Ocean Kinetics - The Engineering Experts

Marine / Steel plate lost at sea during HVDC cable work

AN INVESTIGATION is underway to determine how a steel plate from a hook used in preparatory work for the Shetland interconnector cable was lost at sea.

The incident happened after damage occurred to one of the grapnel hooks on the MV Sima earlier this week while off the north coast of mainland Scotland.

Plans for the cable taken from a booklet given out by SSEN in 2016.
The route of the planned subsea cable linking Shetland to the Scottish mainland. Image: SSE

A spokesperson for project lead SSEN Transmission said while the steel plate is not considered to present a risk to any marine stakeholders, a notice to mariners was issued.

The steel plate is around 0.4 square metres in size.

The interconnector cable will run between Caithness on mainland Scotland and Weisdale Voe to link Shetland to the national grid once the Viking Energy wind farm goes live in 2024.

Preparatory work has been been taking place ahead of the HVDC transmission link being laid.

The boat in question was on a pre-lay grapnel run to remove any debris from the seabed along the cable route.

A spokesperson for SSEN Transmission told Shetland News:  “On Monday 4 April at around 6.55am, the MV Sima noted some damage to one of the grapnels used when carrying out our pre-lay grapnel run (PLGR) operations associated with the Shetland HVDC project.

“The team onboard carried out an inspection and identified that one of the steel plates, which is approximately 0.4m2, had detached from the grapnel.

“The vessel subsequently carried out a survey of the seabed area but was unable to locate the steel plate.

“While the steel plate is not considered to present a risk to any marine stakeholders, our contractor NKT has issued a ‘notice to mariners’ to advise accordingly.

“An investigation is ongoing in relation to this incident.”