Longitude was contracted by Gryphon Energy and ROS to provide the full range of naval architecture and structural engineering services for the detailed design of the conversion of a Bethlehem 250 MS jackup drilling unit to a Mobile Offshore Production Unit (MOPU).

Facts and Figures:

  • Bethlehem 250 class Jack-Up Unit
  • Mat Supported
  • Installed adjacent to fixed WHP with bridge link
  • BV Class

Longitude’s Scope of Work

Longitude undertook the full scope of naval architecture and structural design services for the conversion of the Boss 1 Jack-up drilling rig to MOPU. The scope included in-place analysis of the unit including leg strength and fatigue assessments as well as foundation stability assessments.  Transportation engineering was provided for the tow of the unit to site and design engineering provided for all new structures on deck.

The new structures that were designed included leg extensions – which were required in order to be able to jack to the required elevation and a 19m long bridge with A-Frame and winch, allowing the bridge to be transported vertically and lowered into place once the MOPU was installed at final elevation.

Other scope undertaken by Longitude included, the specification of strengthening and repairs required at the mat to leg connection of the unit, cathodic protection of the legs and mat, dropped object assessment and boat impact assessment.   The topsides hull and the jacking system, strength was assessed using Finite Element Analysis (FEA) to demonstrate that the covered vessel has adequate strength.