Floating Production Systems

Longitude has extensive experience of all types of floating production units including FPOSs, FSOs, FLNG and production barges. We have provided the full scope of marine design engineering services for a number of FPSO and FSO conversions as well as engineering support for a number of floating production units in operation from modelling of marine operations to asset integrity assessment.

Semisubmersible / FPSO / FSO Design

Longitude’s work typically covers all aspects of Naval Architecture, Structural and Marine engineering relating to the FPSO from the bottom of the pancake to the bottom of the hull, all thee way to the seabed.

Our experience covers both new builds and conversions, including shipshape, barges and cylindrical units across all areas of the unit.

  • Concept, PRE-FEED and Detailed Design
  • New Build and Conversion
  • Structural design of the hull, process integration and process module structure
  • Mooring design and analysis (Turret, Spread, STP, CALM)
  • Riser Analysis
  • Design for both benign and harsh environments.
  • Motions, Seakeeping and Greenwater Assessment
  • Stability Assessment
  • Installation Design and Analysis
  • Anchor analysis and design of suction piles
  • Metocean Analysis to set the design basis
  • Commercial assessment of the asset from build to operation.

Structrual Asset Integrity, Life Extension and Re-deployment

Our experience of floating production units extends through the life of the units, providing operations and maintenance support, structural asset integrity assessments and where required life extension. Our engineers are able to accurately assess the effects of fatigue and corrosion on a structure and where required, design strengthening or repairs to allow the unit to continue service.

  • Modelling of existing structures
  • Strength and Fatigue Analysis based on inspected and gauged structures
  • Historic Metocean analysis to allow a comparison of design environment with observed environment since installation
  • Re-calibration of fatigue life based on actual historic environment
  • Interpretation of Structural Monitoring
  • Liaison with certifying authorities
  • Steel renewal plans
  • Mitigations for cracks or corrosion
  • In service repair specification and procedures

Moorings and Risers

A critical component of any floating production unit is the mooring and riser system.   Over the years, Longitude has gained extensive track record with all type of mooring.

  • Mooring design, analysis and specification including fatigue analysis
  • Design of single point moorings (SBM, CALM and SALM)
  • Relocation of FPSO mooring and riser systems
  • Installation Engineering for moorings and risers
  • Integration of internal and external turrets
  • Design of chain stoppers

As well as proving mooring analysis and mooring design, Longitude can provide detailed procedures for the installtion of moorings and risers as well as the tow and hook-up of the unit.

Structural Design and Analysis

  • Finite element analysis of hull global strength using either full ship model with dynamic loading or three hold models
  • Design of topside module supports and pipe racks
  • Structural design and analysis of modules
  • Design of helideck, support structures and walkways
  • Design of Riser porch, offloading platform structure
  • Design of Mooring Chain Stoppers foundations
  • Foundations for QRH, life boat davits and FRC
  • Crane pedestal design and analysis
  • Crane boom rest design and analysis
  • Design of flare tower, including foundations
  • Installation winch layout and foundations design

Key Contacts

Managing Director, Longitude USA


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Oil & Gas Market Lead, Longitude

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Case Studies View All

Longitude Completes Engineering Base Scope on FPSO Conversion

Longitude Engineering has completed its engineering base scope for Yinson’s vessel conversion of an FPSO destined for Brazil, including naval architecture, structural engineering and hydrodynamic analysis. “The FPSO…

FSO “Belokamenka” – FPSO Conversion Engineering

Longitude were contracted by BW Offshore to provide the engineering service (Pre-Sanction Stage) based on BWO’s Singapore office for the conversion of a FSO unit (Floating Production Unit) “Belokamenka”…

John Agyekum Kufuor FPSO Conversion

Longitude were contracted by Yinson Production to undertake structural engineering for the conversion of a VLCC to FPSO for operation in OCTP field, offshore Ghana.