Jack-Up and Floating Rigs

Longitude has a proven track record of jack up and semi-submersible rig engineering for the upgrade and conversion of drilling, accommodation and production units.

MOPU and Jack-Up Marine Design

Longitude has designed a number of MOPU conversion in which a drilling rig is converted to a production platform.   Our work typically requires all aspects of  naval architecture, structural, and marine system engineering associated with these units.

Our geotechnical engineering services are often required to undertake foundation assessments. This may involve the interpretation of site-specific soils’ data, testing, calculation of foundation stability and resistance to sliding.

Services for MOPUs and rig conversions include the following :-

• MOPU Conversion
• Concept, Pre-FEED, FEED and Detailed Design including cost estimating
• Equipment Foundations
• Rig Foundation Stability Assessment
• Leg and Jack house Fatigue Assessment
• Demolition Engineering
• Marine Operations Manual Updates
• Marine Systems

Engineering Assessments

As well as performing design engineering for rig upgrades, Longitude are often asked to provide engineering assessments of jackup rigs, drill ships and semi submersibles.   These engineering assessments may be relating to in-service operational issues, life extension or an upgrade of a drilling, accommodation or production unit.

Areas of engineering analysis cover the following range of activities across both the oil and gas and renewables markets.

• Intact and Damage Stability Analysis
• Application of regulations (MARPOL, SOLAS etc)
• Site Specific Strength and Fatigue Analysis
• Inclining experiments
• Leg Impact during lowering
• Scour Assessments
• LQ and equipment upgrades
• Global strength analysis for hull, legs and jacking structures
• Analysis of spudcan strength
• Finite Element Analysis of global or local structures
• Design of pipe racks and topside module supports.
• Design of helideck, support structures, fire monitor platforms and walkways.
• Vibration analysis
• Crane Pedestal design and analysis

Rig Activiation

Over recent years, a significant number of rigs have gone into layup, be it cold or warm.   Longitude’s engineers can help owners to assess their units and advice on a range of issues relating to lay-up and stacking.

  • Lay-up/ warm/ cold stack planning and re-activation planning
  • Lay-up /stacking procedures and manuals with recommendations on interim inspections / checks
  • Liaison with insurance interests and / or approval as an independent 3rd party
  • Machinery / equipment protection and preservation measures
  • Advice on maintenance and management during lay-ups
  • Advice on anchoring/mooring adequacy for long term deployment

Marine Systems Engineering

Our marine engineers have worked on MOPU conversions providing designs enabling the unit to work at elevation for long period in a safe manner.   Our engineers are typically involved with the following systems.

  • Design and conversion of marine utility systems, including but not limited to sewage, black, grey portable and drinking water and air systems
  • Ballast design/conversion
  • Design and conversion of bilge, fuel oil, oily water separation, foam, marine HVAC systems
  • Design of fire water system
  • Design of seawater lift system

Key Contacts

Managing Director, Longitude USA


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Oil & Gas Market Lead, Longitude

London, Longitude

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Case Studies View All

MOPU LEG to MAT Re-Assessment, Repair Engineering and Repair Assistance

The MOPU Sepat was converted in 2011 from the mobile self-elevating platform “GPS PRODUCER 1” by Longitude. It was designed, developed and manufactured by Baker Marine Corporation as a…

HALCYON 2 Rig Conversion – MOPU Conversion Engineering

Longitude were contracted by SAJ Tech to provide detailed engineering associated with conversion of Halcyon 2 MODU to a Water Injection Facility Facts and Figures: 3500tons topside’s elevated weight Mat…

H2504 Rig Conversion

Longitude was contracted by Kencana HL Sdn Bhd to provide the detailed engineering associated with the conversion of a MODU to self-elevating accommodation rig. The scope was also inclusive…