ISM Code: Who It Applies To and the 5 Mistakes That Lead to Detention
- BoatOn
- 6 days ago
- 6 min read
688 ships detained in 2025 in the Paris MoU region alone, out of 16,474 inspections. In most cases the inspector did not find a single dramatic failure. He found an accumulation of small gaps that pointed to a safety management system nobody was really running.
The ISM Code is exactly what gets judged in those moments. Here is what it actually requires, who it applies to, which documents it imposes — and the five mistakes that come up again and again.
What the ISM Code actually is
The ISM Code (International Safety Management Code) is the international standard for the safe management and operation of ships and for pollution prevention. It does not prescribe a piece of equipment to install. It prescribes an organisation to put in place, to document and to prove.
It sits in Chapter IX of the SOLAS Convention. That placement changes everything: the Code is not a voluntary good practice, it is a treaty obligation, and non-compliance is a valid ground for detention.
Its origins are historical. After several serious accidents in the late 1980s — including the loss of the Herald of Free Enterprise — the inquiries showed that human error on board was only the visible part of the problem: shore-side management failures mattered just as much. Lord Justice Sheen summed those failures up in a phrase that stuck, “the disease of sloppiness”.
The goal stated by the IMO is therefore cultural as much as regulatory: moving away from unthinking compliance with external rules towards thinking self-regulation of safety.
Who does the ISM Code really apply to?
The trigger is not the length of the vessel. It is gross tonnage combined with the type of operation.
Since 1 July 1998: passenger ships, oil tankers, chemical tankers, gas carriers, bulk carriers and high-speed cargo craft of 500 GT and above engaged on international voyages.
Since 1 July 2002: other cargo ships and mobile offshore drilling units of 500 GT and above on international voyages.
Commercial yachts follow the same logic. Above 500 GT on international voyages, the ISM Code applies in full: documented SMS, DOC for the company, SMC for the ship. Below that threshold, most flags require a scaled-down system — the mini-ISM — for which Chapter 23A of Part A of the Red Ensign Yacht Code provides a framework. That system is not auditable in the strict sense, but its actual use is checked during annual surveys.
Beware of the reverse reasoning, which is common: not being subject to the ISM Code does not remove the need for a safety management system. France's Division 237 on offshore maintenance vessels, in force since 15 January 2026, and the third edition of the Workboat Code are two recent illustrations.
The three documents that make — or break — your compliance
The ISM Code takes shape through three clearly distinct objects. Confusing them causes half of the problems seen during verifications.
The SMS (Safety Management System) is the system itself: safety policy, procedures, responsibilities, maintenance plan, non-conformity management, emergency preparedness. This is the substance.
The DOC (Document of Compliance) certifies the company for specific ship types. It is valid for five years, with annual verification.
The SMC (Safety Management Certificate) certifies one given ship. It is valid for five years, with one intermediate verification between the second and third anniversary.
The rule that catches out the most fleets: a ship cannot hold a valid SMC without a valid DOC covering its type. Adding a ship type to your fleet without extending the DOC creates an immediate non-conformity, even when the vessel itself is faultless.
The Designated Person Ashore, the underrated link
The Designated Person Ashore (DPA) is the shore-based person who provides the link between the ship and the highest level of management in the company. That direct access to management is a requirement of the Code, not an org-chart convenience.
The role: verifying and monitoring the safety and pollution prevention activities of each ship, organising and monitoring internal audits, and making sure auditors are both independent and trained.
Internal audits must be carried out at intervals not exceeding twelve months, on board as well as ashore. A three-month extension is allowed in exceptional circumstances — that is a safety valve, not a working rhythm.
The classic mistake is a DPA appointed on paper, with no dedicated time and no real access to management. An inspector spots it quickly, simply by asking a crew member who they turn to when they find a non-conformity.
The 5 mistakes that lead to detention
1. A generic SMS
A manual bought or copied, never adapted to the ship. The test is immediate: the inspector asks a crew member to describe a procedure, and the answer does not match the document. An SMS describing a vessel nobody recognises is an SMS that does not exist.
2. Reconstructed records
Maintenance logs, drills, hours of work and rest filled in the day before the inspection. Traceability is precisely what is being proved: batched, backdated entries are a strong signal, and the inspector will dig deeper elsewhere.
3. A maintenance plan that is not alive
The ISM Code requires the company to establish procedures ensuring the ship is maintained in conformity. The Paris MoU 2025 report is revealing about the details that give away an unmanaged system: fire doors 3.2% of recorded deficiencies, engine room cleanliness 1.3%, general electrical installations 1.3%. Nothing spectacular — but a pattern. Our preventive maintenance guide sets out the method.
4. Non-conformities never closed out
An internal audit finding left with no corrective action, no owner and no closing date. That is more damaging than an audit never performed: the company identified the gap and did not deal with it. The Code requires the full loop, from finding to effectiveness check.
5. A certification scope out of step
New ship type, new flag, new activity: the DOC is not extended and the gap surfaces at the first inspection. It is a purely administrative error, but it immobilises a ship just as reliably as a breakdown.
What the 2025 figures tell us
The Paris MoU annual report for 2025 records 16,474 inspections, 51,797 deficiencies, 4,744 detainable deficiencies, 688 detentions and 19 bans. The detention rate rises to 4.18%, against 4.03% in 2024.
Deficiencies directly linked to the ISM Code account for roughly 4.5% of the total. The figure looks modest, but the Paris MoU makes one point clearly: detention rarely follows from an isolated deficiency. It is the accumulation of gaps, often individually non-detainable, that flags a failure to implement the SMS.
The most represented categories confirm that reading: fire safety (SOLAS Chapter II-2) 17.2%, structural and electrical elements (SOLAS Chapter II-1) 11.3%, health protection and living conditions on board (MLC Title IV) 10.4%. We looked at those trends in detail in our analysis of rising PSC detentions.
Keeping your SMS alive without losing your evenings
The ISM Code does not ask for more paperwork. It asks for paperwork that is dated, signed, findable and consistent with what actually happens on board.
In practice that means keeping in one place the maintenance plan and its records, non-conformities and their corrective actions, drills, and ship and crew certificates. As soon as those elements live in separate binders and spreadsheets, consistency slips — and consistency is exactly what the inspector is looking for.
An SMS is not judged on its thickness, but on its ability to produce the evidence of what was done in thirty seconds.
Two recent developments reinforce that expectation. Since January 2026, SOLAS amendments explicitly bring cyber risk management into safety management systems. And the MASS Code, in force since 1 July 2026, opens the way to safety management systems that will have to describe operations without permanent human presence on board.
BoatOn Book centralises the maintenance plan, time-stamped records, document management and crew certificates in a single tool that works on board even offline. For setting up or fully revising an SMS, BoatOn Consulting supports shipowners on the ISM and ISPS codes.
Book a BoatOn Book demo — thirty minutes to see how your SMS can become an everyday tool rather than a binder you dust off before the inspection.
Sources: IMO (ISM Code), Paris MoU — 2025 Annual Report, IIMS, SAFETY4SEA, French Ministry for the Sea (ship safety regulation).
