Vessel inspections, explained.
Port State Control. MOUs. Detentions vs deficiencies. Why your container's vessel can sit at berth for three extra days, and how to spot the risk before it ships.
You don't think about ship inspections. Until the ship carrying your container gets one, fails it, and now everything on board is delayed by 96 hours while a Korean maritime officer in a fluorescent vest argues about the lifeboat release mechanism.
This is more common than most shippers realise. Roughly 1 in 5 vessels inspected under Port State Control regimes turns up at least one deficiency. Roughly 1 in 35 gets detained — held at berth until specific issues are fixed. If you're moving freight, the question isn't whether you'll be affected. It's how soon you find out.
What's a Port State Control inspection?
Every ship at sea operates under the flag of some country — that country is the flag state and is technically responsible for the vessel's compliance with international maritime rules (SOLAS, MARPOL, MLC, STCW, etc.). In practice, flag states vary wildly in how strictly they enforce those rules. Some are rigorous. Some are essentially mailboxes.
Port State Control (PSC) is the international system by which the country where a ship is currently visiting — the port state — also gets to inspect it. The idea is that if Panama doesn't actually check that the lifeboats work, the inspector in Long Beach can.
PSC inspections happen routinely. The inspector boards the vessel, reviews documents (certificates, crew papers, log books), then physically inspects the ship — engine room, bridge, lifesaving equipment, navigation gear, MARPOL pollution prevention systems. The visit typically takes 4–10 hours.
The MOU system
Countries coordinate through regional Memoranda of Understanding so the same ship isn't inspected six times in six ports. The biggest blocs:
- Paris MOU — 27 European nations + Canada
- Tokyo MOU — most of Asia-Pacific
- USCG — the United States (not technically an MOU, but operates similarly)
- Indian Ocean MOU, Mediterranean MOU, Black Sea MOU, Viña del Mar Agreement (Latin America), Riyadh MOU (Gulf), Abuja MOU (West & Central Africa)
Each MOU publishes performance lists ranking flag states (whitelist / greylist / blacklist) and operators (companies). A vessel flagged by a blacklisted state operated by a poor-performing company is far more likely to be inspected on arrival — and inspected hard.
Deficiency vs detention
This is the distinction that matters for your shipment.
| Outcome | Meaning | Impact on your container |
|---|---|---|
| No issues | The inspector found nothing actionable. | None. Ship sails on schedule. |
| Deficiencies | Issues identified but not severe enough to detain. Must be rectified within a set time, sometimes at the next port. | Usually none — the ship sails. Occasionally a half-day delay for paperwork. |
| Detention | One or more serious deficiencies. Ship is barred from sailing until fixed. | 2–14 days of delay typical. Cargo waits. Demurrage clock may start. Onward connections miss. |
What causes detentions?
The 2025 Paris MOU annual report breakdown of top deficiency categories:
- Fire safety (~17%)
- Safety of navigation (~12%)
- ISM / safety management (~10%)
- Lifesaving appliances (~8%)
- Working & living conditions (~8%)
- MARPOL pollution prevention (~7%)
Most detentions stem from multiple minor issues that collectively suggest the vessel is being poorly managed — not from a single dramatic problem.
Old + flag-of-convenience + recent operator change = inspection risk.
A 20-year-old container ship, freshly re-flagged to a blacklisted state, recently sold to an unknown operator, is the highest-risk profile. If your container is on one of those, build extra schedule buffer.
Classification societies
The other inspection layer is the classification society — a private body that certifies the vessel meets construction and maintenance standards. The big ones: DNV (Norway), Lloyd's Register (UK), ABS (USA), Bureau Veritas (France), ClassNK (Japan), RINA (Italy), KR (Korea), CCS (China). Together they classify ~95% of the world tonnage.
A class society does periodic surveys (annual, intermediate, special). A vessel that loses its class is uninsurable and effectively unusable. You don't see this routinely — it's a slower, deeper inspection regime than PSC — but a vessel mid-class-renewal can have surprising drydock periods.
How to check a vessel before it carries your freight
Public tools:
- Paris MOU "ParisMOU.org" inspection database — searchable by IMO number, shows past inspections + deficiencies + detentions for the last 3 years.
- Tokyo MOU APCIS — same for the Asia-Pacific region.
- USCG PSIX — US-specific inspection history.
- Equasis — free, aggregates flag, class, owner, operator, and recent inspections for any vessel by IMO.
For an active shipment, watch for sudden anchorage near a port state with a strict MOU regime; the typical pattern is "arrived → inspected → 24-hr deficiency window → sailed" or "arrived → inspected → detained → 3-14 day fix → released."
What Broadpath surfaces
We track inspection events as part of vessel intelligence:
- Last PSC inspection date, port, and outcome (none / deficiencies / detention)
- Flag state and class society
- Operator history — flag changes in the last 12 months are a signal
- Real-time alert when a vessel carrying one of your containers becomes anchored outside its scheduled port for >12 hours
None of this prevents a detention. It just means you find out three days before the carrier emails you to apologise.
Want a specific vessel's inspection record pulled? Email [email protected] with the IMO and we'll send you the latest Equasis + MOU summary.