Longitude combines the qualities of a marine engineering consultancy with comprehensive design and planning solutions for infrastructure projects with marine components.

Infrastructure & Construction Sectors

Longitude’s projects, to date, have included the design, fabrication, and shipping of multi-modular equipment for numerous on-shore LNG plants, refineries and mining equipment – even multiple glass roof sections for a major immigration building.

These projects typically involve the offshore shipment of multiple modular structures, potentially over 20-30 shipments per project, by either a combination of tug and flat-top-barge, or by self-propelled vessels through routes between continents.

As well as supporting major modular projects, Longitude are also involved in marine aspects of civil infrastructure works, including the engineering for the design, operation and integrity assessment of jetties, piers, bridges and linkspans.  These projects may involve any aspect of a port or facility from the soils and  foundations, the port structures or the assets using the facility.

Longitude provides the following marine civil engineering and support services to the infrastructure of projects:

  • Derivation of metocean conditions for transportation routes used by multi modular projects
  • Voyage simulation analysis
  • Derivation of module design criteria
  • Stability, motions and strength analysis for transportation
  • Module fatigue analysis
  • In-place analysis of structures
  • Loadout and discharge engineering
  • Heavy lift analysis
  • Preparation of transportation procedures
  • Risk Assessment and HAZID
  • Asset integrity assessment of jetties and mooring dolphins
  • Alongside mooring analysis (Static and Dynamic)
  • Design of infrastructure such as linkspans
  • Manoeuvring simulations
  • Coastal Protection and Seabed mobility

It has become common practice for large onshore construction projects to be built in a modular format at construction yards and then shipped to the project site, rather than stick-built in-situ.

Modules typically include pre-assembled units (PAUs) and pre-assembled racks (PARs) which can range in size from 10 to 2,000 tonnes, with some modules weighing up to 5,000 tonnes – and in some cases, more.   These modules are often shipped from fabrication yards to the construction site on multiple shipments, sometimes as many as 20 shipments in a single project.

Since the beginning of modularization, Longitude has provided major construction and infrastructure companies with early-stage design engineering for module design as well as support for all marine works required by the project.  This support defines a key part of the project execution strategy  – from concept and throughout a project’s execution.

Typical projects start with the derivation of module design criteria for transportation. This requires an assessment of weather conditions for the proposed shipping route. Longitude has access to global wave model data, enabling us to provide metocean analysis for any worldwide location or shipping route, as well as access to voyage simulation analysis. Motions analysis is then undertaken using a range of vessel types that may be suitable for the voyage to derive realistic design criteria. Later in the project, Longitude will assist the client with vessel selection, to ensure that the contracted vessels are capable to safely load, transport and offload the modules.

Other aspects of the project may require fatigue analysis of the module itself; grillage and sea-fastening design and analysis; specification of NDT requirements; load in and out engineering; stability and ballasting assessments; and alongside-mooring design and analysis. Load-in and load-out of the modules may be by lift or roll-on roll-off, using self-propelled multi-axle trailers (SPMT).

Would your organisation benefit from Longitude’s expertise in infrastructure-related marine support services?

Contact our team today to discuss your project.

Key Contacts

Managing Director, Longitude USA


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Oil & Gas Market Lead, Longitude

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