ULSTEIN designed subsea rock installation vessel will be America’s first GLDD orders Jones Act compliant rock installation vessel to serve U.S. offshore wind.

Great Lakes Dredge & Dock Co. LLC (GLDD), U.S. leading dredging company, has ordered the first U.S.-flagged and Jones Act compliant subsea rock installation vessel, an ULSTEIN S211 design. Designed by Rotterdam based Ulstein Design & Solutions BV, the first vessel will be constructed by Philly Shipyard and is expected to enter operations by Q4 2024 to serve the U.S. offshore wind market. The contract includes the option for a 2nd vessel.

“World-renowned engineering firm Ulstein Design and Solutions B.V. was commissioned by us to design the vessel using state-of-the-art technology, equipment, and automation”, states Eleni Beyko, Great Lakes Dredge & Dock’s Senior Vice President Offshore Wind. “The design was reviewed and approved by the American Bureau of Shipping (“ABS”) and will be built with best-in-class safety and low emissions standards (LEV, Sustain2).”

To reach the low emission and sustainability goals, the vessel design includes EPA Tier 4 engines, plug-in shore power connection for loading in ports and battery packs for peak-shaving. The vessel is also able to run on biofuel to reduce CO2 footprint and is equipped with active emission control technology to minimise NOx emissions.

In the concept phase the Ulstein Blended Design method was used to enhance cargo efficiency, to boost the GLDD business case, and reduce overall fuel consumption.

“It is a privilege to work together with the GLDD newbuilding team. Their vast experience in U.S. shipbuilding, combined with our expertise of rock installation vessel design, was essential in creating this unique vessel for U.S. offshore wind sector”, says Ko Stroo, lead designer in Ulstein Design & Solutions B.V.

Main dimensions of the vessel are:

Loa                              140.5 m / 461 ft

Lpp                              134.9 m / 442 ft

Beam (moulded)              34.1 m / 112 ft

Depth (main deck)           10.7 m /   35 ft

Draught (operational)            7.0 m /   23 ft

Service speed                                   12 kn

Installed power                       2 x 3,150 kW   2 x 2,250 kW

Propulsion thrusters                     2 x 2,500 kW

Retractable thruster                      2 x 1,200 kW

Tunnel thrusters (fwd)                   2 x    900 kW

Positioning system                       DP 2

Class                                        ABS

Rock hold capacity                       20,000 t

Complement                               45 P