Port State Control: Global Inspection Regime

Port state control (PSC) is the inspection of foreign-flag ships in a State’s ports to verify that the ship, its equipment, its crew and its operation comply with the international conventions that State has accepted, and to stop a substandard ship from sailing until it is put right. The IMO procedures are set by Assembly resolution A.1206(34), Procedures for Port State Control, 2025, adopted on 3 December 2025, which revokes A.1185(33). The legal powers come from the control article of each convention, read with Articles 218, 219 and 226 of the United Nations Convention on the Law of the Sea , and the work is coordinated through nine regional regimes plus the United States Coast Guard.

PSC exists because the flag State carries the primary duty for its ships and does not always discharge it. A.1206(34) paragraph 1.3.3 calls the procedures complementary to the national measures of flag State Administrations. The port State samples compliance at one call, with officers who are independent of the ship, the flag and the classification society .

Legal basis for port state control

A port State’s power to inspect a foreign ship rests on three layers: its territorial sovereignty over its own ports, the express control provisions in the IMO and ILO conventions, and the enforcement articles of UNCLOS. None of the three depends on the flag State’s consent.

UNCLOS articles 211, 218, 219 and 226

UNCLOS gives the port State four distinct footholds. Article 211(3) allows a State to set conditions for entry to its ports, internal waters or offshore terminals, provided it publicizes them and communicates them to IMO. Article 218 lets a port State investigate, and where the evidence warrants institute proceedings over, a discharge made outside its own waters in violation of applicable international rules, when the ship is voluntarily within its port.

Article 219 is the seaworthiness power. Where a ship in port violates applicable international rules on seaworthiness and thereby threatens damage to the marine environment, the port State shall, as far as practicable, take administrative measures to prevent it sailing, and may permit it to proceed only to the nearest appropriate repair yard. The threat to the marine environment is part of the test: Article 219 is not a general safety inspection power.

Article 226 sets the limits. Under 226(1)(a) a physical inspection is confined to the certificates, records and other documents the ship must carry, unless there are clear grounds to believe its condition does not correspond to the documents, the documents are insufficient to confirm a suspected violation, or it carries no valid certificates. Article 226(1)(b) requires prompt release on bond or other security, and 226(1)(c) allows release to be refused, or conditioned on proceeding to the nearest repair yard, where the ship would present an unreasonable threat of damage to the marine environment. The phrase “clear grounds” in the IMO procedures traces to this article. A fuller treatment of the jurisdictional theory belongs in port State jurisdiction .

Convention control provisions

The working powers are in the conventions themselves. A.1206(34) paragraph 1.4 lists the control provisions verbatim, and the list is the most reliable map of what a PSC officer may enforce:

SOLAS regulation IX/6.2 is the control hook for the ISM Code , and regulation XI-2/9 carries control and compliance measures for the ISPS Code . Regulation XI-1/4 extends control to operational requirements, which is why a PSC officer can test the crew at a fire or abandon-ship drill rather than only read certificates (see SOLAS Chapter XI-1 ). MARPOL’s annex-level provisions are treated in their own articles: Annex I regulation 11 , Annex II regulation 16 and the Annex IV operational control article .

COLREG 1972 is a relevant convention under paragraph 1.2.1 but has no control article in the paragraph 1.4 list. Collision-regulation shortcomings, such as defective navigation lights, are reached through SOLAS and the general clear-grounds procedure.

MLC 2006 has its own control article. Regulation 5.2.1(1) allows a port State to inspect any foreign ship calling at its port “in the normal course of its business or for operational reasons”, and 5.2.1(2) makes the Maritime Labour Certificate and the Declaration of Maritime Labour Compliance prima facie evidence of compliance. The labour side is developed in MLC port State control .

No more favourable treatment

A flag State cannot shelter its ships by staying out of a convention. A.1206(34) paragraph 1.5.1 lists the clauses that require a Party to apply the convention’s requirements to the ships of non-Parties, so that they receive no more favourable treatment: Article I(3) of the SOLAS 1988 Protocol, Article I(3) of the Load Lines 1988 Protocol, Article 5(4) of MARPOL, Article X(5) of STCW 1978, Article 3(3) of AFS 2001 and Article 3(3) of BWM 2004. MLC 2006 Article V(7) does the same for labour standards.

There are two qualifications. A port State applies only the provisions that are in force and that it has accepted (A.1206(34) paragraph 1.2.4), so a State that is not party to the BWM Convention has no BWM control power. And Appendix 2 states that the absence of a certificate on a non-Party ship is not by itself a ground for detention; the officer looks at the ship’s actual condition. The doctrine has its own entry at no more favourable treatment .

IMO Procedures for Port State Control, A.1206(34)

A.1206(34) is the global procedural code for PSC, adopted by the IMO Assembly at its 34th session on 3 December 2025 on the recommendation of MSC 109 and MEPC 83. Operative paragraph 2 invites Governments to implement the procedures when they exercise port State control, and operative paragraph 4 revokes A.1185(33). It is a recommendation: there is no entry-into-force or application date in its text, and none should be cited. IMO’s own PSC page states that the procedures are re-adopted every two years. The stub at IMO Procedures for Port State Control tracks the instrument.

The preamble records the lineage, newest first: A.1185(33), A.1155(32), A.1138(31), A.1119(30), A.1052(27), A.882(21), A.787(19), A.742(18), A.597(15) and A.466(XII). The structure has been stable for several editions: five chapters (general, inspections, contravention and detention, reporting, review) and a set of appendices that carry the technical guidance.

A.1206(34) paragraph 1.2.1 lists 14 relevant conventions: SOLAS 1974 and its 1988 Protocol, Load Lines 1966 and its 1988 Protocol, MARPOL with its 1978 and 1997 Protocols, STCW 1978, TONNAGE 1969, AFS 2001, COLREG 1972, CLC 1969, the CLC Protocol 1992 , the Bunkers Convention 2001 , BWM 2004 and the Nairobi Wreck Removal Convention 2007 . MLC 2006 and ILO Convention 147 with its Protocol are brought in by paragraph 1.2.8, through ILO guidance, rather than listed. The liability conventions are checked for their insurance certificates; a PSC officer does not assess liability.

What changed in the 2025 edition

The inspection structure is unchanged from A.1185(33). The changes are in the appendices: a new Appendix 20 with guidelines for PSC officers on security aspects; the LRIT conformance test report added as SOLAS detainable item 18 in Appendix 2; and the Annex VI detainable list in Appendix 2 extended to cover energy-efficiency documentation, set out under the environmental checks below. The Bahamas Maritime Authority summarized the same points for its fleet in Technical Alert 26-04 of 3 March 2026.

Types of inspection

A.1206(34) recognizes three stages: the initial inspection, the more detailed inspection where clear grounds exist, and, in the regional regimes, the expanded inspection for higher-risk ships. Every inspection starts at the first stage.

Initial inspection

The initial inspection is a visit on board to check the certificates and documents and to form an impression of the ship’s overall condition, its equipment and its crew. The documents to be examined are listed in Appendix 12. A.1206(34) paragraph 2.2.3 accepts electronic certificates that meet FAL.5/Circ.39/Rev.2, and viewing them on a computer satisfies the requirement that they be on board.

Where the certificates are valid and the officer’s general impression and visual observations confirm a good standard of maintenance, the inspection is normally confined to the deficiencies reported or observed. It is not a survey and does not re-test what the certificate already attests.

More detailed inspection and clear grounds

A more detailed inspection is triggered by clear grounds, defined in paragraph 1.7.2 and listed in paragraph 2.4.2. The nine categories are:

1. absence of principal equipment or arrangements required by the conventions;
2. evidence that the ship’s certificates are clearly invalid;
3. documents listed in Appendix 12 part A not on board, incomplete, not maintained or falsely maintained;
4. serious hull or structural deterioration or deficiencies that may place at risk the structural, watertight or weathertight integrity;
5. serious deficiencies in safety, pollution-prevention or navigational equipment;
6. evidence that the master or crew are not familiar with essential shipboard operations, or that such operations have not been carried out;
7. indications that key crew members cannot communicate with each other or with other persons on board;
8. the emission of false distress alerts not followed by proper cancellation procedures;
9. a report or complaint containing information that the ship appears to be substandard.

MLC 2006 Standard A5.2.1(1) sets a parallel list of four for labour conditions: the required documents are not produced or are falsely maintained; there are clear grounds that working and living conditions do not conform; there are reasonable grounds to believe the ship has changed flag to avoid compliance; or there is a complaint alleging non-conformity. The concept has its own entry at clear grounds .

Expanded inspection

The expanded inspection is a regional construct, not an IMO stage. The Paris MoU applies it at the periodic inspection of any high-risk ship, and of standard-risk or low-risk ships of the risk types (chemical, gas, oil and NLS tankers, bulk carriers and passenger ships) over 12 years old. The EU rule in amended Article 14 of Directive 2009/16/EC adds that an expanded inspection is carried out, as far as possible, by no fewer than two PSC inspectors.

Ship selection and targeting

The IMO procedures do not tell a port State which ships to board. Selection is set by each regime, and the two largest regimes use a points-based ship risk profile that combines the ship, its flag, its recognized organization and its company.

In the Paris MoU’s New Inspection Regime, launched on 1 January 2011 with the THETIS database, a ship is high risk at 5 or more weighting points under Annex 7. Ship type gives 2 points for chemical, gas and oil tankers, NLS tankers, bulk carriers and passenger ships, and age over 12 years gives 1. A low or very low company performance gives 2, a low or very low RO performance 1, and two or more detentions in 36 months 1. A black-listed flag gives 1 or 2 points depending on its band. Low-risk status needs all of a white flag, confirmation of an IMO audit, a high-performing RO recognized by a Paris MoU State, a high-performing company, at least one inspection in 36 months with no more than 5 deficiencies at each, and no detention in 36 months. The full method is at ship risk profile .

Inspection windows follow the profile. A Paris MoU high-risk ship falls due 5 to 6 months after its last inspection, a standard-risk ship 10 to 12 months, and a low-risk ship 24 to 36 months, under Annex 8. A ship with an overriding factor, such as involvement in a collision or grounding, is Priority I whatever its window.

The Tokyo MoU adopted its own New Inspection Regime on 1 January 2014 with a lower high-risk threshold of 4 points, and its 2025 inspections split 40.84 percent high risk, 45.59 percent standard risk and 13.37 percent low risk. The Tokyo MoU’s Port State Control Committee adopted Annex 2 risk-profile amendments in September 2026 that take effect on 1 January 2028.

Deficiencies and the action taken

Every non-compliance found is recorded as a deficiency against a coded category and an action the master must take. Most deficiencies are rectified within an agreed period, at the next port, or before departure; only a minority lead to detention.

The volume tells the story. In 2025 Paris MoU officers recorded 51,797 deficiencies, 4,744 of them detainable, in 16,474 inspections. Fire safety under SOLAS Chapter II-2 accounted for 16.8 percent of Paris deficiencies, SOLAS Chapter II-1 11.6 percent and MLC Title IV 10.0 percent; ISM-related deficiencies were 4.5 percent. In the Tokyo region the leading categories were fire safety (18,020 deficiencies), life-saving appliances (11,818) and working and living conditions (9,108). Fixed fire-extinguishing installations, the ISM Code and lifeboats were the top three detainable items in the Tokyo region that year.

A.1206(34) paragraph 2.3.7 deals with accidental damage. A ship damaged by accident is not issued a detention order for that damage where the four conditions in the paragraph are met. The coding systems that sit behind these records are covered in PSC deficiency codes .

Detention and release

Detention is the intervention taken when the condition of the ship or its crew does not correspond substantially with the applicable conventions, such that it cannot sail without danger to the ship or persons on board, or without presenting an unreasonable threat of harm to the marine environment. A.1206(34) defines it at paragraph 1.7.4 and sets out the guidelines in Appendix 2.

The Appendix 2 tests

Appendix 2 asks the officer two principal questions about a deficiency: timing, whether it can be put right before departure; and the re-inspection criterion, whether it must be fixed before the ship sails. It then sets eleven tests, each framed as whether the ship is “able to” carry out an essential function safely, and the officer judges the deficiency against them.

Three rules in Appendix 2 decide many disputed detentions. A combination of less serious deficiencies can justify detention even where no single item would. The detainable list is non-exhaustive in general, but for STCW the listed items are the only grounds for detention. And the absence of a certificate on a non-Party ship is not, by itself, a ground.

Notification and reporting

A detention is notified in writing to the flag Administration and, where the deficiencies relate to its statutory work, to the recognized organization (A.1206(34) paragraphs 3.5.2 and 4.1.3). Paragraph 4.1.5 requires the port State to report detentions to IMO under SOLAS regulation I/19, MARPOL article 11 or STCW article X(3). The flag State reports its remedial action through the IMO GISIS PSC module or the Appendix 17 form under paragraph 4.2.1. MARPOL allegations go to the flag State, preferably no later than 60 days after the inspection, under paragraph 4.3.1.

An MLC detention carries an extra step. In the Paris and Tokyo regions the shipowners’ and seafarers’ organizations in the port State are also notified, which reflects Standard A5.2.1(6): detention where conditions are clearly hazardous to seafarers’ safety, health or security, or the deficiency is a serious or repeated breach of the Convention.

Release and the repair-yard route

Release follows rectification and, normally, a follow-up inspection. Where the deficiencies cannot be fixed in port, A.1206(34) paragraph 3.7.3 allows the port State to permit the ship to proceed to the nearest appropriate repair yard, defined in paragraph 1.7.7, on conditions set by the port State and agreed by the flag State. This mirrors UNCLOS Articles 219 and 226(1)(c).

The condition is enforced regionally. A Paris MoU ship that sails without complying with the conditions of release, or fails to call at the indicated yard, is refused access to every port in the region. The Tokyo MoU text section 3.9 holds such a ship liable to detention at any member port until the company proves full compliance.

Appeals, detention review and undue detention

The appeal lies under the port State’s national law. A.1206(34) paragraph 2.3.11 recognizes the right and states that the appeal should not cause the detention to be suspended. A national appeal is slow and costly, so the Paris and Tokyo regimes also run a detention review, an administrative panel of other member Authorities that considers a request made through the flag State or the RO. The Tokyo MoU accepts a request within 120 days or 4 months of release, whichever is longer. Both are treated in PSC detention review .

An owner whose ship is detained without justification has a compensation route. A.1206(34) paragraph 2.1.4 states that a ship unduly detained or delayed should be entitled to compensation for any loss or damage suffered. MLC 2006 Standard A5.2.1(8) is stronger: compensation shall be paid, and the burden of proof lies on the complainant. The claim is brought in the port State’s courts, and the remedy is covered in undue detention and compensation .

Refusal of access and banning

A banning order bars a named ship from every port of a regime. It is the regional form of the entry power in UNCLOS Article 211(3), and A.1206(34) paragraph 4.1.2 requires a Party that denies entry to give the master and the flag State its reasons.

In the Paris MoU, under section 4 of the Memorandum, a ship flying a grey-listed flag is refused access after more than two detentions in the preceding 24 months, and a black-listed flag after more than two in 36 months. The first order is lifted after 3 months, the second after 12, and the third after 24 months only on four conditions, otherwise it is permanent; any detention after a third order is permanent. The Paris MoU issued 19 refusal-of-access orders in 2025, against 15 in 2024. Changing the flag does not lift a ban. The mechanism is at refusal of access and banning .

The Tokyo MoU publishes an under-performing ships list, of ships detained three or more times in 12 months, rather than banning them outright. Its 2025 list carried 222 listings covering 52 ships. The Tokyo Committee’s September 2026 meeting discussed national legislation to bar certain ships from ports; nothing has been adopted at regional level.

The regional regimes

IMO counts nine regional PSC regimes: eight memoranda of understanding and one Agreement. IMO resolution A.682(17), Regional co-operation in the control of ships and discharges, adopted on 6 November 1991, invited States to form them. The United States Coast Guard maintains its own programme outside the regional system. A memorandum is an administrative arrangement between maritime Authorities, not a treaty; the binding power stays in the conventions and national law.

Origin: the Hague Memorandum and the Paris MoU

The first regional arrangement was the Hague Memorandum on maintenance standards in merchant ships, signed on 2 March 1978. The Amoco Cadiz grounding off Brittany later that month pushed European governments toward a wider safety and pollution regime. The Paris Memorandum of Understanding on Port State Control was signed on 26 January 1982, took effect on 1 July 1982, and superseded the Hague Memorandum under its section 9.3.

Regime comparison

The table below is Shipping-Wiki.com’s comparison, compiled from each regime’s own Memorandum text, website or latest annual report. Member counts are given only where the regime’s own document states them.

Membership overlaps. Cyprus, Malta and Croatia belong to both the Paris and Mediterranean MoUs, Canada to both the Paris and Tokyo MoUs, and the Russian Federation to the Tokyo and Black Sea MoUs alongside its suspended Paris membership. The Tokyo MoU’s observers include the other eight regimes, IMO, ILO and the US Coast Guard. An overview of the smaller regimes is at regional port State control MoUs .

What the instrument lists do not share

The regimes do not inspect against identical lists. The Paris MoU’s section 2.1 lists 15 relevant instruments and includes the Hong Kong Convention 2009 and the Nairobi Wreck Removal Convention. The Tokyo MoU’s section 2.1 also lists 15, but includes ILO Convention 147 and the 1978 SOLAS Protocol and omits both the Hong Kong and Nairobi conventions. A ship trading Europe to Asia meets two different scopes on the same voyage, and the inspection record in each region reflects only that region’s list.

Inspection volume

The two largest regimes carried out 52,020 initial inspections between them in 2025. The Paris MoU recorded 16,474 inspections, 668 detentions and a detention rate of 4.18 percent, against 16,509 inspections, 666 detentions and 4.03 percent in 2024. The Tokyo MoU recorded 35,546 initial inspections, 1,255 detentions on ships of 73 flags and a rate of 3.53 percent, covering 30,046 individual ships. The Mediterranean MoU’s 2024 annual report gives 5,993 inspections and 196 detentions for that year.

The Tokyo series shows how far the pandemic depressed the figures: inspections fell from 31,372 in 2019 to 19,416 in 2020, a drop of 38 percent, and did not regain the 2019 level until 2024.

The United States Coast Guard

The United States is outside the memoranda. IMO lists the US Coast Guard as maintaining its own PSC regime, and the Coast Guard sits as an observer Authority in the Tokyo MoU. It applies its own targeting matrix and runs the QUALSHIP 21 incentive programme for well-performing ships and flags. Both are national programmes and are not set by the IMO procedures; they are treated in USCG port State control .

The EU overlay

In the European Union, port State control is binding law rather than an administrative commitment. Directive 2009/16/EC on port State control, adopted on 23 April 2009, obliges EU coastal Member States to run the Paris MoU regime and gives the targeting, expanded inspection and banning rules legal force. The European Maritime Safety Agency hosts the THETIS database in Lisbon. The overlay is covered in full in the EU port State control Directive .

Directive (EU) 2024/3099 of 27 November 2024 amends the 2009 Directive, with transposition due by 6 July 2027. The main changes:

• A new Article 16 on refusal of access. A ship on the low performance list is refused access after more than two detentions in the preceding 36 months, and a ship on the high or medium list after more than two in 24 months. The first order is lifted after 3 months, the second after 12, the third may be lifted after 24 months on four conditions, otherwise the ban is permanent.
• Fishing vessels under 24 m in length, measured under the Cape Town Agreement of 2012, are excluded, and the recitals set out an optional PSC module for fishing vessels of 24 m and over (see PSC for fishing vessels ).
• The Hong Kong Convention is added to the scope.
• Amended Article 14 on expanded inspection, for high-risk ships and for older ships of the risk types where overriding or unexpected factors arise.

The Paris MoU’s Committee, at PSCC59 in Glasgow from 18 to 22 May 2026, aligned the Memorandum with the amended Directive from 6 July 2027, including changes to the flag and RO calculations and new environmental parameters in the ship risk profile.

Performance lists for flags, recognized organizations and companies

PSC data feeds back into the reputation of the flag, the RO and the company, and through the risk profile into how often their ships are boarded. That feedback loop is the main commercial lever the regime has.

The Paris MoU publishes a White, Grey and Black list of flags each year from three years of data, using a binomial method with an expected detention probability of 7 percent and a minimum of 30 inspections. The 2025 list, on 2023 to 2025 data and valid from 1 July 2026 to 6 July 2027, has 40 White, 19 Grey and 10 Black flags; the Black list’s very high risk band is Comoros, Tanzania and Cameroon. The Tokyo MoU’s list valid from 1 July 2026 to 30 June 2027 ranks 66 flags: 32 High, 19 Medium and 15 Low performance. The lists are explained in the Paris MoU White, Grey and Black list .

Recognized organizations are rated on the same method with a minimum of 60 inspections; the Paris MoU’s 2025 table covers 31 ROs and the Tokyo MoU’s 30. Company performance is calculated from deficiency and detention indices against the regional average, with ISM deficiencies weighted at 5 points in the Paris method against 1 for other deficiencies. A refusal of access anywhere in a company’s fleet within 36 months makes its Paris detention index above average. The Tokyo list marks Sint Maarten as a fraudulent registry by reference to IMO Circular Letter No.5019 of 20 May 2025 (see fraudulent ship registration ).

Concentrated inspection campaigns

A concentrated inspection campaign (CIC) is a three-month focus on one area of compliance, run alongside the normal inspection with a standard questionnaire. The Paris and Tokyo MoUs increasingly run them jointly, and a deficiency found in a CIC is handled under the normal detention rules.

The 2026 campaign tests the Cargo Securing Manual against the lashings actually fitted. The campaign series is at concentrated inspection campaign .

Environmental and energy-efficiency checks

The environmental scope of PSC has grown with MARPOL. A.1206(34) Appendix 18 carries the PSC guidance for MARPOL Annex VI , and Appendix 2 lists the Annex VI detainable items.

The detainable item is the missing document, not a poor rating. A ship rated D or E for CII is not detained for the rating; it is required by MARPOL Annex VI to have a corrective action plan in its SEEMP, which is a matter for the flag State and the RO (see CII corrective action plan ).

On sulphur, MEPC.1/Circ.881 of 21 May 2019 is the IMO guidance on the contingency measures a port State may accept where a ship has non-compliant fuel on board, and the FONAR and bunker delivery note set the documentary record the PSC officer reads. The IMO 2020 sulphur cap is the limit behind both.

Ballast water is checked under BWM Article 9: the International Ballast Water Management Certificate, the Ballast Water Management Plan, the record book and, where clear grounds exist, the treatment system itself (see ballast water management systems ). The Tokyo MoU’s 2025 BWM campaign is the most recent regional sweep of that scope.

EU regional measures, including the EU ETS , EU MRV and FuelEU Maritime , carry their own enforcement under EU law, and their document checks in EU ports sit outside the IMO procedures.

Security and cyber checks

Security entered PSC through SOLAS regulation XI-2/9, which allows a port State to require security information before entry and to inspect, delay, detain or expel a ship that does not comply with SOLAS Chapter XI-2 or the ISPS Code. The 2025 procedures added Appendix 20 to give PSC officers guidance on security aspects.

Cyber risk enters through the ISM Code, not through a separate PSC power. MSC.428(98), adopted on 16 June 2017, encourages Administrations to ensure that cyber risks are appropriately addressed in safety management systems no later than the first annual verification of the company’s Document of Compliance after 1 January 2021. The guidance is MSC-FAL.1/Circ.3/Rev.3 of 4 April 2025. A PSC officer looks for cyber risk in the safety management system the same way as for any other identified risk; the technical background is at maritime cyber security .

PSC officers: qualification and independence

A PSC officer is an official of the port State Administration, responsible exclusively to that Party (A.1206(34) paragraph 1.7.8). Paragraph 1.9.1 calls for an experienced officer qualified as a flag State surveyor, and paragraph 1.9.2 requires the ability to communicate in English with key crew.

For operational inspections under SOLAS XI-1/4 and the equivalent MARPOL provisions, paragraph 1.9.5 expects a master or chief engineer with appropriate seagoing experience, a recognized maritime qualification combined with specialized training, or an officer of the Administration with equivalent competence. Paragraph 1.8.3 bars a PSC officer from being employed by, or working on behalf of, a recognized organization or classification society. The Code of good practice in Appendix 1 (MSC-MEPC.4/Circ.2) sets the standards of integrity, professionalism and transparency expected at the gangway. The role is covered in port State control officer .

A.1206(34) paragraph 2.5.3 caps the officer’s reach: control is not to impose requirements in excess of those imposed on the port State’s own ships.

Relationship to flag State, class and the IMO audit

PSC sits at the end of a chain of responsibility, and its findings are read back up the chain. The flag State issues or authorizes the statutory certificates; the RO, usually a classification society member of IACS, surveys and certifies on its behalf; the company runs the ship under the ISM Code; and the port State checks the outcome at random calls.

A detention notified to the RO under paragraph 4.1.3 is a finding against the RO’s work as well as the ship’s, and it lowers the RO’s regional performance rating. The flag State’s own performance is audited under the IMO Member State Audit Scheme , made mandatory through SOLAS Chapter XIII , and Paris MoU low-risk status requires confirmation that the flag has been audited. The links between the layers explain why a detention can raise inspection frequency for every other ship under the same flag or with the same company.

Commercial consequences of a detention

A detention costs more than the repair. The Paris MoU text section 3.11 places the inspection costs of a detained ship on the owner or operator, and the time lost falls on whoever bears it under the charter. Many time charter off-hire clauses list detention for the ship’s own deficiencies as an off-hire event; the wording is the charter’s, not the PSC regime’s, and is discussed at off-hire and performance claims and charter parties overview .

Commercial vetting reads the same record. Oil majors’ SIRE inspections and the wider vessel vetting process are commercial programmes with no legal standing at the gangway, but a recent detention is a standard screening question, and the PSC record is public. The Paris MoU’s THETIS results are published on Equasis , and the Tokyo MoU sends its data to Equasis and to the IMO GISIS PSC module. P&I clubs and hull insurers also see the record when they assess a ship.

Limitations

This article states the IMO procedures as adopted in A.1206(34) on 3 December 2025 and the Paris and Tokyo regimes as published in their current Memorandum texts and 2025 annual reports. Each regime amends its Memorandum annually, so risk weightings, windows and list thresholds change, and the regime’s current text governs.

The national legal basis for detention, appeal and compensation differs between port States, and the IMO procedures are recommendatory: a ship’s rights in a given port depend on that State’s implementing law. Member counts for the Caribbean MoU are not given because its published list does not distinguish full members. US Coast Guard targeting criteria, QUALSHIP 21 eligibility and US inspection statistics are not stated here; the US programme is national and is documented by the Coast Guard. Directive (EU) 2024/3099 applies through national transposition by 6 July 2027, and until then the 2009 text governs in each Member State.

The statistics are annual figures from each regime’s own report and are not comparable on a like-for-like basis: the regimes count inspections, ships and detentions to different rules and inspect against different instrument lists.

Related Articles

• Paris MoU : the European and North Atlantic regime, its ship risk profile and banning rules
• Tokyo MoU : the Asia-Pacific regime, its New Inspection Regime and flag list
• IMO Procedures for Port State Control : resolution A.1206(34) and its lineage
• Regional port State control MoUs : the smaller regimes compared
• EU port State control Directive : Directive 2009/16/EC and its 2024 amendment
• USCG port State control : the US national programme
• MLC port State control : labour inspections under Regulation 5.2.1
• PSC detention review : the regional review panels
• PSC deficiency codes : how deficiencies are coded and actioned
• Port State control officer : qualification and powers
• Flag State and flag of convenience : the primary responsibility PSC supplements
• Classification society : the RO whose work a detention reflects on
• ISM Code : the safety management system PSC checks through SOLAS IX/6.2
• UNCLOS overview for shipping : Articles 211, 218, 219 and 226