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History

In the early years of Fairlead Maritime we specialised in numerical analyses like spectral fatigue, hydrodynamics and fracture mechanics assessments for the oil and gas industry. Our work soon became more varied and we now cover most aspects of the floating world structural design, collision analysis, semi subs, jackups, mooring analysis, lifting gear, model testing, concrete fixings, NDE. We still work in oil and gas but its now more than 50% of our businesses is in offshore renewable energy, coastal structures and shipping..

Clients

ALLSEAS
BP
MAERSK
MPI
MTL
PROSAFE
SUNCOR
TALISMAN
VAN OORD
ZYBA (CCELL)

The early days

2011 Allseas : Pioneering Spirit

In 2011 Fairlead’s first project was to check the fatigue resistance of fatigue critical details of the largest ship in the world! Pioneering Spirit is 382m LOA, 124m beam and at deepest draught the displacement is 1 million tonnes. It can lift 40,000 tonne topsides and 25000 tonne jackets and is also the worlds largest pipe-layer.

This was the start of a good relationship with Allseas and over the next few years , after identifying the fatigue critical areas we designed many fatigue critical parts of the hull, including the connections of the twin bows to the main hull, the scarphing brackets which connect the super structure to the main deck, the ends of the lifting rails. This was a great project to contribute to; we were honoured to be chosen to solve such difficult fatigue design challenges in partnership with Allseas, Lloyds Register and The Welding Institute.

Our work with Pioneering Spirit continued over the next few years. We carried out design verification of the 25,000 tonne lift shear legs at the aft of the vessel , the 48,000 lift at the bows and various design modifications, strength, hydrodynamics, fatigue and fracture mechanics assessments.

We also assisted Allseas with the design of the connections of the shear legs to the main deck and other aspects of the lifting gear

https://allseas.com/equipment/pioneering-spirit/

2012 Marine Technical Limits : FPSOs in the North Sea

In 2012 we carried out the first of many successful close collaborations with the excellent MTL, mainly life extension studies of FPSOs in the North Sea and North Atlantic. These vessels operate in a harsh environment for many years and it is always a challenge to safely keep them operating whilst repairs are carried out at sea, we like a challenge and continued with other FPSOs in the following years. Since the FPSOs operate in harsh environments in the North Atlantic and North Sea we used some advanced spectral fatigue and fracture mechanics to reduce downtime and to be sure that the repairs and.or operational changes would keep the vessels operating safely. The end clients were Maersk, Talisman, Suncor.

Spreading our wings building relationships

2012 MPI: Jackups, renewables and wind turbines

In 2012 we carried out our first site specific assessment for MPI Adventure, which at the time was the largest self elevating wind turbine installation vessel in the world, it has a 1000 tonne crane at the aft end whihc is uses to install turbines, piles, topsides and other parts of offshore windfarms. It has six seventy metre long legs to jack it up above the crest of the waves. This was the start of many enjoyable and productive years working with MPI (now part of Van Oord. Our work encompasses site specific assessments, punch through risk assessments, structural modifications, repairs, fatigue design, technical investigations, model testing, and problem solving. Over the years we developed our own in-house software to carry out ISO 19905 time domain stochastic analyses of the loads on spudcan foundations, to calculate sea fastening loads and to calculate air gaps whilst transporting components offshore.

2013: PROSAFE: Semi Submersibles

We started working with PROSAFE on life extension of a GVA3000 semi-submersible and a collision assessment in the Grane field of the North Sea. PROSAFE were a great team to work with and over the years we carried out more than eighty projects for them including fatigue assessments, collision assessments, full scale model overload tests of windows, structural modifications, new build design verification, predicting slamming loads, deriving operational limits and covered many fields in the North Sea.

2013: BP : design specifications for Tankers

We helped BP to update their design specifications for new build tankers to reduce the risk of green seas on the deck. We carried out hydrodynamic calculations and statistical analysis and derived new limits with input from MARIN

Timeline 2011 till 2020

DESCRIPTION	YEAR	COMMENTS	Vessel Type
Quick fatigue assessment of new build heavy lift vessel	2011	Successfully Completed “Quick” spectral fatigue (FDA3) in two weeks to aid with steel order design freeze. Identified details with low fatigue lives and delivered recommendations for design modifications. Subsequently the findings were confirmed by analysis from Class and yard	Heavy lift
Fatigue assessment (FDA Level 3) of hull structure of heavy lift vessel	2011	Design wave screening and spectral fatigue (FDA3)+ recommendations for design improvements	Heavy lift
Appraise stage analysis of cracks in COT of FPSO for life extension decisions	2011	Fatigue assessment for the appraise stage of Ross and Blake field Upgrade. In two months we completed drawing review, spectral fatigue assessment, Rule Based check, and recommendations.	FPSO
Engineering Criticality Assessment of welds in castings	2011	Worked with The Welding Institute, owner and Class to predict fatigue lives of partial penetration butt welds.	Heavy lift
Strength and Fatigue assessment of hull structure in way of lifting gear	2012	Reduced project time by getting agreement from class to use a combined long term stress and fatigue assessment rather than separate strength and fatigue assessment.	Heavy lift
Fatigue assessment of hull structure in way of new build sheerleg	2012	Identified 12 critical areas. Yard accepted all recommendations. Confirmed non-redundant structure robust	Heavy lift
Check of shear stress in welds adjacent to the strength deck	2012	Work carried out at short notice to assist the owner with discussion with the yard. The yard agreed to increase the weld sizes and subsequently confirmed by their own analysis	Pipe layer
Strength check of foundations of sheer legs	2012	Assisted owner and yard with ECA assessment of thick plates to determine need for post weld heat treatment	Heavy lift
Displacement of lift system	2012	Used by client design of lifting gear	Heavy lift
In place analysis of self-elevating unit	2012	First SSA from Fairlead, carried out at short notice, delivered an early report and the vessel sailed on time.	Jackup
In place analysis of self-elevating unit	2012	Various Site assessments for elevated storm survival condition	Jackup
Investigation of buckling of legs of self-elevating unit during leg extraction	2012	Detailed analysis of leg buckling during excessive inclination of jackup unit. Root cause and recommendations for repair.	Jackup
Hydrodynamic and risk analysis of green seas on bow, input to new build design standards	2012	Delivered to a very tight schedule. Client incorporated risk analysis into new build specification for the largest order of new build tankers in the world of 2012.	Tanker
In place analysis of self-elevating unit	2013	Site assessment for new field. Identified preload risk areas overlooked by warranty surveyor.	Jackup
Repair procedure for legs of self-elevating unit	2013	Check of repair, check of deflections and stress during repair. Identified design improvements in way of welds. Identified buckling issue and solution in way of temporary reinforcement. All recommendations implemented by client.	Jackup
Repair afloat of bottom floors in way of crane of lift barge	2013	Checked induced and residual stress due to repair afloat. Identified buckling issue with proposed repair.	Jackup
Punch through risk assessment for self-elevating units and safe weather windows	2013	Assessment of punch though risk and development of safe weather windows with reduced preload. Job turned around at short notice and client able to carry out lift	Jackup
Transportation study for cargo with 40m overhang from deck side	2013	Calculation of short and long term statistics of relative wave elevation in a restricted weather window. Worked with operator to develop allowable heading rosettes and roll monitoring procedure.	Jackup
Hydro validation and update of clients internal procedures	2013	Third party validation of client’s hydrodynamic calculations. Update of clients internal programs and calculation sheets.	Jackup
Check of deck capacity of transportation vessel when carrying heavy deck load	2013	Deck load exceeded class allowable. Site specific design wave analysis demonstrated compliance with class requirements. Class approval completed, class fees under budget	Jackup
Damage investigation and repair	2013	Damage to bottom structure caused 200mm indentation. Root cause analysis via nonlinear plastic analysis and calibration with digital scans. Recommendations for repair. Repair carried out	Jackup
Bottom stabilised lift	2013	Determine weather windows for bottom stabilised lift with wind wave and current. Worked with the owner and Warranty Surveyor. Warranty Surveyor accepted and the lifts were successful, saved one month of time off hire and the project was completed on schedule.	Jackup
Root cause analysis, ECA, and solution of side cracking in FPSO	2013	Investigation of the mechanism of failure. Risk of future repair and maintenance. IIP developed via ECA for safe inspection intervals. All recommendations implemented.	FPSO
Life extension and In Service Inspection Plan of semi-submersible	2013	Spectral fatigue analysis, modifications and weld dressing to achieve 5 years inspection intervals. Updated IIP and yard work package to carry out the works.	Semi-submersible
Drag coefficients of jackup legs	2013	Literature review and CFD calculation to derive more accurate Cd values for octagonal legs at hyper critical Reynolds Number (4 e7). Lower drag coefficients accepted by Warranty Surveyor and Class. One extra month operation time achieved and works completed successfully without incident	Jackup
Collision analysis of floating unit and fixed platform	2013	Preliminary report delivered early to meet client’s contract negotiations. Damage stability check for minor risk of puncturing side tanks. Recommendations for reducing risk implemented.	Jacket
Collision analysis of floating unit and fixed platform	2013	Preliminary report delivered early to meet client’s contract negotiations. Damage stability check for minor risk of puncturing side tanks. Recommendations for reducing risk implemented.	Semi-submersible
Site assessment of Load out	2014	Site assessment of load out in heavy current for self-loading transportation vessel. Warranty surveyor accepted operating limits and loadout completed on schedule.	Jackup
Strength assessment of Semi Sub anchor bolsters	2013	Strength of bolsters for mooring loads in harbour. Linear static FE and rule checks of strength and buckling	Semi-submersible
Scour and punch through mitigation for jackup	2013	Scour and punch through mitigation for jackup vessel on superficial clay layer. Work carried out with geotechnics consultancy. Warranty surveyor accepted procedure and project completed on schedule.	Jackup
Strength check of welds in Walkway of Semi Sub	2014	Close out class comments about strength of poorly designed welds in escape walkway. Class comments were closed out.	Semi-submersible
Modification of spudcans to jack on boulders	2013-2014	Strength Assessment of modifications to spudcans of jackup vessel to jackup on seabed with embedded boulders. Feasibility study, costing and comparison of 4 alternative solutions. Worked with classification society to gain approval in time for project start. Helped shipyard with material grade sourcing.	Jackup
Air Gap and impact check of Semi-Submersible	2014	Checked impact loads on the deck of semi-submersible. Identified critical areas and carried out plastic analysis. Produced monthly risk matrix for green water at lifeboats.	Semi-submersible
ECA of one sided welds in 40mm plate	2014	Class requested annual inspection of one sided welds in 40mm plate. Plate difficult to inspect. Crack propagation assessment. Resolved class concerns about root cracks, inspection intervals increased from annual to round robin 5 years interval, with 15% of locations inspected each five years.	Jackup
Model tests of jackup legs	2014	Model tests carried out for jackup legs, Built model, measurement system, towing system. Drag coefficients obtained, increased operational season by approx. one month.	Jackup
Site assessment of jackup on limestone bedrock.	2014	Site assessment of jackup working on near surface bedrock of friable limestone. Worked in conjunction with geotechnics consultancy. Warranty surveyor accepted report and client secured hire contract.	Jackup
Assessment of pile oscillations.	2013-2014	Assessment of pile oscillations for pile installation vessel. Time domain simulation of double pendulum, statistical analysis of response. Production of traffic light matrix for allowable seastates.	Jackup
Strength and fatigue design of wave energy converter	2014	Partner in consortium developing a wave energy converter, winner of Innovate UK awards. The device is 50% more efficient than existing units. Structural design of model test and large scale sea trial, approved by UK MMO for use near shore in the Solway Firth.	Energy device
Design appraisal of new build North Sea FPSO	2014	Overview of fatigue performance of primary and secondary connections. Work carried out in two phases to meet yard design schedule. Yard agreed with and implemented all recommendations.	FPSO
Root cause analysis and solution of cracking problem on FPSO	2014	FPSO in harsh environment cracks at COT boundary. Recommendations provided in four weeks turnaround. Fabrication drawings. All recommendations agreed.	FPSO
Review of client longitudinal strength calculations	2014	Update of client tools for strength check. Improved calculation and identified errors in the Class approved yard longitudinal strength calculations and Trim and Stability Booklet. Report submitted as part of client’s tender, client won the contract.	FPSO
Bunkering weather window limits	2014	Client wished to bunker in part open water, weather window derived based on hydrodynamic calculations and derivation of loads from metocean reports. Client cut turnaround time in port and saved approx. 5 days on the project.	Jackup
Site assessments of Jackup	2014	Various site assessments of jackup units	Jackup
Air gap and impact check of Semi-Submersible	2014	Airgap check for lifeboats, impact loads and strength of main deck	Jackup
Repair recommendations for minor crack in semi-submersible main deck	2014	Advised repair team on bracket sizes. Temporary repair procedure. Worked with TWI to confirm weld procedures and consumables.	Semi-submersible
Training for buckling and strength	2014	Training clients engineers for Marine Rules	Training
Longitudinal Strength	2014	Spreadsheet tool for planning marine operations	Jackup
Intact and Damage Stability	2013-2014	Update of damage stability cases for collision study. Intact Stability spreadsheet tool for planning marine operations,	Semi-submersible
Fatigue analysis and determining safe inspection intervals	2015	Fatigue screening and determine safe inspection intervals for existing units	FPSO
Transportation studies	2015	Specification of grillage height to achieve design weather window during transit.	Jackup
Increase of preload of jackup	2015	Determine capability of hull to increase preload to increase foundation strength and storm survival Hs.	Jackup
Various SSA of jackups	2015	SSA to ISO19905 , geotechnical, structural and hydro checks. Strategies for managing scour punch through and other risks	Jackup
Producing allowable loading plan for strength deck	2015	Determine allowable sea fastening loads at frame girder intersections and distributed and intermediate loads. Produce loading plans	Jackup
Mooring calculations	2015	Check and redesign of mooring lines to DNV rules.	Jackup
Update of client hydrodynamic tools	2015	Update clients in house Hydrodynamic analysis tools	Jackup
Design of hydro electric turbine installation	2015	Tidal energy recovery system from dock gates	Energy device
Remedial repairs to hull in service	2015	Remedial repair, fabrication drawings, weld sequence and class approval for repair in service	FPSO
Peer review and trouble shooting of modification to offshore unit	2015	Assisted owner to manage over design and scope creep of strengthening in way of new process topsides plant	FPSO
Crane foundation design	2015	Design of pedestal and deck strengthening	Semi-submersible
Lifeboat and davit launch design	2015	Various projects involving upgrade of lifeboats and FRC to LSA code	Semi-submersible
Feasibility study for FPSO West of Shetland	2015	Check airgap and slamming loads in Solan field	FPSO
Peer review and recommendations to improve fatigue life of new build FPSO	2015	Reviewed yard proposals, identified low fatigue lives based on damage incidents and rule requirements, made recommendations for reinforcement, yard accepted and implemented the change	FPSO
Life extension, scantling reassessment	2015	Thickness measurements with wastage above 2015 rule allowable but less than build stage rule allowable. Reassessed scantlings to new rules and Class approved the thinner plate as “as built”	Semi-submersible
Local deck strength	2015	Check deck strength in way of heavy topsides	Semi-submersible
Docking plan	2015	Peer review of docking procedure on a lifting barge. Identified misalignment of load path and shear yield, minor redesign of grillage to avoid yield. Docking completed without incident.	Jackup
Design of anode attachment system	2015	Design of anode attachments for piles, design halved the installation time of the project.	Coastal
Cable protection	2015	Weather protection for underdeck cables to comply with MODU code and lower wave impact pressures	Semi-submersible
Safe inspection interval and in service inspection plans	2015	Update of clients in service inspection plans using in service data from and guidance from IIW. New inspection plan approved by class	Semi-submersible
SSA: Foundation design for heavy lifts in port and in the field	2016	Calculation of max static, functional and environmental loads during lift in harbour and offshore in the 50 year storm. Design of foundations for the extreme loads.	Jackup
Engineering Criticality Assessment and In Service Inspection Plan	2016	Spectral fatigue analysis, fracture mechanics, crack growth rates, specification of NDE and safe inspection intervals	Semi-submersible
Life Extension of MODU	2016	Reassessment of existing non redundant structure to new Rules, design wave analysis	Semi-submersible
Life Extension of MODU	2017	Reassessment of existing structure to new Rules, design wave analysis, fatigue analysis , crack growth and ECA to determine safe inspection intervals	Semi-submersible
OTG13 assessment of MODU	2016	Check risk of slamming impact. Hydrodynamic analysis to calculate relative wave elevation and airgaps	Semi-submersible
Reinforcement of MODU for wave impact	2017	Elasto-plastic analysis via hand calcs and Nonlinear dynamic finite element analysis Design of reinforcement to class rules. Inspection of steel work work offshore.	Semi-submersible
SSA of offshore wind farm with risks of punch though and minimal airgap	2017	Managing risks of jacking in areas with a risk of punch through by accurately calculating the loads at the foundations	Jackup
Mooring analysis in port	2017	Develop mooring plan and allowable wind speeds for mooring a jackup unit in port	Jackup
Design of resin anchors for floating bollard system	2017	Calculate of design loads, design resin anchor and reinforcement of concrete in way of attachments of a floating bollard system to a lead in jetty.	Coastal
Upgrade of lead in jetty to allow crew transfer vessels for offshore wind farm to moor	2017	Check steel structure and make recommendations for improvements to meet the design standard	Coastal
Design of seafastening for Launch and recovery System of an ROV	2017	Design welds and grillage to class Rules.	Semi-submersible
Risk assessment of green water on deck	2017	Check risk of green water and water ingress to accommodation block on the deck of an offshore unit. Recommendations to manage the risk were implemented	Semi-submersible
Survey and recommendations for cracking problem in superstructure	2017	Survey offshore of cracks in the superstructure, root cause analysis and recommendations for remedial action	Jackup
Various SSAs for installation of topside modules , substations and rotors by jackups	2017	Approved by warranty surveyor	Jackup
Establish safe limit of boulders on sea bed for jackup unit	2017	Approved by warranty surveyor	Jackup
Establish procedure for a self elevating unit to jack down in difficult ground conditions	2017	Approved by warranty surveyor	Jackup
Survey cracks in floating structures	2017	Used for subsequent redesign.	Semi-submersible
Design modifications to reduce risk of cracking	2017	Modifications approved by class, carried out by operator whilst on project, no downtime needed , cracks no longer occur	Semi-submersible
Pressure test of windows off floating structure	2017	Designed test rig and carried out to Class and Norwegian PSA requirements, Approved by Class. Vessel operating in harsh environment	Semi-submersible
Design of crane upgrade on floating asset	2107	Modifications approved by Class and successfully installed during special survey	Semi-submersible
Special survey of floating assert	2018	Identify critical areas and plan areas for inspection. Approved by Class	Semi-submersible
Slamming loads on offshore structure	2018	Design modifications and operational restrictions.Approved by Class.	Semi-submersible
HSE surveys of floating asset	2018	Identify critical areas and plan areas for inspection. Approved by Class	Semi-submersible
Reinforce windows of floating assert to withstand slamming loads	2018	Covers designed. Approved by Class. Fitted by owner offshore with no downtime,	Semi-submersible
Operating HS OTG14	2018	Safe operating Hs for floatel, approved by Class and implemented by owner	Semi-submersible
OTG14 assessment and reinforcements for various assets	2018	Reinforcements to meet Class and PSA requirements, Approved by Class. Modifications carried out	Semi-submersible
Renewal survey plan	2018	Planning areas to inspect based on predicted fatigue lives and safe inspection intervals.	Semi-submersible
Blast strength	2018	Checking strength of superstructure to withstand blast loads	Semi-submersible
Watertight doors	2018	Design of watertight doors and frame to withstand slamming loads	Semi-submersible
Operating HS OTG14	2019	Safe operating Hs for floatel, approved by Class and implemented by owner	Semi-submersible
Establish safe loading limits and inspection intervals to manage cracks in deck of FPSO in harsh environment	2018	Loading limits adopted, FPSO safely managed through winter till repairs in Summer weather window	FPSO
Various SSA of jackups	2018	Derived allowable Hs vs Tp. Approved by warranty surveyor	Jackup
Establish weather window for transporting overhanging cargo on heavy lift barge	2018	Derived allowable Hs vs Tp. Approved by warranty surveyor	Jackup
Root cause analysis of damage in lashing gear of jackup unit and recommendations for modifications	2018	Recommendations for improving the lashing system and fitting accumulators to maintain tension carried out	Jackup
Modifications and safe inspection intervals for cracks in jackhouse of self elevating unit	2018	Safe inspection intervals approved by class.	Jackup
Assist owner with discussions with PSA	2018	Acted as owner’s expert during discussions about structural integrity of the asset. Plan agreed with PSA	Semi-submersible
Operating HS OTG14	2019	Safe operating Hs for floatel, approved by Class and implemented by owner	Semi-submersible
Design practical repair for FPSO to be carried out during production on riser	2019	Repair approved by class and carried out by operator, FPSO safely continued till next planned docking	FPSO
Establish safe loading limits and inspection intervals to manage cracks in deck of FPSO in harsh environment	2019	Followed a successful project on a similar FPSO. Loading limits adopted, FPSO safely managed through winter till repairs in Summer weather window	FPSO
Establish safe loading limits and inspection intervals to manage cracks in bilge of FPSO in harsh environment	2019	Loading limits balanced with requirements to manage deck cracks as well.	FPSO
Survey and HAZID for floating structure	2019	Survey vessel and assist owner to develop HAZID	Semi-submersible
Site specific allowable Hs for operating	2019	Approved by Class	Semi-submersible
Software to automatically predict long term airgap and safe weather windows during transportation on heavy lift barge	2020	Developed potential flow code to carry out sea-keeping analysis and calculate long term airgap in arbitrary scatter diagrams	Jackup

“ I was really impressed with the 'can do' attitude ...your response was easily the best of the three organisations we had executing the same task ”

“ What more can I say? You all pulled the rabbit out of the hat. ”

“ Very pleased that things are ahead of schedule, thanks and well done. ”

“ Just a note to express my great satisfaction with the wave load determination work you carried out for me recently. I was really impressed with the 'can do' attitude towards getting us a satisfactory answer ”