Marine inspection is one of the most documentation-intensive sectors in the inspection industry. A single vessel passes through the hands of classification society surveyors, flag state inspectors, port state control officers, P&I club surveyors, independent marine inspection bodies, and specialist NDT providers — sometimes within weeks of each other. Each produces records. Each checks the records produced by the others. The vessel's continued commercial operation depends on the currency and integrity of certificates issued under half a dozen IMO conventions, each with its own inspection interval and record-keeping requirement.
For independent marine inspection companies — those performing hull surveys, NDT on offshore structures, underwater inspection, marine coating assessment, or cargo and condition surveys — the records challenge is compounded by the mobility of the asset. A vessel is not a fixed installation. It moves between jurisdictions, changes flag, changes class, changes ownership. Its inspection history needs to follow it. And the inspection body that produced a survey report five years ago may be asked to produce that report again — by a new owner, a P&I club, or a court.
This guide covers what marine inspection encompasses, the classification society and regulatory frameworks that govern it, the technical methods used for hull and offshore inspection, and what purpose-built software can do to make marine inspection records manageable, retrievable, and audit-ready.
What Marine and Ship Inspection Covers
Marine inspection is not a single activity. It is a family of distinct inspection types performed by different parties at different points in a vessel's operating life — and the records from each type must be maintained and accessible independently.
Hull inspection is the examination of a vessel's outer shell plating, structural members, frames, stringers, floors, bulkheads, and watertight integrity. Hull condition directly affects structural safety, buoyancy, and stability. Hull inspection may be visual, or it may include thickness measurement and coating assessment. It is performed in drydock during scheduled class surveys, in-water by divers or ROV for interim inspections, and by close-up survey in ballast tanks and void spaces.
Machinery inspection covers the main propulsion system (diesel engines or turbines, shafting, propellers, reduction gears), auxiliary machinery (generators, pumps, compressors, heat exchangers), piping systems, and steering gear. Classification societies require periodic surveys of all major machinery items, with some components — such as main propulsion shafts — subject to withdrawal and inspection on a defined cycle.
Cargo inspection encompasses a range of services performed by independent marine inspection bodies on behalf of cargo owners, charterers, or traders: draft surveys to verify cargo quantity loaded or discharged, condition surveys of cargo before and after a voyage, hatch and hold inspections to verify fitness for cargo, and bunker quantity surveys (BQS) measuring the quantity of fuel delivered to a vessel.
Safety equipment inspection verifies the condition, serviceability, and certification currency of lifesaving appliances (liferafts, lifeboats, EPIRBs, flares, immersion suits), firefighting systems (CO2 installations, fixed fire suppression, portable extinguishers), and emergency systems. Liferafts and firefighting equipment must be serviced and recertified at approved service stations on defined intervals — typically one year for liferafts.
Structural condition surveys are performed at specific events in a vessel's life — on purchase (pre-purchase survey), after a casualty (damage survey), for insurance purposes (condition survey), or at the request of a charterer (condition of class). These are typically carried out by independent marine surveyors rather than classification societies, and they produce a condition report that goes to the party commissioning the survey, not to the class society's records.
Marine NDT is a specialised subset of structural inspection that applies non-destructive testing methods to quantify material properties — thickness remaining after corrosion, weld integrity, crack detection in highly stressed components — rather than relying solely on visual assessment. NDT on marine structures requires personnel qualified under both NDT certification schemes (PCN, ASNT, CSWIP) and, for class society work, any additional endorsements that the relevant society requires.
Offshore inspection is marine inspection applied to fixed and floating offshore structures: platforms, FPSOs (floating production, storage and offloading units), jack-up rigs, semi-submersible drilling units, and associated subsea infrastructure. Offshore inspection is subject to its own regulatory frameworks — in Australia, the Offshore Petroleum and Greenhouse Gas Storage Act (OPGGSA) and the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) requirements — as well as the requirements of whichever classification society has assigned class to the structure.
The parties that perform these inspection types include:
- Classification societies — performing annual, intermediate, and special surveys as well as condition of class assessments on the vessels and offshore structures they class
- Flag state administrations — conducting statutory inspections or delegating this function to recognised organisations (typically the classification societies)
- Port state control authorities — inspecting vessels at port to verify compliance with international conventions, under regional MOU arrangements
- Independent marine inspection bodies — performing condition surveys, cargo inspection, bunker surveys, and specialist NDT on behalf of shipowners, charterers, cargo interests, P&I clubs, and insurers
- Specialist offshore NDT providers — performing thickness measurement, ACFM inspection, and underwater inspection on offshore structures under contract to operators or asset owners
Classification Society Framework
The classification society system is the bedrock of commercial shipping safety. Founded on the premise that independent technical verification of a vessel's condition provides assurance to insurers, charterers, and cargo owners, the major societies have operated continuously — in some cases for over two centuries — as the de facto safety and quality standard for the global merchant fleet.
The International Association of Classification Societies (IACS) represents the major societies: Lloyd's Register (LR), founded in 1760 and headquartered in London; Det Norske Veritas (DNV), a Norwegian society formed by the 2013 merger of DNV and Germanischer Lloyd; Bureau Veritas (BV), a French society with roots in maritime classification since 1828; American Bureau of Shipping (ABS), headquartered in Houston; ClassNK (Nippon Kaiji Kyokai), the Japanese society and one of the largest by tonnage classed; RINA (Registro Italiano Navale), the Italian society; and the Korean Register (KR). Together, IACS member societies class over 90 percent of world ocean-going tonnage.
IACS produces Unified Requirements (URs) — technical standards that apply uniformly across all member societies — covering structural strength, hull girder longitudinal strength, stability, machinery, automation, and other technical areas. Because IACS URs are incorporated into each society's own rules, a vessel classed by DNV is built to rules that are broadly comparable in their technical underpinning to those of a vessel classed by Lloyd's Register.
What classification societies inspect and when:
Classification surveys operate on a five-year cycle tied to the Special Survey, which is the most comprehensive structural examination a vessel undergoes. Within the cycle:
- Annual Survey is required every 12 months within a three-month window around the anniversary date. The surveyor examines the hull exterior (in-water or in drydock), tests firefighting and lifesaving equipment, inspects machinery spaces, verifies that statutory certificates are current, and reviews the vessel's deficiency history since the previous survey. An Annual Survey endorsement is recorded in the Survey Report File and is required for the vessel's certificates to remain valid.
- Intermediate Survey falls at approximately the 2.5-year mark (within six months either side of the second annual survey) and is more detailed. It includes examination of the hull structure in accessible areas, testing of sea valves and ship-side fittings, inspection of cargo hold structures, and — for tankers — internal examination of tanks. IACS Unified Requirement Z10 governs the scope of intermediate surveys for bulk carriers and tankers.
- Special Survey is required every five years and involves a thorough examination of the entire vessel. All tanks, void spaces, and cofferdams must be cleaned and gas-freed for internal inspection. Hull plating and structural members are thickness-gauged according to the society's sampling plan. Close-up survey (CUS) — direct physical access by a surveyor within arm's reach — is required for nominated structural members identified as high-stress or corrosion-prone. The propulsion shaft must be withdrawn for examination unless the society's continuous machinery survey (CMS) scheme allows an extended interval. Statutory certificates are renewed on completion of the Special Survey.
- Docking Survey accompanies the Special Survey and requires the vessel to be placed in a drydock or slipway for external hull examination. The bottom plating, sea chests, propeller, rudder, and underwater fittings are inspected. Thickness gauging of the underwater hull plating is carried out. Any structural renewal or coating work identified is completed before the vessel is undocked.
Class notation is the alphanumeric designation assigned to a vessel by the class society that defines the vessel type, service limitations, and the standards to which it was built. For example, Lloyd's Register might assign a notation of +100A1 to indicate that the vessel was built and surveyed to LR's highest structural standard for seagoing service. DNV's notation +1A1 carries equivalent meaning within the DNV system. Class notations also record notations for machinery class, ice class, equipment, and special service features.
Certificate of Class is the document issued by the classification society confirming that the vessel maintains class as of the date of survey. The Certificate of Class is a private document between the society and the shipowner — it is not a statutory certificate under an IMO convention, though its currency is a prerequisite for maintaining the statutory certificates that flag states and port state control authorities inspect.
Survey Report File is the accumulated record of all surveys performed on a vessel by the class society. For a vessel that has been in class for twenty years, the Survey Report File contains the records of every annual, intermediate, and special survey, all deficiency records, all repair approvals, and all subsequent verifications. Accessing this file — or equivalent historical records — is essential when a shipowner changes class society (class transfer) or when a vessel changes hands and the new owner needs to understand the structural history.
Regulatory Framework: SOLAS, MARPOL, ISM and Beyond
Classification is a private technical standard. The regulatory framework for ship inspection is set by the International Maritime Organization (IMO) through a series of international conventions, each covering a specific area of maritime safety, pollution prevention, or crew welfare. Understanding these conventions is essential for any inspection body that issues certificates or maintains records under them, because port state control officers inspect compliance with the conventions — not with the class society's rules.
SOLAS — Safety of Life at Sea (IMO Convention, most recent consolidated version in force from 2002, with numerous amendments): SOLAS is the most fundamental of the IMO conventions. It sets minimum safety standards for ship construction, equipment, and operation. Its 14 chapters cover topics including subdivision and damage stability (Chapter II-1), fire protection and detection (Chapter II-2), lifesaving appliances (Chapter III), radio communications (Chapter IV), safety of navigation (Chapter V), carriage of cargoes (Chapter VI), management for the safe operation of ships — the ISM Code (Chapter IX) — and special measures to enhance maritime security — the ISPS Code (Chapter XI-2). Every cargo ship of 500 GT or more and every passenger ship on international voyages must carry SOLAS certificates: the Safety Construction Certificate, the Safety Equipment Certificate, and the Safety Radio Certificate. These are issued by or on behalf of the flag state (usually by the classification society acting as a recognised organisation) and must be presented to port state control on demand.
MARPOL — International Convention for the Prevention of Pollution from Ships (IMO, 1973 as modified by the 1978 Protocol; entered into force 1983): MARPOL's six annexes cover pollution from oil (Annex I), noxious liquid substances (Annex II), harmful substances carried in packaged form (Annex III), sewage (Annex IV), garbage (Annex V), and air pollution from ships (Annex VI — which covers SOx, NOx, and greenhouse gas emissions). For inspection purposes, Annex I is the most records-intensive: ships must maintain an Oil Record Book (ORB) recording every transfer, discharge, and disposal of oily water from machinery spaces and cargo operations. The ORB must be kept on board for three years and must be available for inspection at any port. Flag state inspectors and PSC officers routinely examine the ORB for signs of falsification — a pattern of entries that is physically implausible (excessive separator efficiency, illogical discharge volumes) is a trigger for detention.
ISM Code — International Safety Management Code (SOLAS Chapter IX, mandatory since 1998 for cargo ships of 500 GT or more): The ISM Code requires shipping companies to implement a documented Safety Management System (SMS) covering safety policy, procedures for safe operation and response to emergencies, non-conformance reporting, internal audits, and management review. The flag state (or a recognised organisation on its behalf) audits the company's SMS and issues a Document of Compliance (DOC) to the company and a Safety Management Certificate (SMC) to each vessel. Both the DOC and SMC are five-year certificates with an intermediate verification (at 2.5 years). Port state control officers inspect both documents on every visit — an expired or invalid SMC is a ground for immediate detention. The SMS itself — as a living document system with its complete records of non-conformances, corrective actions, drills, and audits — is subject to examination during flag state and PSC inspections.
ISPS Code — International Ship and Port Facility Security Code (SOLAS Chapter XI-2, mandatory since July 2004): The ISPS Code requires ships and port facilities to implement security plans approved by the flag state or port state authority. Ships must carry an International Ship Security Certificate (ISSC) and a Ship Security Plan (SSP). The Ship Security Officer (SSO) is required to maintain records of security threats, incidents, drills, and inspections. PSC inspectors verify the currency of the ISSC and may, in some circumstances, review security records.
MLC 2006 — Maritime Labour Convention (ILO, entered into force 2013): MLC 2006 is sometimes described as the seafarers' bill of rights. It sets minimum standards for seafarer employment conditions, working hours, accommodation, recreational facilities, food and catering, health protection, medical care, and social security. Ships of 500 GT or more on international voyages must carry a Maritime Labour Certificate (MLC) and a Declaration of Maritime Labour Compliance (DMLC). PSC officers inspect living conditions on board and review the documentation of seafarers' employment agreements, wage records, rest hour records, and complaints procedures.
Flag state inspection is the inspection of a vessel by or on behalf of the administration of the country whose flag the vessel flies. Flag states have primary responsibility under international law for ensuring that their flagged vessels comply with IMO conventions. In practice, most flag states delegate the conduct of statutory surveys and the issuance of certificates to recognised organisations — in most cases, the major classification societies, which are formally authorised as recognised organisations (ROs) under SOLAS Regulation XI-1/1. Flag state inspectors may conduct supplementary audits, particularly under the IMO's Voluntary Member State Audit Scheme (VIMSAS), or may respond to incidents involving their flagged vessels.
Port state control (PSC) inspections are inspections conducted by the maritime authority of the port state — the country where the vessel is calling — on foreign-flagged vessels. PSC is organised through regional MOU arrangements: the Paris MOU covers Europe and the North Atlantic; the Tokyo MOU covers the Asia-Pacific (including Australia, through the Australian Maritime Safety Authority, AMSA); the Indian Ocean MOU, Abuja MOU, Acuerdo de Viña del Mar (Latin America), the Gulf Cooperation Council MOU, the Black Sea MOU, the Mediterranean MOU, and the Riyadh MOU cover their respective regions. Each MOU operates a targeting system that prioritises vessels for inspection based on risk factors — vessel age, flag state performance, class society performance, previous deficiency history, and vessel type. PSC inspections can result in deficiency notices (which must be rectified before the next inspection or at the next port) or detention (which prevents the vessel from sailing until deficiencies are corrected). An unbroken string of clean PSC inspections is, in practice, one of the most commercially important records a vessel can maintain.
Hull and Structural Inspection
Hull inspection is the technical core of ship and marine structure inspection. The hull is the vessel's primary safety-critical component — structural failure of the hull can result in loss of the vessel and all persons on board. Classification societies, independent surveyors, and specialist inspection bodies all perform hull inspection using a combination of visual, dimensional, and NDT methods.
In-water survey (underwater hull inspection) is the inspection of a vessel's underwater hull without placing the vessel in drydock. It may be performed by divers or, increasingly, by remotely operated vehicles (ROVs) equipped with cameras, sonar, and UT probes. In-water surveys are used for intermediate class surveys, for pre-purchase condition assessments, and for damage surveys after a grounding or collision. The scope of an in-water survey covers the external shell plating from the keel to the waterline, sea chest gratings and grids, propeller blades and shaft seals, rudder and steering gear, bow thruster tunnels, and bilge keels. IACS Unified Requirement Z17 sets the standards for in-water surveys as an alternative to drydocking. Not all class surveys can be satisfied by an in-water survey — the five-year Special Survey always requires drydocking for bottom inspection and anodic protection assessment.
Drydock survey places the vessel in a graving dock, floating dock, or on a slipway to allow the external underwater hull to be fully examined, cleaned, and coated. The drydock survey for a Special Survey involves: full visual examination of the external shell plating and bottom; measurement of shell plate thickness at the bottom and bilge areas; inspection of sea chests, sea valves, and overboard discharges; propeller blade examination (including blade thickness measurement and edge condition); rudder stock and bearing clearance measurement; anchor and chain inspection; cathodic protection (sacrificial anodes or impressed current system) assessment and renewal; and application of antifouling coating and any structural repair work identified during the survey.
Close-up survey (CUS) is a survey of structural members carried out by a surveyor at close range — typically defined as within arm's reach — to allow visual detection of corrosion, cracking, deformation, and coating breakdown that cannot be assessed from a distance. Close-up survey is required for specific structural elements at each major class survey, with the extent increasing at each five-year cycle. IACS UR S31 specifies the CUS requirements for bulk carriers; UR Z10 covers tankers. Close-up survey of ballast tanks and cargo holds typically requires staging, climbing equipment, or an ROV to access the upper areas of large tanks. The surveyor produces a written record of findings at each location — the close-up survey report — which forms part of the class survey record.
Thickness measurement (UT gauging) is the quantitative core of the Special Survey hull assessment. Ultrasonic gauges are used to measure the remaining steel thickness at a defined grid of measurement points across the vessel's hull plating, deck plating, structural frames, longitudinals, floors, and bulkheads. Results are compared against the as-built dimensions (from the scantling drawings) and against the allowable diminution limits set by IACS Unified Requirement S31 (for hull structure generally) and by the class society's rules for specific vessel types. Where thickness has fallen below the allowable minimum, steel renewal is required before the vessel can be returned to service. The measurement records — including the gauge readings, the grid reference, the date, the instrument used, and the operator — form a critical part of the Special Survey documentation. For a large bulk carrier or tanker, a full thickness measurement campaign can produce thousands of individual readings.
Coating condition assessment evaluates the condition of the protective coating applied to steel surfaces — ballast tanks, void spaces, cargo hold frames and tank tops, and the external underwater hull — to assess its effectiveness and predict the rate of future corrosion. IACS Unified Requirement Z9 uses a three-level coating condition rating: GOOD (coating in good condition with only minor rust staining), FAIR (coating with rust staining over more than 20% of the area, or hard scale in addition to rust staining), and POOR (general breakdown of coating, rust on more than 20% of the surface, or pitting). A POOR coating condition rating triggers additional thickness measurement requirements at subsequent surveys. Coating condition is assessed visually by the surveyor during close-up survey, and the findings are recorded section by section in the coating condition report. This report, alongside the thickness measurement record, gives the owner and class society a predictive picture of the vessel's structural condition trend over the survey cycle.
Corrosion mapping is the spatial representation of thickness loss across a structural member or panel, produced from a grid of UT readings. Rather than reporting average thickness loss or maximum pitting depth, a corrosion map shows the pattern of thinning across the surface — which allows structural analysts to assess whether the pattern is consistent with general corrosion (uniform across the panel), pitting (localised deep losses), or stress-corrosion cracking (following weld lines or structural discontinuities). Corrosion maps are produced from large thickness measurement datasets and are increasingly generated digitally, allowing the data from successive surveys to be overlaid and the rate of corrosion progress to be calculated.
Structural integrity assessment uses the thickness measurement data, corrosion mapping, and close-up survey findings to evaluate whether the vessel's structural members retain adequate strength for continued service. Classification societies have developed rule-based methods for this assessment, and finite element analysis (FEA) may be used for complex cases. The output is a determination of what repairs or renewals are required before the next survey, and what — if any — operational restrictions apply in the interim. For older vessels approaching the end of their commercial life, structural integrity assessment is a critical input to the decision about whether continued operation is economically viable.
Marine NDT Methods and Their Applications
Marine structures present a demanding environment for NDT work: aggressive corrosive conditions accelerate material degradation; access is often difficult in confined tanks, chain lockers, and underwater; and the coating systems applied to marine structures complicate many conventional NDT methods. The NDT methods used in marine inspection are selected for their ability to provide reliable results in these conditions.
Ultrasonic thickness (UT) gauging is the dominant NDT method in marine hull inspection. A hand-held ultrasonic gauge uses a piezoelectric transducer to send an ultrasonic pulse through the plate; the time for the pulse to reflect from the back wall is converted to a thickness reading. Modern digital UT gauges are accurate to ±0.1 mm and can measure through paint coatings, eliminating the need to remove coating at each measurement point. For classification society thickness measurement campaigns, gauging is performed to the grid pattern specified in the society's rules, with more intensive measurement at structural areas where corrosion experience indicates greater risk — strakes adjacent to frames, areas around openings and penetrations, and areas of known poor coating condition. UT gauging records for a Special Survey include the gauge type and serial number, calibration block reference, the calibration record for the gauge, and the full set of readings for every measurement point, each referenced to the structural location using the vessel's frame number and plate marking system.
Radiographic testing (RT) is used in marine inspection primarily for weld examination — on repair welds, on structural modifications, and on welds in critical locations identified by the class surveyor. Conventional RT uses an X-ray source or a gamma-ray source (Ir-192 or Se-75 for most marine structural thicknesses) to produce a radiographic image of the weld on film or a digital detector. The image is reviewed by a qualified radiographic interpreter to detect volumetric defects — porosity, slag inclusions, lack of fusion, and cracks. RT on board a vessel is logistically demanding: radiation safety exclusion zones must be established, and access to the weld must allow correct placement of the source and detector. Digital radiography (DR) and computed radiography (CR) are increasingly used in marine inspection because they allow images to be reviewed on screen at the inspection site rather than requiring film processing.
Alternating current field measurement (ACFM) is a technique particularly well-suited to marine structural inspection. ACFM induces a uniform alternating current in the material being inspected and measures the perturbations in the magnetic field above the surface caused by cracks or other discontinuities. The key advantage of ACFM for marine work is that it can detect and size surface-breaking cracks through thick paint and coating systems — up to 5–8 mm of paint — without the need to remove the coating. This is a substantial practical advantage in marine inspection, where the cost and time involved in removing coating, performing inspection, and recoating are significant. ACFM is used on weld toes, structural connections, deck fittings, and other areas where fatigue cracking is anticipated. ACFM equipment generates a data log of the scan — the A-scan and C-scan outputs — that forms the inspection record alongside the surveyor's observation notes.
Magnetic particle inspection (MT) is used on ferromagnetic components — propeller shafts, intermediate shafts, crankshafts, crank pins, connecting rods, and anchor chain links — where surface and near-surface crack detection is required. During a drydock survey, propeller blades are examined by MT after cleaning to detect fatigue cracks near the blade root — the highest stress area. Anchor chain is examined at every Special Survey, with individual links inspected for wear, corrosion, and cracking. MT on the chain involves magnetising the link and applying wet fluorescent magnetic particles, then examining under ultraviolet light. The inspection records for MT in marine applications include the batch number of the magnetic particle consumable, the method of magnetisation, the light intensity at the inspection surface, and the findings at each inspection location.
Visual inspection of anchor chain is a statutory requirement at the Special Survey. Each shot of chain is laid out on deck or in the chain locker and each link inspected for: elongation (measured against the original dimensions recorded at new vessel delivery), wear (particularly on the inner link surface at the stud position), corrosion (pitting and general section loss), and cracking. Elongation of more than 12% of the original link length is typically the basis for renewal. The inspection record for anchor chain includes the shot number, the number of links inspected, the original dimensions, the measured dimensions, and any rejected or renewed links.
Dry film thickness (DFT) measurement of protective coatings is performed alongside structural inspection to assess the adequacy of the coating system. Marine coatings are designed to protect against corrosion in immersed and splash zone environments — inadequate DFT means inadequate protection, and over-application can affect adhesion and flexibility. DFT is measured with an electronic gauge (using magnetic induction for paint on steel). IACS Unified Requirement Z9 requires that coating condition be assessed at each class survey, and where the coating is in POOR condition, the thickness measurement program is intensified. The DFT measurement record includes the instrument type and calibration, the areas measured, and the range of readings found — cross-referenced to the coating condition assessment for the same areas.
Phased array ultrasonic testing (PAUT) is increasingly used in marine inspection for weld examination and thickness profiling. PAUT uses a multi-element transducer array to electronically steer and focus the ultrasonic beam, enabling faster scanning and more detailed imaging of weld cross-sections than conventional UT. In marine repair welding, PAUT provides a more complete volumetric examination of a repair weld than either conventional UT or RT, with the advantage that the data can be stored digitally and reviewed off-site by a senior interpreter.
Offshore and Subsea Inspection
Offshore and subsea inspection addresses a category of marine structures that are stationary — unlike vessels — but exposed to the same marine corrosion environment, wave and current loading, and the additional hazard of hydrocarbon process operations. Fixed platforms, FPSOs, jack-up rigs, semi-submersibles, subsea pipelines, and risers all require systematic inspection programs managed over the life of the structure.
Fixed offshore platforms — jacket structures supporting topsides facilities — are subject to structural inspection programs governed by classification societies (DNV, ABS, Bureau Veritas, and Lloyd's Register all have offshore structures rules) and by national regulators. In Australia, NOPSEMA administers the Offshore Petroleum and Greenhouse Gas Storage (Environment) Regulations. The structural inspection of a fixed offshore platform follows a risk-based inspection (RBI) methodology that identifies the structural members and joints most critical to structural integrity and schedules inspection frequencies accordingly. Underwater structural inspection of the jacket uses ROV-mounted cameras and UT probes to inspect welds, measure thickness at nominated locations, and assess marine growth and corrosion at the splash zone — the most aggressive corrosion environment on a platform. Marine growth (mussels, barnacles, and weed) must be removed before meaningful structural inspection can be performed, typically by mechanical cleaning tools mounted on the ROV.
FPSOs (floating production, storage and offloading units) are essentially large tankers converted or purpose-built for offshore production service. Their structural inspection requirements combine the class survey requirements applicable to tankers — including internal inspection of cargo and ballast tanks, thickness measurement, and coating assessment — with the specific structural loading conditions of a moored vessel that is not moved between surveys. FPSOs are subject to Special Survey requirements like any classed tanker, but their location (usually permanently moored at a field) makes drydocking impractical. Classification societies have developed alternative survey programs for FPSOs that allow the Special Survey to be carried out in-place, using extended in-water survey programs and internal inspection when tanks are gas-freed. The inspection records for an FPSO accumulate over the full production service life — which may be 20–30 years — and must be retrievable throughout that period.
Subsea pipelines and risers require inspection to manage corrosion (internal and external), fatigue at connections and bends, and mechanical damage from anchors, trawl gear, and seabed movement. Pipeline inspection is typically performed by intelligent pigging — an instrumented tool that travels inside the pipeline and records wall thickness (using magnetic flux leakage or ultrasonic methods), geometry (using caliper arms), and anomaly locations referenced to GPS coordinates. For risers — the sections of pipe connecting the seabed pipeline to the platform — external inspection is performed by ROV inspection and targeted UT gauging. The data from pipeline inspection runs is stored in large databases that must be retained for the life of the pipeline and are subject to regulatory reporting requirements.
Mooring systems for FPSOs and semi-submersible platforms consist of chains, wire ropes, and polyester fibre ropes attached to spread anchors or suction caissons on the seabed. Mooring system inspection covers: visual inspection of the upper chain and fairlead by ROV or diver, measurement of chain wear at selected locations, and assessment of the anchoring points. Class societies have specific rules for mooring system inspection intervals — typically triggered by time in service and by any significant weather event that may have put the mooring under extreme load. Mooring system failure has resulted in several major offshore incidents; the inspection records are treated as safety-critical.
Cathodic protection (CP) monitoring is an integral part of offshore structural inspection. Offshore structures below water are protected from corrosion by sacrificial anodes (typically aluminium alloy) or impressed current cathodic protection (ICCP) systems. ROV inspection of the anodes records their remaining mass (estimated from visual dimensions) and their potential (measured with a reference electrode probe). As anodes deplete, the protection potential drops and the steel becomes vulnerable to accelerated corrosion. CP monitoring records — taken at each inspection survey and at defined intervals — are used to calculate the expected anode life remaining and to plan anode installation prior to depletion. Classification society offshore structure rules specify the monitoring intervals and the acceptable protection potential range.
Subsea inspection software is a specialist area within marine inspection software. Managing the data from subsea pipeline inspection runs, ROV surveys of jacket structures, and cathodic protection monitoring campaigns involves very large datasets referenced to spatial coordinates (GPS positions, depth measurements, and structural drawing references). The data must be compared against historical baselines to detect changes — an anomaly in a pipeline wall that grew by 5% since the last inspection run is a very different concern from an anomaly that is stable. Software that cannot link current inspection data to historical data from the same location provides little analytical value.
Managing Marine Inspection Records with Software
The records challenge in marine inspection is qualitatively different from most land-based inspection sectors. Vessels move. They change class. They change flag. They change ownership. The inspection body that performed a hull thickness survey in Singapore two years ago may be asked — by a new owner, a P&I club, or a court of arbitration — to produce that record. The offshore platform that was surveyed annually for twenty years has an inspection history that needs to be maintained, retrievable, and usable for comparison against current findings, for the full asset life.
Most marine inspection companies that have grown beyond a handful of surveyors are managing this challenge with a combination of tools that were not designed for the purpose: job registers in spreadsheets, survey reports in Word templates stored on network drives, instrument calibration records in a separate spreadsheet maintained by the equipment manager, and personnel certification records in a third spreadsheet kept by the operations manager. The result is a records environment where retrieval is slow, currency is uncertain, and the answer to any audit question requires manual collation from multiple sources.
Vessel asset register is the foundation of a marine inspection software platform. Every vessel the inspection company has worked on should be registered with its IMO number (the unique seven-digit number assigned to a vessel by IHS Markit under IMO Resolution A.1078(28), which stays with the vessel through flag and name changes), its current name, flag state, class society, class notation, gross tonnage, vessel type, year of build, and any other identifiers the inspection body needs. All inspection jobs, survey records, and certificates issued are then linked to the vessel record. When a shipowner asks for the inspection history of a vessel their company has owned for three years — and the vessel has had four class surveys, two underwater inspections, and a pre-purchase condition survey in that time — the answer should be retrievable in seconds, not hours.
Job management for marine inspection must handle the particular scheduling complexity of marine inspection work: a vessel calling at a port may have a window of only 24–48 hours, the relevant surveyor must be dispatched immediately, and the job instruction must specify the exact scope — Annual Survey for Lloyd's Register, or condition survey for an insurance claim, or UT thickness gauging of the ballast tanks for a pre-purchase inspection. The job record must link to the relevant vessel, capture which surveyor attended, record the date, port, and scope, and track the status of the report from field data capture through review to issuance to the client.
Digital field data capture for marine inspection eliminates the paper checklist that travels from the vessel back to the office to be transcribed into a report. Surveyors working on a tablet in the field — including in offline mode when connectivity is limited — can record visual findings with attached photographs, enter UT thickness readings that are automatically flagged if they fall below the allowable diminution limit, record coating condition ratings section by section on a digital ship drawing, and note any deficiencies that will require corrective action. The field data is structured from the moment of capture, eliminating the transcription step and dramatically reducing report turnaround time.
NDT records management for marine work must accommodate the specific data types produced by marine NDT: thickness measurement grids (potentially thousands of readings per vessel), ACFM scan data, coating condition ratings by compartment, and the calibration records for every instrument used. Each NDT reading must be linked to: the vessel (by IMO number), the structural location (by frame reference, strake, or drawing reference), the instrument used (by serial number, with calibration status at time of use), the operator (by name and certification reference), and the job (by date and scope). This linkage is what allows the inspection body to answer the question: "For all thickness measurements taken with gauge serial number XYZ-1234 between January and March 2025, can you confirm the calibration status of that instrument on each date of use?" — a question that may be asked if that instrument's calibration is later found to be out of tolerance for that period.
Personnel qualifications and certification expiry for marine inspection personnel involves a more complex mix of credentials than most onshore inspection disciplines. A marine NDT surveyor performing hull thickness measurement on behalf of a classification society may need: PCN Level 2 in UT (to the requirements of BS EN ISO 9712), an additional endorsement from the relevant class society for survey work under their rules, a shipboard safety induction (STCW Basic Safety), and depending on the work, offshore safety certifications (BOSIET/HUET for offshore work). A marine coating inspector may hold NACE CIP Level 2 or BGAS-CSWIP Painting Inspector certification in addition to marine-specific qualifications. Managing all these certifications — tracking the expiry dates, generating alerts before expiry, and verifying that a particular surveyor was currently certified for a particular scope on the date they attended a particular vessel — is a task that scales poorly in a spreadsheet environment and is directly addressed by purpose-built TIC software.
Client portal for shipowners is a particularly valuable feature for marine inspection companies serving fleet operators. A shipowner managing a fleet of ten to fifteen vessels — each on its own survey cycle, calling at ports across the Asia-Pacific — needs to be able to access current survey certificates, track upcoming survey due dates, and retrieve historical survey reports without calling the inspection company's office. A client portal where the shipowner logs in and sees their entire fleet — with each vessel's current class survey status, outstanding deficiencies, upcoming Annual Survey due dates, and the complete inspection history — transforms the relationship between the inspection company and the shipowner from a reactive, phone-based service to a self-service platform.
Report generation to class society formats is a requirement for inspection bodies performing work on behalf of classification societies or presenting findings to them. Each major society — Lloyd's Register, DNV, Bureau Veritas — has its own report formats and data submission requirements for thickness measurement results, coating condition reports, and close-up survey findings. Software that allows report templates to be configured per client or per class society, and that populates those templates from the structured field data captured on tablet, eliminates a substantial volume of manual document preparation and the transcription errors that accompany it.
OMS is a purpose-built TIC platform used by inspection bodies across oil and gas, construction, and industrial sectors. For marine inspection companies, OMS provides the vessel asset register, job management, digital field data capture, NDT record management with calibration linkage, personnel qualification tracking with multi-credential support and expiry alerts, automated report generation, client portal, and a complete ISO 17020-aligned quality management system — all in a single platform. Because OMS is designed specifically for inspection bodies rather than adapted from generic project management or document management software, its data model reflects the realities of marine inspection work: the link between a vessel, a survey, an inspector, a set of instruments, and a set of findings is native to the platform rather than a workaround built on top of a generic tool.
The inspection records challenge in marine and offshore inspection is not going to simplify itself. Regulatory requirements are increasing, not decreasing — the IMO's 2023 greenhouse gas strategy is adding new monitoring and reporting obligations. Classification society digitisation programs (DNV's Veracity platform, Lloyd's Register's ShipRight programme) are moving toward digital exchange of survey data. Port state control inspection databases (the Paris MOU and Tokyo MOU both maintain vessel deficiency history publicly searchable) mean that a vessel's inspection record is, in effect, a public document. Marine inspection companies that manage their records well — in a retrievable, linkable, auditable system — are better placed to demonstrate the credibility on which their business depends.