Port State Control and Ship Detention
The legal basis of port state control, how inspections and risk profiles work, what detention means, and the Paris MoU's latest figures.
Port state control (PSC) is the inspection of foreign ships in a country's ports to check that the ship, her equipment and her crew meet international rules. A ship with serious deficiencies is detained until they are put right. Responsibility for ship standards rests first with the flag state, which is why IMO describes PSC as a safety net for catching substandard ships.[1] Under the Paris MoU, the regime covering Europe and the North Atlantic, officers carried out 16,474 inspections in 2025 and detained ships 688 times, a rate of 4.18%, up from 4.03% in 2024.[2][3]
Legal Basis
The authority comes from the conventions themselves, of which SOLAS regulation I/19 is the best known example, and the procedures are collected in IMO resolution A.1185(33).[4] The UN Convention on the Law of the Sea (UNCLOS) adds two articles. Article 219 lets a state stop a ship in port that breaches seaworthiness rules and threatens the marine environment, allowing her to go only as far as the nearest suitable repair yard. Article 218 lets a port state, on stated conditions, investigate and bring proceedings against a ship voluntarily in port over discharges made outside its own waters.[5] How far those powers reach in a given case depends on treaty membership and national law.
IMO resolution A.682(17) encouraged states to cooperate regionally.[1] The logic is practical. A ship calls at a string of countries, and without shared records each port would start from nothing. A regional memorandum of understanding (MoU) therefore pools inspection results in a common database.
Stages of an Inspection
The port state control officer (PSCO) starts with an initial inspection: certificates, seafarers' qualifications, log books and a general look at the ship. If papers are missing or the condition of the vessel does not match them, the officer has clear grounds for a more detailed inspection. That means going down to the engine room, seeing fire and lifesaving equipment run, and possibly watching the crew carry out an emergency drill.
The Paris MoU has a third category, the expanded inspection. It applies to every high risk ship, and to bulk carriers, gas tankers, oil tankers, chemical tankers and passenger ships older than 12 years.[6]
Fuel paperwork is part of the routine too. MARPOL Annex VI keeps the bunker delivery note on board for three years, available for inspection, and the MARPOL sample for at least twelve months.[7] Officers test compliance with the IMO 2020 sulphur limit starting from these documents and can take a sample if they have clear grounds. The Mediterranean has been an emission control area since 1 May 2025, so 0.10% is the figure that applies in ports there.
Risk Profile and Inspection Frequency
The New Inspection Regime, in force since 1 January 2011, sorts ships by risk. The profile draws on ship type and age, the performance of the flag, the classification society and the ISM manager, and the ship's own record of inspections, deficiencies and detentions. It is recalculated daily.[6]
| Ship risk profile | Window after last inspection |
|---|---|
| High risk | 5-6 months |
| Standard risk | 10-12 months |
| Low risk | 24-36 months |
Source: West of England P&I Club summary of the Paris MoU regime.[6]
A ship calling inside her window is Priority II and may be selected. A ship calling after the window has closed is Priority I and must be inspected before she leaves. Overriding factors, such as class suspended for safety reasons or a collision or grounding en route, make a ship Priority I regardless of when she was last inspected.[6]
Deficiencies and Detention
Each deficiency goes in the report with a deadline: before departure, at the next port or within a set period. Detention is the heaviest outcome. Türkiye's regulation describes it as the response to deficiencies that, alone or together, make the ship unseaworthy and create a significant danger, with written notice going to the flag state and classification society.[8]
Detention should not be confused with ship arrest. Detention is an administrative safety measure that ends when the fault is fixed. Arrest is a court order securing a claim, and belongs to maritime law proper. Fines and prosecution vary from country to country.
These were the most common areas of deficiency under the Paris MoU in 2025.[3]
| Area | Share of total |
|---|---|
| Fire safety (SOLAS II-2) | 16.8% |
| Structural and electrical equipment (SOLAS II-1) | 11.6% |
| Health protection, medical care and social security (MLC Title IV) | 10.0% |
| ISM-related deficiencies | 4.5% |
Repeat detentions lead to bans. Under the 2011 regime, a ship on a black-listed flag detained more than twice in 36 months, or on a grey-listed flag detained more than twice in 24 months, is refused access to Paris MoU ports. The first ban runs 3 months, the second 12 and the third 24, and a fourth is permanent.[6] Nineteen ships were banned in 2025, above the figures of recent years.[3]
Flag Performance Lists
The Paris MoU sorts flags into white, grey and black lists on three years of inspection and detention results, counting only flags with at least 30 inspections. For 2023 to 2025 it assessed 69 flags: 40 white, 19 grey and 10 black. The Cayman Islands, Sweden and Norway head the white list, while Cameroon, Tanzania and the Comoros sit at the bottom of the black list.[3] The results feed into risk profile calculations from 1 July 2026.[2] Recognised organisations are ranked in the same way, with 31 reaching the 60 inspection threshold.[3] Their job is explained under classification societies.
Origins of the Paris MoU
In March 1978 the Liberian-flagged tanker Amoco Cadiz ran aground off Brittany and broke into three. That same year eight North Sea states signed the Hague Memorandum. It had begun as an agreement on shipboard living and working conditions, and public pressure pushed the scope towards safety and pollution. In 1982 fourteen European countries agreed to coordinate their inspections under the Paris Memorandum, which took effect on 1 July that year.[4][9]
The memorandum now has 28 administrations, most of coastal Europe plus Canada, with the Russian Federation suspended. Its 46th amendment took effect on 1 July 2025.[9][10]
Regional Regimes and Türkiye
IMO lists nine regional MoUs. The US Coast Guard runs its own programme, usually counted as a tenth regime.[1]
| Regime | Region |
|---|---|
| Paris MoU | Europe and the North Atlantic |
| Tokyo MoU | Asia and the Pacific |
| Acuerdo de Viña del Mar | Latin America |
| Caribbean MoU | Caribbean |
| Abuja MoU | West and Central Africa |
| Black Sea MoU | Black Sea |
| Mediterranean MoU | Mediterranean |
| Indian Ocean MoU | Indian Ocean |
| Riyadh MoU | Gulf |
Türkiye does not appear among the Paris MoU members. It belongs to the Black Sea and Mediterranean MoUs. The Black Sea MoU was signed in 2000 by six coastal states and has its secretariat in Istanbul.[11] Turkish-flagged ships calling at European ports are inspected under the Paris regime, so the flag's place on the Paris lists still matters to Turkish owners.
Türkiye's new Port State Control Regulation entered into force on 22 September 2025, replacing the 2006 rules. Inspections may take place without notice. A ship detained three or more times within 36 months faces a 12 month ban. The owner, operator or flag state has one month to appeal to the maritime authority, and the appeal does not suspend the detention.[8] In a live case the current text and a lawyer should be consulted.
Preparing for an Inspection
The deficiency figures show where to look first. Fire doors alone account for 3.1% of findings and seafarers' employment agreements for 1.3%.[3] Before arrival, it pays to check certificates close to expiry, fire and lifesaving equipment, log books and crew documents, and to keep bunker delivery notes and samples to hand. The same care applies when arranging a stem: delivery documents need the right ship name and IMO number, so state both clearly at the enquiry stage.
Frequently asked questions
What is port state control?
Port state control (PSC) is the inspection of foreign ships in a country's ports to check that the ship, her equipment and her crew meet international rules.
What does PSC stand for?
Port state control: a state's inspection of foreign ships in its ports against international rules.
Is detention the same as ship arrest?
No. Detention is an administrative decision on safety grounds. Arrest is a measure ordered by a court to secure a claim.
Is Türkiye a member of the Paris MoU?
No. Türkiye is a party to the Black Sea and Mediterranean MoUs. Turkish-flagged ships are inspected under the Paris regime when they call at its ports.
How often is a ship inspected?
Under the Paris MoU it depends on risk. The window opens 5-6 months after the last inspection for a high risk ship, 10-12 months for standard risk and 24-36 months for low risk.
Sources
- International Maritime Organization. Port State Control.
- Paris MoU. Press Release, 2025 Annual Report, July 2026; 2025 Performance Lists, 1 July 2026.
- HANSA. Port State Control: Paris MoU Sees an Increase in the Number of Ships Detained Once Again, 2026.
- Deutsche Flagge (German Federal Maritime and Hydrographic Agency). Port State Control, History.
- United Nations. Convention on the Law of the Sea, Part XII, Articles 218 and 219, 1982.
- West of England P&I Club. Port State Control: Paris MoU New Inspection Regime, 2010.
- REMPEC. MARPOL Annex VI and Its Sulphur Regulation, guidance document.
- Gürülkan Law Firm. The New Port State Control Regulation in Türkiye, 29 September 2025.
- Paris MoU. About Us; 35 Years of Paris MoU, 12 September 2017.
- Paris MoU. The Paris Memorandum of Understanding on Port State Control.
- Black Sea MoU. About.
