Stainless Steel ROV Garage design
Eadon Consulting completed the detailed structural design calculations and full fabrication drawings on behalf of Forum Energy Technologies for their Garage Type ROV tether management system. This all stainless steel garage is used to deploy Forum Energy Technologies XLX Work Class ROV and is required to operate in severe offshore conditions. The garage underwent successful acceptance and integration testing both in the factory and offshore during sea trials. It is now in operation, withstanding the harsh marine environment it was designed for.
Forum Energy Technologies
Initial design involved ensuring that the garage frame could house the ROV and all of the required TMS equipment while remaining within strict size, weight and weight balance restrictions. To achieve as light and unobtrusive a frame as possible we used high strength 31803 duplex folded sections for the main structural load path and less strong 316L rolled stainless steel sections elsewhere. The decision to use folded sections, rather than fabricated plate girders, was taken to reduce costs and to reduce potential excessive distortion during fabrication of stainless steel plate girders. In addition to ensuring that the frame was structurally adequate during operation, it was also imperative to ensure its integrity in the stowed condition, where it will be subjected to very large horizontal accelerations from the movement of the ship in the most severe marine environments.
The design calculations covered all aspects of the garage’s main structure, connections and secondary items for mounting equipment upon. The 3D model and fabrication drawings were created using Solidworks, and the design was carried out with a combination of beam element analysis models (using STAAD Pro) and hand calculations (using Mathcad).
The calculations were carried out to primarily comply with the requirements of Lloyds Certification of Lifting Appliances in a Marine Environment (CLAME), but also using elements of “BS2573 Rules for the design of cranes”, “BS EN 1993-1-4 Design of Steel Structures – Stainless Steel” and some DNV codes.