stable deck area for lifting operations from a feeder vessel. The platform can integrate into the hold of a vessel and align with the deck in such a way that cargo can be skidded on to it. It uses a combination of passive heave-compensating cylinders and an active hydraulic system.
Another Dutch company, Barge Master, unveiled its ‘BM-Feeder’ platform, based on its BM-T700 motion-compensation system. It also ensures that components remain stable during hook-on and lift-off by an installation vessel and, after lift-off, it reduces the risk of ‘re-impact’ and swinging and heaving motions.
Last but by no means least, Ampelmann and C-Job Naval Architects also joined forces to develop a feeder vessel concept for the US offshore wind market. To maximise workability and allow for safe lifting of components, their feeder vessel has a specially designed motion-compensation system from Ampelmann that is designed for safe lifting operations in sea states of up to 2.5 m Hs. It has a compensator positioned close to the vessel’s centre where it can compensate for motions and allow for operations to continue safely and efficiently in adverse weather conditions. And therein, in a nutshell, lies the need for this kind of equipment.
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