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A class survey is a formal technical inspection conducted by a classification society — organisations such as DNV, Lloyd's Register, Bureau Veritas, American Bureau of Shipping (ABS), or RINA — to assess whether a ship's hull, machinery, electrical systems, and safety equipment meet the applicable class rules and standards. Ships that pass their class surveys maintain their classification, which is a fundamental prerequisite for commercial trading: without class, a vessel cannot obtain or renew its trading certificates, cannot be insured on standard marine insurance terms, and will be refused entry by many ports and terminals.
Classification societies set technical standards for ship design, construction, and ongoing maintenance that go beyond the minimum safety requirements of international conventions such as SOLAS. Classification rules are developed by the societies themselves, based on decades of technical research, incident analysis, and industry consultation, and are regularly updated to reflect advances in technology and understanding of failure modes. Ships are assigned a class notation that describes their type, build standard, and operational scope — and which must be maintained through regular surveys.
The relationship between classification and statutory certification is important to understand. Many flag states delegate the verification of statutory certificate requirements — SOLAS, MARPOL, and others — to classification societies acting as Recognised Organisations (ROs). This means that the same surveyor who conducts a class survey may also be verifying compliance with international conventions on behalf of the flag state. The two roles are distinct but often conducted simultaneously, making the classification society a central compliance partner for shipowners and managers.
Classification surveys are conducted on a structured cycle. The Annual Survey is a high-level examination carried out each year to confirm that the ship's overall condition remains consistent with its class. The Intermediate Survey (conducted around the 2.5-year mark in the five-year class cycle) is more detailed and includes a closer examination of structure and machinery. The Special Survey, conducted every five years, is the most comprehensive examination — covering hull structure, machinery, electrical systems, and safety equipment in detail, typically coinciding with a scheduled dry-docking.
Dry-docking surveys are required at prescribed intervals — typically every two and a half years for most vessel types, though some newer vessels qualify for extended intervals through Condition Assessment Programmes (CAP) or Enhanced Survey Programmes (ESP). Dry-docking allows underwater hull inspection, propeller and rudder examination, cathodic protection assessment, and sea chest inspection — examinations that cannot be carried out when the vessel is afloat. Planning a dry-docking involves extensive coordination between the technical team, the classification society, shipyard, and supply chain.
In addition to these scheduled surveys, classification societies conduct Damage Surveys following incidents — grounding, collision, fire, flooding — to assess the impact on class and determine what repairs are required before the vessel can return to service. Companies may also request voluntary appraisals for vessels being purchased or sold, providing an independent assessment of condition for commercial due diligence purposes.
When a classification society surveyor identifies a deficiency during a survey — a structural deterioration, equipment that does not meet class standards, or a maintenance gap — they have several options. Minor observations may be recorded as recommendations to be addressed before the next survey. More significant findings may result in a Condition of Class (CoC) — a formal notation that the ship's class is conditional on the specified repair or action being completed within a defined timeframe.
A Condition of Class is a serious matter. It is visible in class society databases, reported to the flag state, and may be noted by Port State Control inspectors. If a CoC is not resolved within its stipulated deadline, the vessel's class may be suspended — meaning it cannot trade until the issue is rectified and verified by a surveyor. In extreme cases, where a surveyor judges that the vessel's condition presents an immediate danger, class may be withdrawn on the spot.
Outstanding survey recommendations — less urgent than CoCs but still requiring action — accumulate in the vessel's class file. A vessel with a large number of outstanding recommendations signals to surveyors and PSC inspectors that the company's technical management is not keeping pace with the vessel's needs. This can trigger more detailed inspections and increase the risk of finding additional deficiencies. Staying ahead of recommendations is therefore an important function of good Planned Maintenance System management.
Effective class survey preparation begins months before the surveyor arrives — not in the days before. A well-run Planned Maintenance System gives the technical superintendent visibility of all maintenance jobs that are overdue or due within the survey preparation window, all outstanding class recommendations from previous surveys, and the status of all class-related certificates. With this information, the technical team can plan the repair work, order spare parts, and coordinate with the classification society to agree on the scope and schedule of the survey well in advance.
The procurement planning for a class survey — particularly a Special Survey involving dry-docking — is substantial. Spare parts, consumables, specialist equipment, and third-party services must all be sourced and delivered to the shipyard on time. Delays in parts procurement are one of the most common causes of dry-docking overruns, which can significantly exceed the planned budget and schedule. Integrating procurement management with the survey preparation plan in the fleet management system reduces this risk.
The connection between class survey preparation and QHSE management management is also significant. A thorough pre-survey inspection of the vessel — carried out by the technical superintendent or a third-party inspector — can identify issues before the class surveyor arrives, giving the company the opportunity to address them proactively. Non-conformities identified during Port State Control inspections in the period before a scheduled survey should also be reviewed as potential class-related issues, since the two inspection regimes often find overlapping deficiencies.
Infoship tracks all class-related certificates, survey due dates, Conditions of Class, and outstanding recommendations in a single system — accessible to both the vessel crew and the shore technical team in real time. Automated alerts flag approaching survey deadlines months in advance, giving the technical superintendent sufficient time to plan the survey scope, engage the classification society, and initiate the spare parts and service procurement process through Infoship's procurement module.
During the survey preparation phase, all maintenance records relevant to the class surveyor's scope are available in Infoship — timestamped, linked to the relevant equipment, and filterable by date range and job type. This removes the time-consuming process of compiling maintenance evidence from paper records or disparate systems, and gives the surveyor confidence that the vessel's maintenance history is complete and accurately documented. After the survey, any new conditions of class or recommendations are recorded directly in the system and tracked through to closure, maintaining the continuous record that underpins effective class management.
