Optimize positioning of a drilling rig

Scope of Work

Based on the success in 2018, the 40Te Scanmachine was reordered to support the footprint of a drilling rig on two locations. This year, the scope of work included:

  • Rock remedial according to design criteria’s from DNV to fulfill stabilisation in the foundation, avoiding use of additional gravel and minimise seabed disturbance
  • Debris removal
  • Uncovering of pipe (preparation for DWS)
  • Relocation of two pipes that had already been cut and left


UK Sector

Main Spread



Tiltbucket, Rippertooth, Log grapple, Bucket w/ teeth, Chaincutter, Ejector system

Water Depth



18 days



Image Caption: Picture from onshore testing of Log grapple and 2m Tilt bucket

Planning Phase

Project specific challenges were highlighted in the planning phase. Based on the significant volume of mass to be processed, we had learned from the 2018 campaign that the grab setup proved to be more efficient than the traditional ejector setup. This time, to further improve the seabed preparation, a 2.1m levelling bucket with tilt was chosen as the main tool. 

In addition, and on short time notice, the client requested if Scanmudring could come up with a tool that could pick up and relocate pipes from 3” to 20”. Scanmudring got hold of a traditional onshore log grapple which was modified and tested at the Scanmudring facilities.

To deal with the debris and potential hard material, a ripper tooth was also brought offshore.

  • High tide currents
  • Low visibility
  • Lack of ROV support
  • Precise placement of rock dump
  • Minimize disturbance to surrounding area
  • Debris
  • How to maximize efficiency in execution of SOW
Specific Tooling

Scanmachine 40Te with the capacity to mount heavy duty tooling

  • High production as well as high precision on placement of material
  • No need for hose handling
  • Less support from ROV needed
  • Works within the given tolerances of +-200mm
  • Commonly used excavation tools from the onshore excavator partners

Other Projects

Installation of an AC power and optical cables system

Installation of an AC power and optical cables system

Planning PhaseOnce the substation jacket was installed, a rock dumping vessel performed the scour protection around the jacket, but there was still a need for rock installation inside the jacket.Challenges Strong current & Low visibility Precise placement of rock...

Seabed preparation at Heimdal

Seabed preparation at Heimdal

As preparation towards an upcoming by-pass operation, Scanmudring was contracted to make 4 pits under existing pipelines to create access for client’s PRS (CRU) and Force.