A Planned Maintenance System (PMS) is the structured way a ship operator plans, executes and records maintenance on every piece of equipment on board. It turns manufacturer recommendations, class requirements and company experience into a schedule of jobs — and keeps the evidence that those jobs were done.
The ISM Code requires companies to establish procedures to ensure that the ship is maintained in conformity with relevant rules and regulations, with inspections at appropriate intervals, non-conformities reported and corrective action taken, and records kept. A PMS is how most fleets meet that expectation day to day.
The building blocks of a ship PMS
1. The equipment hierarchy
Everything starts with a model of the vessel: systems (propulsion, electrical, utilities), equipment (main engine, generators, pumps, purifiers) and maintainable components. Good hierarchies also hold maker, model, serial number and certificates, because those details are what you search for when a fault appears on more than one ship.
2. Standard jobs and schedules
A standard job describes a piece of maintenance once — instructions, resources, materials, questionnaires, attachments — and attaches a schedule to it. Schedules are typically calendar-based (every 3 months), running-hour based (every 2,000 hours) or both, whichever comes first.
3. Work orders
When a job falls due, the PMS creates a work order. Crews execute it, record readings and findings, attach photos and close it. The status lifecycle — Created, Due, In Progress, Postponed, Completed, Closed or Cancelled — is the backbone of your compliance numbers.
4. Postponements and approvals
Real operations mean some jobs cannot be done on time. A mature PMS lets the vessel request a postponement with a reason, and lets shore approve, adjust or reject it — with the decision recorded against the work order rather than buried in an email thread.
5. History and spares
Maintenance history, defects, critical spares and certificates complete the picture. This is the record auditors, vetting inspectors and your own superintendents rely on.
Calendar vs running-hour maintenance
Calendar jobs are simple: every N days. Running-hour jobs depend on how much the machinery has actually run, which makes them more accurate for engines and generators — but only if the hours are recorded reliably. That is why linking daily machinery reports, or AMS data, to the PMS matters: transcription errors in running hours quietly break maintenance schedules.
What to look for in PMS software in 2026
- Offline-first operation on board — a local database, not a web page that needs the internet.
- Acknowledgement-based synchronisation so records are never lost when the link drops.
- A shore back-office with fleet-wide search and bulk editing of job libraries.
- Built-in postponement workflow and complete audit trail.
- Data-quality checks for duplicate jobs and missing equipment links.
- Dashboards that drill down to the source record.
- A path to AI: searching manuals and maintenance history in plain language.
How NauticalFlows approaches PMS
NauticalFlows runs a desktop PMS application on every vessel against a local database, with incremental synchronisation to a central shore platform. Superintendents manage job libraries, approvals and readings on the web; MARKS adds AI retrieval over manuals and history. The result is one maintenance truth shared by vessel and shore.