Boulder Relocation for Vineyard Wind 1 – Nantucket Sound

Project details


Massachusetts, USA


Subsea Mechanical Grapple “AuxRov”

Key Deliverables

Locate, inspect, and relocate subsea targets identified as potential hazards to the subsea export cable installation route.

Project Challenge

A project requiring a quick turnaround supporting laying operations in the first US offshore utility-scale windfarm: Vineyard Wind 1.



Sulmara was contracted to locate, inspect, and relocate subsea targets identified as potential hazards along the Vineyard Wind 1 (VW1) Offshore Export Cable Corridor (OECC) connecting the 800-megawatt VW1 Wind Turbine Area (WTA) to the shoreside landing at Covell’s Beach, Massachusetts.

Sulmara initiated the project in four weeks from the contract signature to the client kick-off meeting.  A vessel deploying a mechanical subsea grapple through the A-frame at the vessel’s stern was deployed to scan and remove any identified objects.  A high current regime, inaccurate provided water depths and shifting sands in the Muskeget Channel made this a continuously challenging environment within which to work.

Before departing New Bedford, the vessel embarked representatives from Local Labor 385 & Local Divers 56 who sailed as trained observers keeping a watchful eye for cetaceans and turtles during daylight hours.



A Covid-19 outbreak during mobilization revealed the vessel owner did not have an infectious disease outbreak management plan and was looking to Sulmara for guidance. The Sulmara project team down-manned the vessel, provided a cleaning service to disinfect the vessel accommodation and implemented a strict regimen of monitoring & testing. After the initial outbreak and localized spread during mobilization, Covid-19 had no further impact to the project.



The vessel was offshore in the Nantucket Sound and Muskeget Channel for nine days deploying the mechanical subsea grapple and successfully relocated fifty eight objects in total ranging from boulders to fishing debris.

A flexible partner that takes the initiative is key to the success of any project, especially in the challenging offshore environment.