Ulstein to design Jones Act rock installation vessel

Ulstein Design & Solutions BV has won a contract from Great Lakes Dredge & Dock Co. LLC (GLDD) to design the first Jones Act-compliant subsea rock installation vessel for operation in United States waters. Such vessels are considered essential for the construction of offshore wind farms there, a sector that is still at an early stage of development, but which is now expected to grow rapidly over the next decade and beyond.

The vessel, which under Jones Act requirements will have to fly the American flag, has been designed with straightforward construction in a United States shipyard in mind. On commissioning, the ship will install protective layers of rock around the foundations of offshore wind turbines using an inclined fall-pipe system. The design incorporates a large after deck which will add to the vessel’s versatility and provide scope for GLDD to undertake other specialised subsea operations. 

Ulstein’s lead naval architect and project manager, Ko Stroo, commented: “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.”

The collaborative work between the two companies required by the blended design process was carried out remotely, without a physical meeting, owing to Covid-19 restrictions.