December 4th 2020

Houlder worked with power cable installation and repair specialists Global Offshore, part of the Global Marine Group, to design and deliver a new deck grillage system for the Q1400 Subsea Trencher system. The aim of this project was to maximise efficiency, reducing mobilisation time and costs for short term trenching projects.

Global Offshore’s current Trencher system comprises of a 47Te SWL A-frame, umbilical winch, snatch limiter, supporting equipment and associated container modules. To integrate the system onto a vessel, it usually requires a set of deck grillages. Currently, grillages are designed specifically for each major Q1400 component and for each charter vessel on which the system is mobilised. Underdeck stiffening is often required, adding significant time and cost to each mobilisation. During mobilisation, all parts are lifted, installed individually and then electrically and hydraulically hooked up, requiring significant vessel time and high utilisation of the vessel’s crane. Global Offshore recognised the need to reduce mobilisation times and by taking the majority of the work off the critical path, efficiency increases.

Houlder responded to the engineering challenge by developing an innovative concept design which minimised the charter vessel time alongside during mobilisation. Additionally, Houlder ensured the system fitted the primary vessel but also the sister ship and any vessel of opportunity, guaranteeing the system was modular and adaptive for multiple projects. The deck grillage system was also designed to be road transportable, stackable for storage, and with reduced seafastening to ensure more efficient mobilisations.

James Smith, Senior Structural Engineer, Houlder, said: “Using our expert knowledge and problem solving experience has been key to providing an efficient solution for Global Offshore. We moved from concept design to fabrication, approval and installation within twelve weeks. The value in a specialist consultative approach is crucial to a successful project and our significant experience in marine and offshore engineering has enabled us to design a solution which meets our clients’ needs – flexible, efficient and reduces cost and time for all parties. The first installation of the new system has taken place and it is great to see the system in action.”

For more information on this project, please click here.