A PSC deficiency code is a five-digit number that identifies exactly what an inspector found wrong, and each one is paired with an action code that says what must happen next and by when. Reading the two together tells you how serious a finding is: code 17 means fix it before sailing, detention means the officer comes back to check.
What is a PSC deficiency code?
Every deficiency a Port State Control officer records on the inspection report (Form B) carries a standard five-digit code identifying the defective item. The codes exist so that a finding in Rotterdam means the same thing as a finding in Singapore: they feed the regional inspection databases (THETIS in the Paris MoU region), the annual statistics, and the risk calculations that decide how often a ship gets boarded. Because the deficiency history flows into targeting, each coded finding has a cost beyond its deadline; the mechanics are covered in how the Paris MoU Ship Risk Profile works.
The Paris MoU and Tokyo MoU lists are harmonized: the same areas, the same numbering, with small regional differences at the edges. If you have just been handed a Form B, the code tells you what the officer thinks is broken. The action code next to it tells you how much trouble you are in.
How do the five-digit deficiency codes work?
The code is built in three layers. The first two digits name the main area, the third digit narrows it to a sub-group, and the full five digits point at a specific defective item. Take 01101: area 01 (certificates and documentation), sub-group 011 (ship certificates), item 01101 (Cargo Ship Safety Equipment Certificate). Or 15150, the ISM code deficiency, which has a whole enforcement machinery of its own.
The main areas in the current Paris MoU list:
| Area | Covers |
|---|---|
| 01 | Certificates and documentation (ship, crew, documents) |
| 02 | Structural condition |
| 03 | Water and weathertight condition |
| 04 | Emergency systems |
| 05 | Radio communication |
| 06 | Cargo operations including equipment |
| 07 | Fire safety |
| 08 | Alarms |
| 10 | Safety of navigation |
| 11 | Life saving appliances |
| 12 | Dangerous goods |
| 13 | Propulsion and auxiliary machinery |
| 14 | Pollution prevention (MARPOL Annexes I-VI, anti-fouling, ballast water) |
| 15 | ISM |
| 16 | ISPS |
| 18 | MLC, 2006 |
| 99 | Other |
Two quirks worth knowing. There is no area 17, so "code 17" always refers to an action code, never a deficiency area. And the Tokyo MoU list keeps a full area 09 for working and living conditions where the Paris list handles most of that under 18 (MLC, 2006).
What are the action codes (10, 15, 16, 17, 30, 99)?
The action code is the deadline attached to a deficiency. The core set, with the official Paris MoU meanings:
| Action code | Meaning | In practice |
|---|---|---|
| 10 | Deficiency rectified | Fixed and verified by the officer during the inspection itself |
| 15 | To be rectified at the next port | Cannot be fixed before departure; the next port follows up |
| 16 | To be rectified within 14 days | Not serious enough to hold for; master fixes it within the limit |
| 17 | To be rectified before departure | Must be fixed before sailing, but no detention and no re-verification |
| 19 | Safety management audit required before departure | Used only for a detainable ISM deficiency (15150) |
| 21 | ISM corrective action by the company within 3 months | Also reserved for 15150 |
| 30 | Detainable deficiency (Tokyo MoU) | The finding is grounds for detention |
| 46 | To be rectified at agreed repair port | A detainable deficiency the officer allows the ship to sail to a repair port with |
| 99 | Master instructed to... | A specific written instruction not covered by the standard codes |
One clarification the industry summaries usually skip: the current Paris MoU guidelines (PSCC59/2026/03, June 2026) no longer carry a numeric code 30. In Paris MoU records, a detainable finding is marked with a "grounds for detention" flag against the deficiency, alongside codes such as 46 for an agreed repair port. The Tokyo MoU still uses action code 30 for detainable deficiencies, and its reports say so explicitly. The meaning is identical either way, which is why "code 30" survives as shorthand across both regions.
What is the difference between code 17 and code 30?
Code 17 means the deficiency must be rectified before the ship sails but is not serious enough to warrant detention. Code 30 marks a detainable deficiency: the ship is held until the deficiency is fixed and an officer has come back on board to verify it.
The dividing line is re-verification. Under code 17, rectification is left to the master's responsibility and no PSCO verification is required at that port call; the ship sails on trust, and the fix is checked against the record at the next inspection. A detainable deficiency fails exactly that test: the Paris MoU criterion for detention is that the deficiencies are sufficiently serious to merit a PSCO returning to the ship to be satisfied they have been rectified before the ship sails.
The practical consequences differ sharply. A code 17 costs the crew a repair before departure. A detention stops the ship, is published, notifies the flag State, raises the Ship Risk Profile, and counts toward a possible ban; the full bill is laid out in what a PSC detention costs. If a Form B is sitting on your desk, the first read is simple: find anything marked detainable, then anything with code 17, then the dated deadlines.
What makes a deficiency detainable?
The test in IMO Resolution A.1206(34) is professional judgement against one question: can the ship proceed to sea without unreasonable danger to safety, health or the environment, considering the intended voyage? Two criteria follow. A ship unsafe to proceed to sea is detained at the first inspection regardless of how long it will stay in port, and a ship is detained when the deficiencies are serious enough to require an officer to return and verify rectification before departure.
The Paris MoU guidance turns that into a list of assessments: whether the ship has valid documents and the crew required by the safe manning document, and whether it can safely navigate, handle cargo, operate the engine room, fight fires, abandon ship, prevent pollution, maintain stability and watertight integrity, and communicate in distress. A negative answer on any of these makes detention strongly considered. Notably, a combination of deficiencies that are individually less serious can also warrant detention, and a serious failure in implementing the ISM Code is a ground for detention in itself. That is why five small findings in one area worry an experienced master more than one large one.
Where is the official Paris MoU code list?
The authoritative list is "Overview of Deficiency Codes", published on parismou.org and last revised on 1 July 2025; the action codes live in a separate document, "Guidelines on detention and action taken" (PSCC59/2026/03, published June 2026). The Tokyo MoU publishes its own list, updated December 2025, on tokyo-mou.org. All three are free PDFs, and the exact URLs are in the sources below. Codes get added and retired at revisions, so check the current list rather than a reproduction on a third-party site.
Knowing the codes is the reactive half. The proactive half is finding the items behind them before an officer does, which is what preparing for a PSC inspection covers, and what the whole boarding sequence looks like from the gangway is in what happens during a PSC inspection.
One honest limit: no code list tells you how an individual officer will weigh what they see. The codes standardize the record, not the judgement. What they reliably tell you is what was found, what deadline applies, and whether the ship moves; on a fresh Form B, that is the information that matters first.