Subsea Cable Engineering & Consultancy
ABL Group provides market-leading consultancy services for subsea cable risk, installation studies and vessel mobilisation. Our involvement in the renewables and subsea interconnector goes back over a decade of providing engineering and design support for asset owners and cable installation contractors.
We provide the services our customers require to fulfil their mission of designing cable routes and understanding risk, installation, vessel mobilisation and protecting cables, and maintaining and repairing cables for their offshore wind projects and subsea interconnectors.
Whether the customers are developers constructing the transmission assets, EPCI companies supplying and installing or OFTOs reviewing for transactions or maintaining the asset, ABL Group provides the expert support which is required.
Subsea cable routing
We ensure the effective protection of the cable system throughout its design life with our in-house team of cable experts and geotechnical specialists. Including review information such as SI, bathymetry, seabed mobility and other hazards to prepare cable burial risk assessments (CBRA) and assess the expected performance of available installation tools.
We also bring a deep understanding of vessel movements and capabilities, ensuring that cable routing is sympathetic to vessel manoeuvrability. We also have first-hand experience of the issues surrounding damage to cables through our warranty services and in using that knowledge, we are able to mitigate against potential risks in the early stages of a project.
Subsea cables services
- Routing
- Review of site data to ensure optimal routing of cable lines with respect to practical and economic considerations
- Burial Risk Analysis
- Anthropogenic and natural hazard determination and assessment using enhanced CBRA methodology
- Burial Assessment
- Tool selection and achievability based on house experience
- Cable protection
- Installation
- Ongoing support to ensure continued protection of cables, including post-lay analysis and review of protection measures and cable-soil interaction studies
Our cable risk assessments are based upon the Cable Burial Risk Assessment Methodology, Guidance for the Preparation of Cable Burial Depth of Lowering Specification, CTC835, February 2015. However, Longitude understands the limitations of this guidance, and we are active in exploring improvements to the assessment of threats to the cable.
Submarine Cable Installation Services
Our operational-focussed submarine cable installation services include skidding moorings, cable lay and pull, analysed in simulations using Orcaflex – the industry standard software applied to these operations.
Longitude has also developed its own tool for automating the pre- and post-processing of cable installation analyses, allowing us to handle an increasing number of environmental cases, as requested by the Marine Warranty Surveyors (MWS).
Hydrodynamic Analysis, Shipyard Support, Project Management
Our capabilities cover a wide range of disciplines, from hydrodynamic and structural design and analysis through to concept deck layouts and shipyard support and project management.
Such services include:
- Concept design and design specification for cable lay vessel conversions, including stability, powering and motions response calculations, machinery selection and DP (dynamic positioning) system layout, basic design, shipyard selection, detailed design review and stability and DP2 FMEA documentation
- Hydrodynamic analyses for cable lay and pull-in operations ranging from vessel skidding and survival mooring analyses to transportation and shallow water site-specific seakeeping RAOs analysis
- Cable lay analyses, including quasi-static and full dynamic analyses
- Foreshore pull-in analyses
- 1st and 2nd end WTG/OSS cable pull-in analyses
- Seabed stability analyses
