Longitude routinely carries out projects to support the build and modification of military ships in use in the UK and overseas, and has been responsible for the design of a fleet-wide Fast Rescue Craft (FRC) davit installation. Longitude has designed the FRC installation for five classes of ship, and whilst many aspects are common across the platforms, each installation is specific.

The design of each installation started with a detailed survey to locate the davits and to confirm the baseline sub-structure. Finite Element Analysis tools were used to design the support structure, in many cases to onerous loads and factors of safety. In this case the software package FEMAP was used, along with a library of in-house calculations sheets for undertaking various types of structural analysis. Longitude carries out structural design and analysis in all materials, and these projects were carried out predominantly in steel. One of the installations however involved the design of a composite (glass reinforced plastic, GRP) sub-structure to integrate with that of the vessel, in this case a GRP ex-minehunter.

Detailed design drawings were then generated, supported by extensive work instruction specifications for the work to be carried out, which included including planning for the implications on surrounding spaces and systems. The survey, and subsequent engagement with the shipyard has ensured that each design was practical to build. Support was given both to Classification Society approval and installation, and an as-fitted survey was carried out to confirm that the design intent had been maintained.

To this task Longitude brought knowledge of ship layout design, davit design and the design of supporting ships’ steelwork structures. Longitude carried out a turnkey work package including requirements definition, customer liaison, concept design, detailed design, analysis, manufacturing support, trials and customer acceptance. In taking such an approach the customer can be confident that the design intent is preserved throughout and that a safe and effective system was delivered. All design work was well documented at each stage, providing a high level of support to the build yard. In taking this approach Longitude is able to work directly with overseas shipyards in the same manner as those in the UK.