PEC & Level 3

ETA managed the installation of two cross channel cables for Alcatel Submarine Networks (ASN) on behalf of CTC Marine Projects. The Pan European Crossing (PEC) is part of Global Crossing's network. The 'Tangerine' cable connects the UK with the rest of Level 3's global submarine cable network.

An innovative approach won CTC this challenging project as their first ever cable installation. As a result, the project team had to provide a highly capable lay and burial spread within 12 weeks of contract award.

Several challenges for the satisfactory installation of the cable were identified:

  • Exposed chalk bedrock was present in the approaches to the UK. Existing cable fault records led to a burial target of 1m in the chalk.
  • A significant proportion of the route had stiff clay overlaid by mobile sands of varying thickness. In order to ensure continuing protection under sediment migration, a burial target of 0.6m in to the underlying clay, subject to an overall maximum burial of 2m, was defined.
  • In sandwave sections particular emphasis was placed upon minimising cable residual tension to ensure that the cable was not pulled from deep burial in the sandwave troughs.
  • The cable routes cross numerous in service cables and pipes, and closely parallel the SMW3 cable in the approach to Belgium. Specific procedures had to be developed for ploughing to within 100m of existing systems.
  • The installation scheduled for the late autumn/winter would be subject to the extremes of the Southern North Sea weather.

 

Project Management

Jeremy Hartley, the ETA project manager, ran the project from contract award through to completion. Jeremy managed a combined ETA/CTC team, dealing directly with ASN on technical and commercial matters.

One important factor of the project was the short project deadline which had to be met along with the other project challenges. The close co-operation between ETA and CTC enabled the mobilisation of a complete new cable lay and burial spread to be achieved within 12 weeks of contract signature.

ETA's project team developed the installation methodology and the detailed operational procedures including the 'close proximity' ploughing procedures. On completion of the cable lay the ETA team compiled all as built reports.

Route analysis and the team's experience lead to the choice of a rock ripping plough system which was developed primarily for this project. ETA managed the procurement of this equipment as an integral part of the project.

Equipment Build

The Rockplough has a bollard pull capability of 130 tonnes. The vessel selected to provide the necessary sustained tow force was the M/V Northern Admiral, a UT 741 type DP construction class vessel chartered for the project. The vessel lay spread supplied by ETA included the following:

  • Two cable tanks
  • Cable pathway
  • Stern Chutes
  • Jointing and testing container
  • Integrated cable lay system enabling all system parameters to be monitored at various locations including the vessel bridge

Installation

During the installation phase of the project ETA supplied key offshore personnel including the Offshore Superintendent.

The installation of the PEC and Level 3 projects was carried out over a two and a half month period and was completed on time and within budget. Burial targets were also achieved throughout.


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