Built for the people who dread the boarding: owners, operators, technical managers and the charterers who screen a ship before fixing it. A Port State Control detention costs days and reputation, and whether your ship gets boarded — and whether a deficiency becomes a detention — turns on a risk-scoring system and a deficiency-code list scattered across MoU circulars and class bulletins. We assembled how PSC targets ships, what inspectors check, and what turns a finding into a detention, into one place.
Screening a counterparty's ship? A vessel's flag, class and detention history are exactly the signals the rynda fleet tools and vessel identity surface.
📖 See also: Vessel identity — IMO vs MMSI · Ship types & sizes · CII, EEXI & EEDI ratings
Contents
- At a glance
- What Port State Control is and the MoU map
- The Ship Risk Profile — how you get targeted
- The White, Grey and Black flag lists
- Inspection types and windows
- Deficiencies and detention
- Concentrated Inspection Campaigns
- How to lower your risk
- For screeners and developers
- FAQ
- References
At a glance
The short version, if you read nothing else:
- Port State Control (PSC) is the inspection of foreign ships in a country's ports to check compliance with international conventions — SOLAS (safety of life at sea), MARPOL (pollution prevention), MLC (the Maritime Labour Convention — crew welfare and working conditions), Load Line, and STCW (the crew training and certification standard). It's the safety net that catches substandard ships the flag state missed.
- Inspections are coordinated by regional MoUs (Memoranda of Understanding — regional agreements between maritime authorities to inspect ships to a common standard) — Paris (Europe/North Atlantic), Tokyo (Asia-Pacific), plus the US Coast Guard and others — each running a shared database and a targeting system.
- You don't get inspected at random. Every ship carries a Ship Risk Profile (SRP) built from six factors — ship type, age, flag performance, classification society (RO) performance, company performance, and its deficiency/detention history over a rolling 36 months.
- The profile sets the inspection window: High Risk ships are due every 5–8 months, Standard every 10–18, Low Risk every 24–36.
- A deficiency is a finding to correct; a detention stops the ship from sailing until serious deficiencies are fixed. Detentions are public and feed back into the risk profile — a bad record compounds.
- The regional detention rate sits around 3–4 % of inspections and has held broadly steady in recent years — the enforcement bar is high, and ISM (management-system) failures are an increasingly common ground.
This is a practical reference, not compliance advice. The controlling texts are the IMO/ILO conventions and each MoU's procedures; confirm against the current MoU manual and your flag/class guidance.
What Port State Control is and the MoU map
Flag states are supposed to police their own ships, but many (especially open registries) delegate or under-enforce — so port states inspect visiting foreign ships as a backstop. PSC officers board and verify certificates, condition and operation against the major conventions, and can require fixes or detain the ship.
It's coordinated regionally so a ship isn't boarded in every port:
| MoU / authority | Region |
|---|---|
| Paris MoU | Europe + North Atlantic (27 authorities) |
| Tokyo MoU | Asia-Pacific (~21 authorities) |
| US Coast Guard | United States (its own regime) |
| Others | Viña del Mar (Latin America), Caribbean, Mediterranean, Indian Ocean, Abuja (W. Africa), Black Sea, Riyadh (Gulf) |
Each MoU shares a central database of inspections and detentions, so a ship's record follows it between member ports.
The Ship Risk Profile — how you get targeted
The New Inspection Regime (NIR) scores every ship into High / Standard / Low Risk from six weighted factors:
| Factor | What raises the risk |
|---|---|
| Ship type | Higher-risk types (e.g. bulk carriers, oil/chem/gas tankers, passenger ships) |
| Ship age | Over 12 years carries the heaviest weighting |
| Flag | A Grey/Black-list flag (see below), or one that skips the voluntary IMO audit |
| Recognised Organisation (RO) | A classification society with poor PSC performance |
| Company | The fleet-wide detention/deficiency record of the ISM Document of Compliance (DoC) holder — the company certified under the International Safety Management Code to operate the ship |
| History | The ship's own deficiencies and detentions over the last 36 months |
The last two are the ones you control operationally: a clean 36-month record and a company/DoC-holder with a good fleet record pull a ship toward Low Risk and far fewer boardings. A single detention pushes the other way — and it compounds, because history feeds the score.
The White, Grey and Black flag lists
Each MoU publishes an annual performance ranking of flag states based on their ships' inspection and detention record:
- White list — consistently low detention; good performers. Ships on white-list flags score better and are inspected less.
- Grey list — middling performance.
- Black list — high detention rates; ships on black-list flags are targeted harder and can face banning after repeated detentions.
The flag a ship flies is therefore a real risk input, not just a registry choice — which is why an open registry's list position matters to owners and to anyone screening a ship.
Inspection types and windows
The risk profile sets how often a ship is due and how deep the inspection goes:
| Risk band | Inspection window |
|---|---|
| High Risk | every 5–8 months |
| Standard Risk | every 10–18 months |
| Low Risk | every 24–36 months |
Inspection depth escalates:
- Initial — check certificates and the ship's overall condition.
- More Detailed — triggered by "clear grounds" (missing/invalid certificates, visibly poor condition, a report). The officer looks into the systems the clear grounds point to.
- Expanded — mandatory for high-risk ships and certain types/ages; a deep, system-by-system inspection.
"Clear grounds" is the trigger phrase: a torn-up certificate, a reported defect, or an obviously ill-maintained ship converts a routine boarding into a detailed one.
Deficiencies and detention
- Deficiency — a finding that doesn't meet a convention. It's coded (the MoU uses a standard deficiency-code list — e.g. fire safety, life-saving appliances, ISM, MARPOL, structural, MLC working/living conditions) and recorded with an action code (rectify before departure, within 14 days, at next port…).
- Detention — a ship is detained when deficiencies are serious enough that it's unsafe to sail; it can't leave until they're corrected and re-verified. Detentions are public, feed the ship's risk history, and hit the flag/RO/company records too.
- Detainable items are the serious ones — for example inoperable life-saving or fire-fighting equipment, an unsafe structure, a serious ISM (safety-management) failure, oily-water separator tampering, or MLC breaches on crew welfare. The ISM Code failures are increasingly common detention grounds because they point to a systemic management problem, not a one-off defect.
The detention rate across the major MoUs sits around 3–4 % of inspections and has held broadly steady year on year — a high bar, with ISM (safety-management) failures a growing share of the grounds.
Concentrated Inspection Campaigns
Each year the MoUs run a Concentrated Inspection Campaign (CIC) — a few months where inspectors focus on one theme across every boarding, using a set questionnaire. Recent themes have covered areas like fire safety, crew welfare (MLC), STCW/rest hours, and cargo securing (the 2026 Paris/Tokyo focus). If a CIC is running, expect that topic to be examined in depth on top of the normal inspection — prepare the relevant documentation and equipment in advance.
How to lower your risk
- Keep a clean 36-month record — history is a scored factor; every avoided deficiency compounds toward Low Risk and fewer boardings.
- Mind the company and flag you keep — a DoC-holder with a poor fleet record and a Grey/Black-list flag both raise every one of your ships' scores.
- Treat ISM as the root — many detentions are dressed-up management failures; a strong safety-management system prevents the findings that trigger detention.
- Prepare for the live CIC — check the year's campaign topic and have the paperwork and equipment ready.
- Self-inspect before the officer does — the deficiencies PSC finds are the ones a good superintendent finds first.
For screeners and developers
- A ship's PSC record is a due-diligence signal. Flag list position, class (RO), and detention history over 36 months tell you a lot about a counterparty's ship before you fix it — alongside the durable identity (IMO number) you should key the record on.
- Join on the IMO number, not name or MMSI, so a ship's detention history survives a re-flag or sale (see vessel identity).
- The rynda fleet tools surface vessel identity, flag and status — the same inputs a risk profile is built from.
FAQ and common confusions
Q: What is Port State Control?
A: PSC is the inspection of foreign ships in a country's ports to verify they meet international conventions (SOLAS, MARPOL, MLC, Load Line, STCW). It's a backstop for when the flag state hasn't enforced the standards, run regionally through MoUs like Paris and Tokyo.
Q: How does PSC decide which ships to inspect?
A: By a Ship Risk Profile scored from six factors — ship type, age (>12 yrs weighs heaviest), flag performance, classification society, company record, and the ship's own 36-month deficiency/detention history — which sorts ships into High / Standard / Low Risk and sets the inspection window.
Q: What's the difference between a deficiency and a detention?
A: A deficiency is a finding to correct (with an action code and deadline). A detention means deficiencies are serious enough that the ship can't sail until they're fixed and re-verified. Detentions are public and worsen the ship's risk profile.
Q: How often will my ship be inspected?
A: High Risk ships are due every 5–8 months, Standard every 10–18, Low Risk every 24–36 — so a clean record and a good flag/company genuinely cut the number of boardings.
Q: What are the White, Grey and Black lists?
A: Annual MoU rankings of flag states by their ships' detention performance. White = good (fewer inspections), Grey = middling, Black = poor (harder targeting, possible banning). The flag you fly is a real risk input.
Q: What most often causes a detention?
A: Serious safety items — inoperable life-saving/fire-fighting equipment, unsafe structure, oily-water-separator issues, MLC crew-welfare breaches — and increasingly ISM (safety-management) failures, because they signal a systemic problem rather than a one-off defect.
Q: What is a Concentrated Inspection Campaign?
A: A yearly period where PSC focuses on one theme (e.g. cargo securing for 2026) across every boarding using a set questionnaire. If one is running, that topic gets extra scrutiny — prepare for it.
Q: Does a poor CII rating affect PSC?
A: Indirectly. A ship lacking a valid SEEMP Part III / Statement of Compliance can attract PSC attention, and a poor CII rating adds commercial and scrutiny pressure — though CII itself isn't a PSC detention item.
References
- Paris MoU and Tokyo MoU — the New Inspection Regime, Ship Risk Profile, the White/Grey/Black lists, deficiency/action codes and the annual CIC.
- IMO Resolution A.1155(32) (Procedures for Port State Control) and the underlying conventions (SOLAS, MARPOL, MLC 2006, Load Line, STCW).
- US Coast Guard PSC — the separate US regime and targeting matrix.
- Class-society and P&I PSC preparation guidance (Lloyd's Register, DNV, ClassNK, the P&I clubs).
- rynda fleet tools and vessel identity reference.
Document version
- 2026-07 — first public version. How PSC targets, inspects and detains ships — the Ship Risk Profile, flag lists, inspection windows, deficiencies/detention and the CIC — in one frame. MoU procedures and campaign themes change yearly; confirm the current manual.