Great Lakes Dredge & Dock has contracted Ulstein Design & Solutions to design the first US flagged, Jones Act compliant inclined fallpipe vessel for subsea rock installation. The vessel is critical in building the future of the US offshore wind industry, including establishing a US based rock supply chain network.
‘We are extremely proud that Great Lakes Dredge & Dock Co. LLC (GLDD) has entrusted us to develop their new asset,’ says Edwin van Leeuwen, managing director at Ulstein’s Dutch design office. ‘We much enjoyed the cooperation with the GLDD team in developing the concept over the last couple of months, even though we never met physically due to the Covid-19 travel restrictions. Our team is eager to continue the further development of the vessel with GLDD.’
The vessel will primarily serve the growing needs in US offshore wind, installing protective layers of rock at offshore wind turbine foundations by means of an inclined fall pipe system. Furthermore, its large and strong aft deck area makes the vessel a highly flexible asset enabling specialised subsea operations.
Blended design method
‘At the start of the design, we applied our newly developed “Blended Design” method, enabling GLDD to co-evolve their business case with the ship concept. This resulted in significant gains in economic performance, at the same time reducing fuel consumption and emissions, by optimising vessel main dimensions, speed and dynamic positioning capability,’ explains Ko Stroo, Ulstein’s lead naval architect and project manager. ‘Our design for this US Coast Guard compliant vessel is strongly focused on Jones Act compliant shipbuilding in the USA and ease of construction.’
The basic design will be developed by Ulstein’s Dutch design office, with strong engineering contributions from its sister offices in Norway and Poland.
Picture (top): The rock installation vessel will be installing protective layers of rock at offshore wind turbine foundations by means of an inclined fall pipe system.