Marine Operations/

Moorings and Risers


Mooring is a common marine operation which may have either a short or long-term requirement. Some vessels such as construction, drilling or accommodation vessels may use their own mooring systems whilst others may need equipment designed or procured specifically for the task. Other vessels such as FPSOs and FSOs will require a permanent mooring system that is fit for the design life of the vessel.

Anchor Patterns & Line Profiles

Longitude provides mooring design and analysis including anchor patterns, line profiles and equipment specifications for variety of temporary and permanent mooring systems, both offshore and alongside a quay. Longitude also provides detailed mooring installation procedures – also for temporary and permanent applications.

Offshore & Onshore Mooring Systems

Longitude’s experience covers complex offshore weather-vaning moorings systems and spread mooring systems in all water depths, utilising chain, wire or synthetic mooring lines, and using a wide range of design codes – including those produced by Classification Societies.

Our analytical capability allows us to choose the most suitable tool for the task at hand, whether static, quasi-static or full-time domain analyses is required. These tools also allow us to simulate multi-vessel operations where one or both vessels or bodies are moored, or to simulate operations with one or more vessel operating using DP (dynamic positioning) rather than a mooring system. These same tools allow us to include the riser systems in the analysis and to undertake a full study of riser and umbilical systems.

Mooring & Operability Analysis

Longitude is often asked to couple mooring analysis with an operability study to determine the weather limitation of an operation or the likely uptime/downtime of the vessel’s ability to work. In the case of accommodation vessels, we may be asked for an assessment of the gangway operability, and in the case of a construction vessel it may be an assessment of the carne operability. Longitude is able to couple the hydrodynamic analysis with metocean data (which may be provided by the client or by Longitude) to establish the likely operability of vessels carrying out a specific operation at a specific location.