NKT – Noss Head, Scotland

Rock cable berm for protection of power cable in the North Sea 

A new HVDC interconnector cable was being installed to link the Shetland Islands with Scotland, with NKT as the cable designer, manufacturer, and installation contractor.

In the landfall near Scotland, the cable could not be trenched into the seabed due to the presence of rock. Instead, NKT secured the cable by installing a rock berm on top of the cable.

Rohde Nielsen was awarded a contract for rock berm design verification and rock procurement, delivery, installation, and documentation. The rock berm consisted of a two-layer structure comprising a filter layer of 45-125mm rock in standard density (2650kg/m3) and an armour layer of 5-40kg or 60-300kg in high density rock (3100kg/m3).

The combined berm structure extended 1100m, comprised 22,000 tons of rock, and was installed at a depth of 23-30m in the northern part of Scotland facing the North Sea. Rohde Nielsen engaged a consultant to verify and document the design and hydraulic stability of the rock berm.

  • Location: Near Noss Head, Scotland (GBR)
  • Scope: 22,000 tons of rock
  • Client: NKT
  • Year: 2022

The fleet that made it possible

  • Grane R
Hopper capacity
Length overall
Draught loaded
Draught unloaded
Dredging/Installation depth
up to 100.00m

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