Complete Lifecycle Support for Offshore Mooring and Product Transfer Infrastructure
OSC Marine provides installation, inspection, maintenance, repair, integrity management and decommissioning services for offshore and nearshore mooring systems.
Our integrated capabilities combine offshore construction, commercial diving, remotely operated vehicle (ROV) services, subsea inspection, survey support, engineering and marine logistics. This enables OSC Marine to support mooring infrastructure throughout its operational lifecycle, from initial installation and commissioning to maintenance, life extension, and final removal.
We support operators, terminal owners, asset managers and marine contractors throughout Southern, East and West Africa, as well as Guyana, South America.
Mooring Systems and Facilities OSC Marine Supports
OSC Marine provides technical services for:
- Single Buoy Mooring and Single Point Mooring (SBM/SPM) systems
- Catenary Anchor Leg Mooring (CALM) buoys
- Single Anchor Leg Mooring (SALM) systems
- Multi-Buoy Mooring (MBM) systems
- Conventional Buoy Mooring (CBM) systems
- Turret mooring systems
- Offshore loading and offloading terminals
- Marine transfer and import/export facilities
- Crude oil, refined product and petrochemical transfer infrastructure
Our services are planned around the configuration, condition, operating environment, and integrity requirements of each asset.
Mooring System Installation & Offshore Construction
OSC Marine provides offshore construction, installation, deployment and commissioning support for single point moorings, multi-buoy moorings, offshore transfer systems and associated subsea infrastructure.
Our teams coordinate subsea operations, survey activities, marine assets, ROV systems, diving personnel, and specialist equipment to support controlled and efficient project execution.
Installation Services
- Seabed survey verification and installation planning
- Drag, suction, gravity and pile anchor installation
- Mooring chain deployment and tensioning
- Anchor leg assembly installation
- Buoy body and rotating turntable installation
- Floating and subsea hose deployment
- Pipeline end manifold (PLEM) installation
- Subsea pipeline and PLEM tie-ins
- Riser installation and connection
- Subsea manifold installation support
- Positioning, metrology and verification surveys
- ROV-assisted installation monitoring
- Diving support where required
- Commissioning and pre-operational verification
Integrated Project Support
- Offshore construction management
- ROV systems and operational support
- Commercial diving operations
- Survey and positioning
- Marine logistics and vessel coordination
- Heavy-lift and deployment support
- Quality assurance and quality control
- Installation verification and reporting
Mooring Inspection & Compliance Surveys
Mooring systems are critical for safety, operational, and environmental assets. Regular inspection provides operators with the information required to assess condition, identify deterioration and plan maintenance before defects affect system availability.
OSC Marine conducts inspection campaigns using ROVs, commercial divers, survey systems, and specialist measurement equipment. Inspection scopes can be developed to support operator requirements, asset integrity programmes, class surveys, and applicable statutory obligations.
Mooring System Inspection
- Anchor condition assessment
- Chain wear measurements
- Chain elongation assessment
- Shackle and connector inspection
- Swivel inspection
- Hawser inspection
- Fairlead condition assessment
- Chain angle, catenary profile and mooring-line alignment verification
- Chain stopper, fairlead and load-transfer point inspection
- Mooring line and anchor leg inspection
- General visual inspection (GVI)
- Detailed visual inspection (DVI)
- Non-destructive testing support
Structural Inspection
- Buoy hull condition surveys
- Corrosion assessment
- Coating condition surveys
- Structural crack identification
- Cathodic protection potential readings, anode condition checks and anode wastage assessment
- Marine growth assessment
- Structural component inspection
Product Transfer System Inspection
- Floating hose inspection
- Subsea hose inspection
- Hose string and coupling assessment
- Hose configuration verification, including Chinese lantern, Lazy-S, Steep-S or project-specific arrangements
- Flotation collar, buoyancy element, clamp, flange and hose underside condition checks
- Product swivel inspection
- Riser inspection
- Pipeline end manifold inspection
- PLEM base, manifold, flange, bolting and hydraulic umbilical inspection
- Subsea valve, actuator and associated control-function testing support
- Leak investigation and detection
- Product transfer system condition assessment
Seabed and Geotechnical Assessment
- Anchor stability verification
- Scour assessment
- Seabed movement monitoring
- Free-span surveys
- Debris and obstruction surveys
- Seabed condition assessment
Inspection Deliverables
Inspection data is compiled into clear, practical deliverables that support engineering review and maintenance planning.
Deliverables may include:
- Inspection reports
- Video and photographic records
- As-built drawing verification and inspection against current asset records
- As-found and as-left inspection records with sketches, measurements, orientation references and anomaly locations
- Digital asset registers
- Chain measurement reports
- Corrosion assessments
- Defect and anomaly registers
- Fitness-for-service recommendations
- Repair prioritisation plans
- Compliance documentation
- Diving and ROV compliance documentation, including project plans, risk assessments, permits to work, method statements, job packs, toolbox records, dive logs and equipment certification records
- Recommended inspection intervals
Asset Integrity, Engineering & Life Extension
OSC Marine provides integrated asset integrity, engineering and life extension services for offshore and nearshore mooring systems, transfer infrastructure and associated subsea assets.
Our approach combines inspection data, engineering analysis and operational considerations to help operators understand asset condition, manage risk, optimise maintenance strategies and extend service life.
Whether supporting routine integrity programmes, component replacement projects, refurbishment campaigns or end-of-life decision-making, OSC Marine delivers practical technical solutions throughout the asset lifecycle.
Asset Integrity & Engineering Services
- Condition assessment and trend analysis
- Remaining life assessment
- Mooring and structural analysis
- Chain wear and life calculations
- Fatigue assessment
- Corrosion assessment and progression modelling
- Anchor holding capacity assessment
- Risk-based inspection planning
- Condition monitoring programmes
- Asset integrity databases and digital asset management
- Failure investigations and root cause analysis
- Independent technical verification
- Repair and replacement prioritisation
- Integrity management programme development
Life Extension & Upgrade Support
Ageing mooring systems often require targeted intervention to maintain operational reliability, regulatory compliance and asset integrity. OSC Marine develops life extension strategies based on inspection findings, engineering assessments and operational requirements.
Services may include:
- Structural reassessment and re-certification support
- Chain replacement programmes
- Corrosion mitigation programmes
- Cathodic protection upgrades
- Buoy and mooring system refurbishment
- Integrity restoration work scopes
- Capacity and performance upgrades
- Mooring system modification support
- End-of-life replacement planning
- Life extension project management
Deliverables
Deliverables are tailored to the requirements of each asset and may include:
- Asset integrity assessments
- Engineering reports and recommendations
- Remaining life evaluations
- Fitness-for-service reviews
- Risk assessments
- Repair specifications
- Upgrade recommendations
- Maintenance and inspection plans
- Replacement strategies
- Integrity management documentation
Through the integration of inspection, engineering and operational expertise, OSC Marine helps clients maximise asset reliability, improve maintenance planning, support regulatory compliance and extend the operational life of critical offshore mooring infrastructure.
Mooring Maintenance, Repair & Refurbishment
OSC Marine supports planned and corrective maintenance activities to maximise asset availability, operational reliability and service life.
Repair scopes can be undertaken as part of a scheduled maintenance programme, inspection follow-up campaign, emergency intervention or wider asset refurbishment project.
Mechanical Repairs
- Mooring chain replacement
- Shackle and connector replacement
- Swivel inspection and repair
- Bearing replacement
- Hawser replacement
- Fairlead repairs
- Quick-release component servicing
- Mooring component change-outs
Structural Repairs
- Underwater welding support
- Structural reinforcement
- Coating repairs
- Corrosion remediation
- Cathodic protection replacement
- Localised structural repair
- Buoy refurbishment
Hose and Transfer System Repairs
- Floating hose replacement
- Subsea hose replacement
- Marine loading hose change-outs
- Hose string and coupling replacement
- Leak investigation
- Pipeline tie-in support
- Product transfer system repairs
- Transfer system maintenance
ROV, Diving & Subsea Intervention Services
OSC Marine provides integrated subsea inspection, maintenance and intervention services using remotely operated vehicles (ROVs), commercial diving teams and specialist subsea tooling.
The most appropriate methodology is selected based on water depth, environmental conditions, asset configuration, operational constraints, and project requirements. ROV and diving operations can be deployed independently or as part of a combined intervention strategy.
Inspection Services
- General visual inspection (GVI)
- Detailed visual inspection (DVI)
- Mooring chain inspection and measurement
- Anchor, shackle and connector inspection
- Structural condition assessment
- Cathodic protection surveys
- Marine growth assessment
- Seabed and scour surveys
- Non-destructive testing support
- Subsea video and photographic recording
Maintenance & Intervention Services
- Cleaning and marine growth removal
- Debris and obstruction removal
- Hose replacement support
- Chain and connector replacement
- Cathodic protection replacement
- Underwater cutting and welding support
- Installation and connection support
- Intervention tooling deployment
- Emergency subsea intervention
- Post-maintenance verification
Integrated Subsea Support
ROV and diving operations can be integrated with engineering, survey, marine construction and vessel support services to provide a coordinated solution for inspection, maintenance, repair and integrity management projects.
Floating Hose & Product Transfer System Services
OSC Marine provides specialist inspection, maintenance and replacement services for marine hoses and offshore cargo transfer infrastructure.
These services are applicable to SBM/SPM, CALM and MBM systems, as well as offshore loading terminals and nearshore import/export facilities.
Transfer System Services
- Floating hose inspection
- Submarine hose inspection
- Marine loading hose replacement
- Hose string and coupling assessment
- Hose integrity management
- Leak investigation
- Pipeline and manifold tie-ins
- Riser installation and maintenance
- Product swivel inspection support
- Transfer system maintenance
- Hose recovery and deployment
- Post-installation testing and verification
Emergency Response, Recovery & Salvage Support
OSC Marine provides rapid-response support for damaged or failed mooring systems and offshore transfer infrastructure.
Our emergency capabilities combine marine operations, diving, ROV, survey, repair and salvage support to assist with asset stabilisation, recovery and restoration.
Emergency Support
- Hawser failure response
- Chain failure recovery
- Failed mooring recovery
- Lost anchor location and recovery
- Emergency buoy stabilisation
- Hose rupture response
- Leak investigation
- Emergency subsea repairs
- Vessel incident support
- Marine salvage assistance
- Pollution response support
- Emergency repair campaigns
Each response is planned according to the condition of the asset, operational risks, environmental considerations, and the equipment required to execute the work safely.
Decommissioning & Asset Removal
OSC Marine supports the safe and environmentally responsible for retirement, replacement and removal of offshore mooring infrastructure.
Decommissioning scopes can include engineering, disconnection, recovery, lifting, transportation, and post-removal site verification.
Decommissioning Services
- Decommissioning planning
- Pipeline and hose disconnection
- Chain and anchor recovery
- Buoy removal
- Subsea infrastructure removal
- PLEM and manifold removal support
- Seabed debris recovery
- Environmental clearance surveys
- Site clearance verification
- Site rehabilitation verification
- Post-decommissioning reporting
Support Vessels & Small Craft
OSC Marine provides support vessels and small craft for SBM/SPM operations, diving projects, crew transfers and emergency response. Vessel arrangements are adapted to local site requirements and operating procedures.
Support Vessel Services
- Static towing: Supports tanker berthing and remains connected at the stern, ready to assist with tanker positioning at the SBM.
- Standby support: Maintains operational readiness and a radio watch during loading or discharge operations.
- Night patrol: Monitors for pollution and vessels entering the SBM exclusion zone during hours of darkness.
Small Craft & Fast Rescue Craft
Small craft and workboats transfer divers, crew and equipment between the buoy, dive station and support vessel. Fast rescue craft provide emergency recovery capability and suitable accommodation for the rescue team, casualties and a stretcher.
All craft are selected for the operating environment and must comply with applicable international, regional and local requirements.
Safety & Environmental Standards
Safety and environmental responsibility are integral to every OSC Marine operation. Work scopes are planned in accordance with recognised industry standards, applicable legislation and site-specific requirements.
Key controls include:
- OCIMF guidance for applicable offshore mooring operations
- Adoption of the more stringent requirement where local legislation applies
- Energy isolation and Lockout/Tagout (LOTO)
- Hand and power tool safety
- Environmental protection standards
- Offshore oil spill response planning
- Appropriate personal protective equipment (PPE)
All requirements are assessed and incorporated into project-specific procedures before work begins.
Mooring System-Specific Services
Service requirements vary according to the design, configuration, and operating environment of each mooring system.
CALM Buoy Systems
Catenary Anchor Leg Mooring systems use multiple catenary anchor legs to maintain the buoy position while allowing the connected vessel to weathervane around the mooring.
OSC Marine services include:
- Anchor and chain inspection
- Chain measurement surveys
- Floating and subsea hose maintenance
- Product swivel inspection support
- Buoy hull inspection
- ROV integrity surveys
- Anchor leg replacement
- Corrosion and cathodic protection assessment
SALM Systems
Single Anchor Leg Mooring systems require focused inspection and engineering assessment of the single-leg structure and its foundation.
OSC Marine services include:
- Universal joint inspection
- Structural fatigue assessment
- Single-leg integrity assessment
- Anchor foundation monitoring
- Riser and transfer system inspection
- Structural and mechanical repair support
Multi-Buoy Mooring Systems
Multi-Buoy Mooring systems use several mooring buoys to secure tankers during cargo transfer operations. Loads are distributed across a wider arrangement of anchors, chains and mooring lines, requiring coordinated inspection and maintenance across the complete mooring spread.
OSC Marine services include:
- Mooring spread surveys
- Anchor and chain inspection
- Buoy hull and buoyancy assessment
- Mooring line and hawser inspection
- Chain and connector replacement
- Seabed and anchor position surveys
- Product hose inspection and replacement
- Buoy refurbishment
- Navigation aid inspection support
Conventional Buoy Mooring Systems
OSC Marine supports the inspection, maintenance and repair of Conventional Buoy Mooring systems used at ports, terminals and nearshore transfer facilities.
Services include:
- Navigation aid inspection support
- Buoyancy system maintenance
- Chain and connector replacement
- Seabed anchor surveys
- Buoy inspection and refurbishment
- Corrosion and coating assessment
- Mooring spread verification
Turret Mooring Systems
OSC Marine provides subsea inspection and intervention support for internal and external turret mooring systems.
Services may include:
- Mooring line inspection
- Chain and connector surveys
- Anchor assessment
- Riser and flexible inspection
- Seabed surveys
- Cathodic protection surveys
- Marine growth assessment
- ROV and diving intervention support
Integrated Marine Capability
OSC Marine combines specialist personnel, marine assets and technical systems to provide a coordinated service across offshore and nearshore operating environments.
Our capabilities include:
- Offshore construction and project management
- Commercial diving
- ROV inspection and intervention
- Survey and positioning
- Marine logistics
- Support vessels and workboats
- Subsea engineering
- Inspection reporting and data management
- Asset integrity assessment
- Emergency response and salvage support
- Quality, health, safety and environmental management
OSC Marine’s wider website position’s reliability, quality, safety and customer satisfaction as central operating values, supported by integrated technical services for demanding marine environments.
Frequently Asked Questions:
What is the difference between permanent and temporary moorings?
Permanent moorings are designed for long-term offshore operations and remain in place for the life of a facility or terminal. Temporary moorings are installed for short-term activities such as construction, maintenance, surveys or emergency operations and are removed once the work is complete.
What is the difference between an SBM and an SPM?
An SBM (Single Buoy Mooring) is a type of SPM (Single Point Mooring). SPM is the broader term used for offshore mooring systems that allow vessels to moor and transfer products through a single connection point. SBM is commonly used to describe offshore loading and offloading buoy systems used in the oil, gas and energy sectors.
What industries use SBM and SPM systems?
SBM and SPM systems are commonly used in:
- Offshore oil and gas production
- Crude oil export terminals
- Refined product import and export facilities
- Petrochemical terminals
- LNG and energy infrastructure projects
- Offshore marine transfer operations
What is the role of OCIMF in offshore mooring operations?
The Oil Companies International Marine Forum (OCIMF) publishes guidance and industry best practices relating to offshore mooring systems, tanker operations, marine hose management and terminal safety. Many operators use OCIMF guidance when developing inspection, maintenance and operational procedures.
What is a buoy?
A buoy is a floating object placed on the water’s surface to mark a location, provide navigation guidance, collect data, or serve as an attachment point for vessels and equipment. It is designed to remain visible while floating above the water.
What is a mooring buoy?
A mooring buoy is a floating buoy connected to an anchor or mooring system on the seabed, allowing boats and vessels to tie up without dropping their own anchors. It acts as the visible access point to the mooring system beneath the water.
What are buoys used for?
Buoys are used to mark channels, hazards, and safe navigation routes, as well as to support mooring systems, scientific monitoring equipment, and offshore operations. They help improve safety, navigation, and operational efficiency in marine environments.
What is a shipping buoy?
A shipping buoy is a marine marker used to guide commercial vessels safely through shipping channels, ports, and waterways. It helps indicate navigation routes, hazards, traffic separation zones, and other important information for ship operators.