Port State Control

Port State Control within the control system

Port State Control (PSC) is a State's right and duty to inspect foreign ships calling at its ports, to verify that the ship, crew and equipment comply with the standards of the international conventions to which that State is a party. It stems from the principle that, if the flag alone does not guarantee sufficient oversight, the port State is entitled to intervene, regardless of the ship's flag.

Origin and purpose

Modern PSC took shape after a series of serious accidents and cases of substandard ships escaping their own flag's controls. Cooperation between port States, formalised in regional Memoranda of Understanding (MoUs), was created to prevent a ship refused or detained in one port from simply moving to a less attentive nearby port (the phenomenon known as «port shopping»).

PSC within the control triangle

As already seen for technical management, it is essential to distinguish PSC from class and from vetting: PSC is a public, statutory and mandatory control; class is a technical control based on privately, contractually accepted rules; vetting is voluntary commercial due diligence that is nonetheless de facto necessary to operate in certain segments.

Table 1.1 — PSC compared with class and vetting.

Regional regimes: Paris MoU, Tokyo MoU, USCG

Module objectiveRecognise the structure and operational differences of major PSC regimes without assuming a single global database.

There is no single worldwide Port State Control: cooperating regional regimes exist, each with its own database, performance lists and targeting logic, while sharing the same underlying IMO convention framework. This module gives the map; the two that follow go deeper into the two settings a European fleet meets most often — the binding legal layer of the European Union and the autonomous United States regime.

Regional Port State Control regimes and the binding legal layer of the European Union.

The main regimes

Table 2.1 — Overview of the main regional PSC regimes.

Cooperation and data sharing

Regional regimes cooperate and exchange information through agreements, regional databases and shared systems such as IMO GISIS and EQUASIS. Integration is neither uniform nor invariably available in real time: THETIS and APCIS remain separate systems and, according to the Tokyo MoU Annual Report 2025, the direct APCIS–THETIS link is temporarily suspended. Official sources for the relevant regime should therefore be checked separately before a port call.

The European layer: from Directive 2009/16/EC to 2024/3099

Module objectiveDistinguish the Memorandum from the EU legal basis and place Directive (EU) 2024/3099 in its correct timeline.

The Paris MoU is an administrative agreement between maritime Authorities: it defines method, criteria and tools, but it is not a legally binding instrument. For European Union Member States, and for the EEA States that take part, the binding source is Directive 2009/16/EC, which adopts the Memorandum's framework and turns it into an obligation of domestic law — in Italy through Legislative Decree 53 of 24 March 2011. In practice the two texts coexist: the inspector applies the MoU method, but the legal basis of their power, and its limits, sit in the directive.

What the directive adds to the Memorandum

Table 3.1 — The Memorandum and the directive compared.

The 2024 revision: what changes and from when

Directive (EU) 2024/3099, adopted on 27 November 2024 and in force since 5 January 2025, is the broadest revision since 2009. Member States must adopt and publish the necessary national provisions by 6 July 2027: until the transposing rules apply, the revised criteria should not be described as already operational on a uniform basis across all Member States. 6 July 2027 is the directive's transposition deadline, not the expiry date of the performance lists.

Banning compared: the Memorandum thresholds and those of Directive (EU) 2024/3099.

Table 3.2 — The main changes introduced by Directive (EU) 2024/3099.

THETIS and EMSA: who actually calculates the profile

THETIS is both a database and an operational tool: it records inspection reports and makes them available, manages the workflow from port call to inspection and follow-up, and recalculates Ship Risk Profile and priority daily from the available data. It is the European information system run by EMSA (the European Maritime Safety Agency): it assigns Priority I or II and distributes the annual inspection commitment among Member States. When a PSCO opens a ship's record, they are reading the output of that calculation, not a personal assessment. Around the same core EMSA runs separate systems — THETIS-MRV for CO₂ emissions reporting and THETIS-EU for compliance checks under other Union legislation — which remain modules of the THETIS portfolio with their own legal purposes: they do not merge into a single ship file.

The United States regime: risk matrix and QUALSHIP 21

The United States belongs to no Memorandum: the United States Coast Guard exercises port State control through a system of its own, independent in its targeting criteria, its consequences and — above all — its incentives. Anyone operating transatlantic routes has to read two different grammars, not one translated.

How USCG targeting works

The US system does not use the NIR Ship Risk Profile. Selection rests on a matrix that weighs flag performance, recognized organization performance, ship management performance, the arrival information (type, age, certificates, hazardous conditions), the individual ship's history — deficiencies, detentions, control actions, casualties, violations, EQUASIS data — and any enrolment in the QUALSHIP 21 and E-Zero programmes.

Flags are classified on their three-year detention ratio: High Risk above 2.0%, Medium Risk between 1.0% and 2.0%; the Coast Guard targets flags above 1.0% that have recorded multiple detentions. Recognized organizations with a detention ratio above 2.0% are designated Priority I for approval purposes.

QUALSHIP 21 and E-Zero: the incentive, not just the penalty

What really sets the US regime apart is the reward for quality. QUALSHIP 21 recognises foreign ships of documented quality by reducing their inspection exposure, and its criteria operate on three levels that must all be satisfied together. The eligibility criteria in force are set out in Coast Guard Work Instruction CVC-WI-002(2).

Table 4.1 — QUALSHIP 21 eligibility criteria.

Within the programme, the E-Zero designation rewards environmental performance. It is reserved for ships with at least three consecutive years in QUALSHIP 21, with no break longer than 30 days, and requires: zero MARPOL detentions worldwide over the past three years; no environmental deficiencies in the US over the same period; no violation of Right Whale reporting or speed restriction rules, on a five-year lookback; and an installed USCG type-approved ballast water management system.

Table 4.2 — QUALSHIP 21 benefits.

The New Inspection Regime and the Ship Risk Profile

The New Inspection Regime (NIR), introduced by the Paris MoU in 2011 and subsequently adopted in similar forms by other regimes including the Tokyo MoU, replaced simplistic targeting based on fixed inspection percentages with a risk-based system: inspection resources are concentrated on ships statistically more likely to have deficiencies, while rewarding quality ships with longer intervals between inspections.

The Ship Risk Profile (SRP) factors

Ship Risk Profile parameters and weightings: a ship is an HRS at 5 points or more (Paris MoU, Annex 7, Table 1).

Table 5.1 — Ship Risk Profile parameters and weightings (Paris MoU, Annex 7, Table 1).

The sum of the weightings determines the category. A ship is a High Risk Ship (HRS) if it reaches 5 or more points. It is a Low Risk Ship (LRS) only if it meets every criterion in the low risk column and has had at least one inspection in the previous 36 months: a single missing criterion is enough to lose the status. In any other case it is a Standard Risk Ship (SRS). The profile is recalculated daily by the information system on the dynamic parameters — age, 36-month history, company performance — as well as after every inspection and whenever the applicable flag and RO performance tables change.

The three risk categories and inspection windows

Based on the resulting score, the ship is classified as a Low Risk Ship (LRS), Standard Risk Ship (SRS) or High Risk Ship (HRS). Each category determines a time window within which the ship must undergo a periodic inspection: the higher the risk, the narrower the window. The windows are 5–6 months for an HRS, 10–12 months for an SRS and 24–36 months for an LRS: from the first figure the ship may be inspected (Priority II), from the second it must be (Priority I).

Periodic inspection windows and selection priority by risk category (Paris MoU, Annex 8).

Overriding and unexpected factors: when the window no longer matters

The Memorandum distinguishes two families of events that can trigger an additional inspection outside the window, with different effects on priority: overriding factors oblige the Authority to inspect, while unexpected factors authorise it to do so, leaving the decision to the inspector's professional judgement.

Table 5.2 — Overriding and unexpected factors (Paris MoU, Annex 8, §§11-12).

The White, Grey and Black lists

Every year the Paris MoU publishes, in its annual report, the White, Grey and Black (WGB) list: a ranking of flag performance based on the number of inspections and detentions recorded over a rolling three-year period, for flags that exceed a minimum inspection threshold in that period.

2025 flag performance lists and the Black List risk bands (Paris MoU, PSCC 59).

The most recent data (Paris MoU)

According to the results for the 2023-2025 period, approved by the Paris MoU Committee at its 59th meeting, the new lists apply from 1 July 2026 to 30 June 2027. They comprise 40 flags on the White List, 19 on the Grey List and 10 on the Black List. The top positions for performance are held by the Cayman Islands, Sweden, Norway, Denmark and Japan, followed by Singapore, France, Finland, the Netherlands and Luxembourg. Among high-volume flags, Liberia recorded 6,319 inspections and 276 detentions over the three-year period (rank 29), the Marshall Islands 5,166 inspections and 167 detentions (rank 21), and Panama 5,731 inspections and 338 detentions (rank 36). An HRS becomes Priority II after five months and Priority I after six months from its last inspection in the region: HRS status does not in itself mean inspection at every port call.

The Black List is not a single block

For Ship Risk Profile purposes the Black List is itself divided into bands of increasing risk — Medium Risk, Medium-to-High Risk, High Risk, Very High Risk — and the distinction has a concrete effect: the three upper bands are worth 2 points in the profile calculation, the Medium Risk band 1. Two ships both flying a «black flag» can therefore end up in appreciably different targeting positions.

Recognized Organizations have a performance list too

The same annual report ranks Recognized Organizations with at least 60 inspections over the three-year period. In the 2023-2025 exercise, high performers include DNV (18,350 inspections, 26 detentions), Bureau Veritas (12,261 inspections, 31 detentions) and Lloyd's Register (11,729 inspections, 25 detentions); a single organisation, Hellas Naval Bureau of Shipping, is classed as low performance. The classification bears directly on the individual ship: a Low or Very Low RO adds 1 point to the Ship Risk Profile of every ship carrying its certificates.

Practical consequences of list position

Table 6.1 — Practical consequences of list position for an individual ship.

Before the inspection: notification and selection

Module objectiveManage pre-arrival notifications and selection logic before a call in the Paris MoU region.

A PSC inspection is almost never a random event: it results from a selection process based on the Ship Risk Profile, supplemented by external reports and advance notification obligations.

Notification obligations (ETA)

The Memorandum provides for two distinct messages, with different addressees and content.

• 72-hour message (72 ETA) — owed by ships eligible for an expanded inspection, that is HRS and risk ship types over 12 years old, bound for a port or anchorage in the region. It carries ship identification (mandatory IMO number), port of destination, ETA and ETD, planned duration of the call, for tankers the hull configuration and the condition, volume and nature of cargo and ballast, the operations planned in port, the statutory surveys and substantial maintenance work scheduled during the call, and the date of the last expanded inspection in the Paris MoU region.
• 24-hour message (24 ETA) — owed by every ship bound for a port or anchorage in the region, at least 24 hours before arrival; or on departure from the previous port if the passage takes less than 24 hours; or as soon as the information is available if the port of call is unknown or changes during the voyage. It carries ship identification, port of destination, ETA and ETD.

Failure to comply with the reporting obligations is not an overriding factor but an unexpected factor: it does not oblige the Authority to inspect, but authorises an additional visit at Priority II and keeps the ship eligible in subsequent ports.

Priority I and Priority II

Table 7.1 — Inspection and selection scheme (Paris MoU, Annex 8, Table 3).

Periodic and additional inspections count equally: after an additional inspection the window for the next periodic one restarts from zero. If a Priority II inspection is not carried out, the ship remains Priority II until the window closes, at which point it becomes Priority I.

External reporting sources

• Crew complaints, often relating to working conditions (MLC) or safety.
• Reports from agents, port pilots or terminal operators who notice visible anomalies.
• Information shared by other member States or other regional regimes.
• Reports of accidents, near-misses or pollution occurring near the port.

Inspection on board: types and conduct

Module objectiveDistinguish the category, type and possible extension of a PSC inspection and prepare the ship proportionately.

Understanding the different types of inspection and how the inspector conducts the visit helps the crew manage the event methodically, avoiding both excessive anxiety and underestimation.

Types of inspection

Table 8.1 — Types of PSC inspection (Paris MoU, Annex 9, Table 4).

How the visit actually unfolds

• Welcoming the inspector: identity verification and communicating the purpose of the visit to the Master.
• Document check: statutory and class certificates, DOC/SMC, logbooks, records.
• General inspection round: apparent condition of the hull, deck, engine room, accommodation.
• Targeted follow-up if clear grounds emerge: practical tests (e.g. steering gear test, fire drill).
• Interview with the crew, including on hours of rest and MLC conditions.
• Debrief with the Master: communication of identified deficiencies and their action codes.

Deficiencies and action codes

Module objectiveInterpret a deficiency, its action code and the criteria that may lead to detention.

Every deficiency found is assigned an action code that determines how it is handled: some must be rectified before departure, others within a set period, and the most serious result in detention. The codes are not left to the individual inspector's discretion: they are standardised by the Port State Control Committee instruction — in the version in force, PSCC59/2026/03 «Detention and Action Taken» — and the same coding is read by inspectors throughout the region and by charterers' due diligence systems. Being able to read them means knowing in advance what the ship will have to demonstrate, and by when.

From the deficiency to the action code: the three possible outcomes and their codes (PSCC59/2026/03, Annex 1).

The Paris MoU action taken codes

Action codes are not a descriptive label but a codified language: they fall into three families — action on the individual deficiency, action on the inspection, and reporting action — and they determine what happens to the ship after departure. The group that matters for day-to-day management is the first.

Table 9.1 — Deficiency action taken codes (Paris MoU, PSCC59/2026/03, Annex 1).

When a deficiency becomes grounds for detention

The decision to detain a ship does not come from counting deficiencies but from a structured assessment. The PSCO first checks two documentary preconditions and then twelve operational capabilities of the ship and its crew, all referred to the voyage about to begin.

Table 9.2 — Detention assessment criteria (Paris MoU, PSCC59/2026/03, §2.3.3).

If even one of these assessments is negative, taking into account all the deficiencies found, the ship is a strong candidate for detention. And the converse of the usual assumption also holds: a combination of individually less serious deficiencies may warrant detention if, taken together, they compromise one of these capabilities.

ISM deficiencies: the code 19 and code 21 mechanism

ISM deficiencies are recorded under a single defective item code, 15150, and they are the only ones that produce an automatic consequence for the company and not just for the ship. The PSCO uses them when establishing a link between the technical or operational deficiencies found and the implementation of the ISM Code.

• If that link indicates a failure or lack of effectiveness in implementation, but the deficiencies do not warrant detention, the ISM deficiency is given code 21: the company must take corrective action on the system within 3 months. Once the 3 months elapse, the still-open deficiency generates an unexpected factor and the ship becomes eligible for an additional inspection again.
• If the link indicates a serious failure, the ISM deficiency is a ground for detention and is given code 19: the flag Administration must carry out a safety management audit before the ship can depart. Once the audit is done, closure is recorded with code 21.

When the inspection is suspended

In exceptional circumstances the PSCO may suspend the inspection rather than complete it. The case provided for is one where all statutory certificates are missing, expired or invalid. Suspension does require that all of the following have been completed: the certificates and documents of Annex 10 checked; the overall condition of the ship and its equipment checked, including the crew's living and working conditions; rectification of outstanding deficiencies verified; a more detailed inspection in the areas where clear grounds are established; a more detailed inspection at random in other areas; operational controls carried out; and detainable deficiencies established in several areas.

Once all these conditions are met, the ship may be detained and the inspection suspended until the responsible parties — flag State and recognised organisation — have ensured that the ship complies with all the relevant Conventions. Suspension is not to be confused with halting an inspection for operational or safety reasons, for example overnight, which is simply continued later.

Most frequent deficiency areas

Recurring deficiency areas according to the Paris MoU 2025 annual report.

Fire safety and life-saving appliance deficiencies remain among the most frequent in absolute terms, but ISM Code-related deficiencies deserve particular attention: they signal not an isolated problem but a weakness in the management system, and tend to draw additional scrutiny to the company, not just the individual ship.

Detention and banning

Module objectiveReconstruct the triggers, duration and escalation of refusal of access under the Paris MoU.

Detention is the most serious measure a PSC inspection can impose short of a full access ban: the ship is held in port until the deficiencies that caused the detention have been rectified and verified.

When detention is triggered

A detention is ordered when the deficiencies found are such that the ship, crew or environment would be at risk if the ship departed in the condition found. It is not tied to a minimum number of deficiencies: even a single very serious deficiency (for example a critical steering gear failure) can justify a detention on its own.

Escalation towards banning

The refusal of access ladder: trigger, lifting periods and conditions (Paris MoU, Section 4.1).

Under the Paris MoU regime, refusal of access — a ban on calling at any port or anchorage in the region — is triggered when a ship has been detained more than twice in the region within a window that depends on its flag's list: 36 months for Black List flags, 24 months for Grey List flags. The detention threshold is therefore the same; what changes is how far back the history is examined, which is why a Black List flag stays exposed for longer. White List flags are not subject to banning for multiple detentions under the Memorandum — the European Union regime is different, and stricter (Module 03). The order takes effect as soon as the ship leaves the port or anchorage where it was issued.

Table 10.1 — Refusal of access escalation (Paris MoU, Section 4.1).

An individual port State may derogate from the ban only in the event of force majeure or overriding safety considerations, or to reduce or minimise the risk of pollution, and provided the owner, operator or master has implemented adequate measures to ensure safe entry.

Commercial and insurance consequences

• Immediate loss of chartering days (off-hire) during the detention.
• Direct, lasting impact on the Ship Risk Profile, with a reduced inspection window for the following 36 months.
• Visible flagging in due diligence systems used by charterers and vetting bodies (SIRE, RightShip).
• Possible increase in H&M and P&I insurance premiums and financing terms.
• In the most serious cases, a supplementary company audit by the flag or the classification society.

Concentrated Inspection Campaigns (CICs)

Module objectivePrepare ship and crew for a Concentrated Inspection Campaign using the official topic, questionnaire and campaign window.

In addition to ordinary inspections, regional regimes periodically conduct Concentrated Inspection Campaigns: targeted inspections on a specific theme, carried out during a defined period of the year, often in cooperation between multiple MoUs.

Joint Paris MoU / Tokyo MoU Concentrated Inspection Campaign themes, 2021 to 2026.

How a CIC works

Each campaign focuses on a theme chosen based on emerging risk trends or recent safety concerns. The Paris MoU and Tokyo MoU coordinate their themes and run joint campaigns, with a common pre-defined questionnaire the PSCO completes in addition to the normal inspection; the window is consistently 1 September – 30 November.

Table 11.1 — Joint Paris MoU / Tokyo MoU Concentrated Inspection Campaign themes.

Preparing the ship for a CIC

• Check the campaign theme announced by your relevant regime well in advance.
• Carry out a targeted internal audit on the thematic area, using logic similar to the pre-vetting seen in the Vetting course.
• Ensure theme-specific documentation is up to date and consistent with onboard practice.
• Train the crew on the theme with a brief practical refresher, not just theory.

Post-inspection management and appeals

Module objectiveManage closure, evidence, costs and appeal after an inspection or a detention.

Formal closure of the inspection does not mark the end of the vetting/PSC officer's work: post-inspection management — closing deficiencies, internal communication, any appeal — is often what determines the event's real impact on the ship and the company.

The deficiency closure process

• Formal recording of every deficiency in the company's management system, with an owner and a deadline.
• Corrective action on the cause, not just rectification of the symptom (the same CAPA logic seen in ISM management).
• Collecting closure evidence (photos, certificates, updated records) to present, if requested, at the next port of call or to the regime.
• Sharing the lesson learned with the rest of the fleet, to prevent the same deficiency elsewhere.

The cost of a detention falls on the owner

An aspect often overlooked in planning: where an inspection confirms or reveals deficiencies warranting detention, all costs relating to the inspections fall on the owner, the operator or their representative in the port State, and the same applies to the costs of inspections carried out under the banning procedures. Above all: the detention is not lifted until full payment has been made, or a sufficient guarantee given to cover it. It is therefore not a charge to be settled afterwards: it is a condition of sailing again.

The right of appeal

The owner, the operator or their representative has the right to appeal against a detention or refusal of access decision, and the Authority must properly inform the master of that right and of how to exercise it. There are, however, two limits worth knowing before the situation arises.

• An appeal does not suspend the measure. The Memorandum (§3.12) and Directive 2009/16/EC (Article 20) say so in the same terms: the ship remains detained, or excluded, while the appeal is examined. The lever for sailing again is rectification, not appeal.
• The burden of proof lies with the appellant. In any allegation of undue detention or delay the burden falls on the owner or operator. A credible appeal is built on technical evidence gathered during the inspection, not on a verbally expressed disagreement.

If the appeal succeeds and the measure is lifted or amended, the inspection database must be updated promptly and the published information corrected within twenty-four hours of the decision. This is worth actively checking: for as long as the incorrect record remains in the database, it continues to weigh on the ship's Ship Risk Profile for the following 36 months.

PSC KPIs and fleet management

Module objectiveBuild a PSC dashboard that distinguishes volume, severity, recurrence and future inspection workload.

As with vetting, Port State Control also generates valuable data for managing the whole fleet, if collected and analysed systematically rather than ship by ship.

The essential KPI dashboard

Table 13.1 — Company Port State Control KPI dashboard.

Emerging trends in Port State Control

Module objectiveSeparate PSC requirements already in force from evolving interoperability and future regulatory developments.

Like vetting, Port State Control is also evolving, driven by digitalisation, decarbonisation and growing harmonisation between different regional regimes.

Requirements already subject to verification

Documentation concerning EEXI, SEEMP and CII already forms part of the applicable MARPOL framework and may be checked through PSC under the instruments in force. This is not a future prospect: it is material an inspector can ask for today, alongside traditional safety and MARPOL checks.

Developments to monitor

Any new duties arising from a future IMO Net-Zero framework should be described only after adoption and entry into force, clearly separated from current requirements. Treating what is still under discussion as though it were in force is the quickest way to prepare the ship for the wrong thing.

Interoperability between regimes

Regimes cooperate, exchange data and conduct joint campaigns — the Paris and Tokyo MoUs already run joint CICs — but their databases remain distinct and operational links may be partial or temporarily unavailable. Cooperation narrows the room for «port shopping», it does not remove it, and each regime remains legally autonomous in its own decisions.