Port State Control inspections: how they work and how to prepare your ships

What is a port State control inspection?

Port State control is the inspection of foreign ships in national ports. IMO conventions allow a port State to check that a visiting ship complies with the standards its flag State has certified. The flag State remains primarily responsible; PSC is a second line of defence against substandard ships.

Most port States work through regional agreements so that inspections are shared and ships are not inspected at every port. IMO lists nine regimes: the Paris MoU (Europe and the North Atlantic), Tokyo MoU (Asia-Pacific), Viña del Mar Agreement (Latin America), Caribbean, Abuja, Black Sea, Mediterranean, Indian Ocean and Riyadh MoUs. The United States Coast Guard runs its own programme.

The procedures inspectors follow are set out by IMO in resolution A.1206(34), Procedures for Port State Control, 2025, which replaced resolution A.1185(33). Each MoU adds its own instructions, targeting rules and deficiency codes.

Which conventions does a PSC officer check?

A PSC officer (PSCO) checks compliance with the conventions the port State has ratified and that apply to the ship. In practice that means:

Under the "no more favourable treatment" principle, ships flying the flag of a State that has not ratified a convention are inspected to the same standard.

How are ships selected for PSC inspection?

Ships are selected by risk, not at random. In the Paris MoU, every ship has a ship risk profile recalculated daily: high risk (HRS), standard risk (SRS) or low risk (LRS). The profile uses:

• ship type and age;
• flag performance (the White, Grey and Black lists);
• recognised organisation (class) performance;
• company performance;
• deficiencies and detentions in the previous 36 months.

The profile sets the inspection window after the last Paris MoU inspection:

A ship inside its window is Priority II and may be inspected. Once the window has closed it is Priority I and must be inspected. Overriding factors, such as a collision or grounding, or class suspended for safety reasons, trigger an inspection whatever the window. Unexpected factors, such as a report from a pilot or port authority, let the port State decide whether to inspect.

Company performance is part of the profile, so a poor record on one ship affects the risk profile of the whole fleet under the same DOC company.

The USCG uses its own targeting matrix, which scores the owner or operator, flag State, class society, the ship's compliance history and ship type, and assigns a boarding priority. Well-performing ships from qualifying flags can enter the QUALSHIP 21 programme and receive reduced examinations.

What are the types of PSC inspection?

There are three levels of inspection, and the PSCO decides how far to go based on what is found.

Clear grounds are evidence found during the initial inspection. Examples include missing or invalid certificates, serious corrosion or damage, missing or inoperative equipment, crew who cannot carry out essential shipboard operations, and evidence that operational drills were not carried out. A poor crew response in a fire or abandon ship drill is one of the most common routes into a more detailed inspection.

What happens when deficiencies are found?

Each deficiency is recorded with a deficiency code and an action. In the Paris MoU system, codes identify the area: for example, code 15150 is used for ISM deficiencies, and codes in the 07100 range cover fire safety items such as fire detection and fire doors. Common actions include:

• rectified (action code 10): fixed and verified during the inspection;
• rectify before departure (action code 17): the Master must fix it before the ship sails;
• grounds for detention (action code 30): the deficiency is serious enough to detain the ship.

A ship is detained when deficiencies are clearly hazardous to safety, health or the environment. The ship stays in port until the deficiencies are rectified or the port State is satisfied it can sail safely to a repair yard. Detentions are published, and they count against the flag, the recognised organisation and the company.

When several deficiencies in the same area point to a failure of the safety management system, the PSCO may also record an ISM deficiency, which can itself be detainable.

What gets a ship banned?

In the Paris MoU, a ship is refused access (banned) after three detentions within 36 months if it flies a Black-listed flag, or within 24 months if its flag is on the Grey list. A ship can also be banned for leaving port in breach of a detention or for failing to call at an agreed repair yard. The first ban lasts at least three months and the second at least 12 months. A further detention after a third ban leads to permanent refusal of access.

What are the most common PSC deficiencies?

Fire safety tops the list. In its 2025 Annual Report, the Paris MoU recorded 16,474 inspections, 688 detentions (a detention rate of 4.18%, up from 4.03% in 2024) and 19 bans. The largest deficiency groups were:

ISM deficiencies made up 4.5% of the total. Rest hours are a frequent finding under both STCW and MLC; see our hours of rest guide for how inspectors test the records.

Which PSC campaigns are running now?

The Paris and Tokyo MoUs ran a joint Concentrated Inspection Campaign (CIC) on cargo securing from 1 September to 30 November 2026. During a CIC, inspectors add a set questionnaire to routine inspections, and deficiencies found can still lead to detention. Both MoUs have announced enclosed space entry as the CIC topic for 2027, which links to the revised IMO recommendations in resolution MSC.581(110).

How should you prepare a ship for a PSC inspection?

Good PSC preparation is not a pre-arrival tidy-up. It is the ship's normal condition, checked often enough that nothing drifts. A practical routine:

1. Know the ship's risk profile and window. Check the profile in the MoU database before each call in a PSC region, and plan for an inspection when the window is open.
2. Keep certificates and documents in order. Check expiry dates, endorsements and annual surveys well before arrival, including the DOC copy, SMC, ISSC, MLC certificate and DMLC.
3. Close the last inspection. Make sure every deficiency from the previous report is closed with evidence on board.
4. Test the equipment PSCOs test. Emergency generator, emergency fire pump, fire doors, fire detection, quick-closing valves, lifeboat engines and davits, oily water separator and its 15 ppm alarm.
5. Rehearse drills that look real. Crew should be able to don equipment, start pumps and communicate as they would in an emergency, not read from a card.
6. Cross-check records against reality. Oil Record Book entries, garbage record, rest hours and logbooks must tell the same story as the port call.
7. Walk the ship as an inspector would. Accommodation, galley, escape routes, engine room bilges, deck fittings, hatch covers.
8. Brief the Master and officers on how to receive the PSCO, accompany the inspection and answer questions factually.

Our separate PSC inspection checklist turns these steps into a checklist the ship can work through before arrival.

Where does an independent inspection help?

An inspection by someone from outside the ship finds what the crew no longer see. A Master Mariner who walks the ship, observes a drill and samples the records before a high-risk call can show where a PSCO would find clear grounds. If repeat deficiencies come from procedures crews cannot follow, the fix is in the SMS, not on board.

We offer PSC readiness inspections as part of our audits and inspections service. Synergetic has carried out more than 550 onboard sailing audits and pre-vetting inspections. For certificates, maintenance and rest hours, the relevant Marine X7 modules are Certificate X7, PMS X7 and Work-Ship.

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