PSC Deficiency Codes Explained: Detainable vs Non-Detainable
A port state control finding arrives as two numbers, and crews routinely read only one of them. The first says what is wrong. The second says what it costs you — whether you sail tonight, whether somebody has to come back and look again, and how long the clock runs. This guide decodes both: how the code is built, what each action code obliges, where the line between detainable and non-detainable actually sits, and how to evidence a rectification so a finding closes instead of escalating.
PSC deficiency and action codes
One finding, two numbers, and only one of them decides whether you sail
Findings recorded with their codes, deadlines and evidence in one place
The deficiency code identifies the finding. It is a five-digit number in which the first two digits name the area and the remaining digits narrow it to the specific item — so 01 covers certificates and documents, 07 covers fire safety, 11 covers life-saving appliances, and so on across the regime. The complete list is published by the memoranda and runs to several hundred entries.
First two digits
The area. This is the part worth knowing by heart, because it is how deficiencies group when you look at a fleet rather than a ship, and how campaigns and trends are reported.
Remaining digits
The specific item within that area. Useful for closing the finding precisely and for matching it against the same item at the next inspection.
What it does not carry
Any indication of severity. Two findings with codes in the same area can be a note and a detention. The deficiency code never tells you which.
This is the single most common misreading on board: treating the deficiency code as a measure of seriousness. It is a label for a location in the regulations, not a grade. The grade is the action code, and the two are independent.
PSC action codes in full
The action code is where the consequence lives. These are the ones that appear on reports, with what each actually obliges and who has to do it.
Code
Meaning
Who has to act
The clock
Detainable?
10
Deficiency rectified
Already done, during the inspection
None — closed on the spot
No
15
To be rectified at the next port
The ship, before or on arrival
Next port of call
No
16
To be rectified within 14 days
The ship, wherever it is
14 calendar days
No
17
To be rectified before departure
The ship, in this port
Before sailing — no re-verification
No
19
Safety management audit required before departure
The company, with an auditor
Before sailing
Effectively holds the ship
21
ISM corrective action by the company within 3 months
The office, not the ship
3 months
No
30
Detainable deficiency
The ship, verified by the officer
Until fixed and re-inspected
Yes
46
To be rectified at agreed repair port
The ship, at a named facility
On arrival at that facility
A negotiated outcome
99
Master instructed to…
Whoever the written instruction names
As written
Read it — it is non-standard
Code 30 is how the Tokyo MoU marks a detainable deficiency; the Paris MoU records the same thing with a grounds-for-detention flag rather than a code in that position. The practical effect is identical, but if you work across both regimes expect the report to look different.
Detainable or not: the test is about the voyage
Here is the point that changes how a finding should be read. Detainability is not a fixed property of a deficiency. The same inoperative item can be detainable on one ship and not on another, in one port and not the next, because the question the officer is answering is about the voyage in front of the vessel.
Three consequences follow from that, and they are worth stating because crews argue the wrong points at closing meetings.
01
Arguing severity rarely helps
Saying a defect is minor addresses a question nobody asked. The relevant argument is about the voyage: what is actually planned, over what distance, in what conditions, with what redundancy still available.
02
Redundancy is the strongest card
Demonstrating that a second means exists, works, and is understood by the crew speaks directly to unreasonable danger. It is evidence rather than opinion.
03
Code 46 exists for exactly this
Permission to sail to an agreed repair port is the regime acknowledging that a short, controlled voyage is a different proposition from the intended one. It is worth asking about before accepting a detention.
Code 17 against code 30: the re-verification line
These two cause more confusion than the rest combined, because both stop the ship sailing in its current state. The difference is who has to be satisfied.
17
Rectify before departure
The ship does not sail until it is put right, but there is no detention and no re-verification. The master confirms the rectification and the vessel proceeds. It costs port time, and it does not appear in the ship’s history as a detention.
30
Detainable deficiency
The ship is held. The officer returns, inspects the rectification and releases it. The detention is recorded against the ship and the company, is notified to the flag State, and remains visible for years.
In practice the distance between the two is often a single demonstration at the closing meeting. A finding heading for code 30 that can be rectified immediately, in front of the officer, with the function proven, may be recorded as rectified instead. The window for that closes when the officer leaves the ship.
How non-detainable findings turn into detainable ones
The most expensive misreading of the code system is assuming that a page of non-detainable findings is a good outcome because none of them individually holds the ship. It is not how an experienced officer reads the same page.
Volume becomes a system finding
Several individually minor deficiencies spread across different areas can together demonstrate that the safety management system is not functioning — converting findings that would each have carried a deadline into a single detainable ISM deficiency.
Repetition is evidence
The same finding appearing again after it was coded and closed says the close-out did not work. That is a management failure rather than a technical one, and it is read accordingly.
Carried items invite scrutiny
An open code 15 or 16 at the next port is both a thing to check and a reason to look harder at everything around it. Arriving with it closed and evidenced removes the invitation.
Expired deadlines are their own finding
A three-month company action discovered open at four months is worse than the original deficiency, because it demonstrates that the company does not track its own commitments.
Which categories most often produce detentions, and how that accumulation effect works in practice, is set out in our guide to the top detainable deficiencies.
Documenting rectification so a finding closes
Every code except 10 leaves something open, and what closes it is evidence rather than action. The standard differs by code, and matching the evidence to the code is what stops an item being questioned later.
Codes 15 and 16A dated record of the work with before and after photographs, the part fitted or the test result, and the item marked closed against the original wording. Keep it aboard — the next authority may ask.
Code 17The same evidence, produced before departure, retained even though nobody verified it. If the item recurs, this file is what shows the rectification was real.
Codes 19 and 21An audit or corrective action record from the company, addressing the system rather than the symptom, with the root cause stated and the procedure change attached. A repair record does not close a management finding.
Code 30Whatever the authority specifies for release, agreed in writing before work starts, plus any class or flag attendance required. Assumed scope is the usual reason a release visit fails.
Code 46Evidence that the ship reached the agreed facility and that the work was completed there, closed with the authority that granted it rather than with the repair yard.
Code 99Read the written instruction, do exactly what it says, and record against its wording. It fits no template, so nothing about closing it should be assumed.
The three codes most often mishandled
21
Belongs to the office, falls off the ship
A three-month company action is raised during a port call, recorded on the ship’s report, and then owned by nobody because the ship cannot close it and the office never received it as a task. It is the single most commonly expired code.
15
Travels faster than the ship
Crews treat it as a deadline at the next port. The next authority treats it as a known open item and a starting point. Those are very different things, and the second is the one that matters.
99
Non-standard, therefore unremembered
Because it carries a written instruction rather than a standard meaning, it does not fit any tracking habit and is the code most likely to be filed and forgotten. Transcribe the instruction into the tracking system in full.
The preparation that keeps findings off the report in the first place, and what inspectors examine across the core areas, is covered in our guide to PSC inspection preparation and deficiencies. What the resulting record does to inspection frequency afterwards is covered in our guide to the Tokyo MoU targeting regime.
How Marine Inspection keeps a code from escalating
Codes escalate for administrative reasons far more often than technical ones: a deadline nobody owned, an evidence file that was never assembled, a company action that stayed on the ship’s report. That is a records problem with a records answer.
What the system holds
Each finding stored with both numbers — the deficiency code and the action code — so the deadline and the enforcement level are properties of the item rather than knowledge held by whoever attended the inspection.
Deadlines that chase themselves14-day and three-month clocks tracked to their dates and escalated before expiry, including codes that belong to the office rather than the vessel.
Evidence matched to the codePhotographs, work records and test results attached to the finding they close, in the form that code requires.
Open items visible before arrivalCarried-forward codes shown against the vessel ahead of the next port call, where the next inspection will begin.
Repeats surfaced across the fleetThe same code recurring on several ships flagged as a pattern, before an auditor reads it as a system failure.
A code with an owner and a date rarely becomes a detention
Marine Inspection records every PSC finding with its deficiency and action code, tracks the deadline each code carries, holds the closing evidence against the item, and shows what is still open before the ship arrives anywhere.
What is the difference between a deficiency code and an action code?
The deficiency code is a five-digit number identifying what was found, with the first two digits naming the area — 01 certificates and documents, 07 fire safety, 11 life-saving appliances and so on. The action code sitting beside it carries the deadline and the enforcement level. The deficiency code says nothing about severity.
Which action codes are detainable?
Code 30 marks a detainable deficiency under the Tokyo MoU, with the Paris MoU recording the same thing as a grounds-for-detention flag. Code 19, requiring a safety management audit before departure, holds the ship in practice. Codes 10, 15, 16, 17 and 21 are not detainable, and code 46 is a negotiated permission to sail to an agreed repair port.
What does code 17 mean exactly?
To be rectified before departure. The ship does not sail until the item is put right, but there is no detention and no re-verification — the master confirms it and the vessel proceeds. It costs port time without producing a detention on the record.
What makes a deficiency detainable?
Whether the ship can proceed to sea without unreasonable danger to safety, health or the environment on the intended voyage. Detainability is therefore not a fixed property of the defect: the same finding can be detainable before an ocean passage and not before a short coastal move to a repair berth.
Can several minor deficiencies cause a detention?
Yes. Multiple individually non-detainable findings spread across different areas can collectively demonstrate that the safety management system is failing, which converts them into a single detainable ISM deficiency. Volume and spread matter, not only individual severity.
Which code is most often missed?
Code 21 — ISM corrective action by the company within three months. It is raised during a port call and recorded on the ship’s report, but the ship cannot close it and the office often never receives it as a task, so it expires quietly and is found at the next inspection.
How should a rectification be documented?
Against the original wording of the finding, with a dated record, before and after photographs, the part fitted or the test result, and the item marked closed. Management codes such as 19 and 21 need an audit or corrective action record addressing the cause, not a repair record.
Does a rectified deficiency still count against the ship?
Yes. Even code 10, rectified during the inspection, appears on the record and counts toward deficiency history, which is a scored factor in the risk profile that decides how often the ship is inspected.
What is code 99?
Master instructed to — a written, non-standard instruction. Because it carries no standard meaning it fits no tracking habit and is the code most often filed and forgotten. Transcribe the instruction in full into whatever system tracks the other codes.
Decode it once
Read the second number
Marine Inspection holds both codes against every finding, with the deadline each one carries, the evidence that closes it and the fleet-wide view of what keeps coming back — so a code is managed from the day it is written rather than remembered at the next port.
