How is it different from planned maintenance (PMS)?

A planned maintenance system raises the job when the calendar or the running-hours counter says so. Predictive maintenance raises it when the data says the machine needs it. In practice the two run together: class and flag expect a maintained PMS, and predictive work is layered on top of it for critical or expensive equipment where a fixed interval is either wasteful or not safe enough.

Does predictive maintenance replace the PMS?

No, and any vendor suggesting it does is misreading the regulation. The ISM Code requires a documented maintenance regime with inspections at appropriate intervals, and class-approved condition-based schemes still require an underlying planned system. Predictive maintenance changes when some jobs are done and adds evidence for deferring others; it does not remove the requirement to hold and evidence a plan.

What equipment is worth monitoring predictively?

Start where failure is expensive or dangerous rather than where data is easy: main engine and turbochargers, auxiliary generators, steering gear, critical pumps, purifiers, compressors and the shafting line. For low-criticality equipment a calendar interval remains the cheaper and entirely adequate answer.

Do you need expensive sensors to start?

Not to start. Most vessels already collect enough: engine-room log readings, noon reports, oil sample results and handheld vibration readings. The value comes from recording those consistently against the equipment record and trending them, which is a discipline problem before it is a hardware problem. Permanently installed sensors improve resolution on specific machines once the discipline exists.

How does predictive maintenance work with poor connectivity?

Readings must be capturable on the vessel with no link ashore, or they will not be captured at all. Full Ahead caches the vessel's data locally, accepts readings, photographs and sign-offs entirely offline, and queues them in a sync outbox that uploads automatically when connectivity returns — so the trend line has no gaps caused by the satellite bill.

Savings come from three places: avoided off-hire and emergency repair, reduced consumption of spares and lube oil that was being replaced early, and better dry-dock planning because the condition of major items is known in advance rather than discovered. The size of each depends on the fleet, so treat published percentages from vendors — including any you read elsewhere — with caution and measure your own baseline first.

Guide · Maintenance strategy

What is predictive maintenance for ships?

Q: What is predictive maintenance for ships?

Predictive maintenance is a strategy that uses measured condition data — vibration, temperature, oil analysis, performance deviation — to estimate when a piece of shipboard equipment will reach an unacceptable condition, and schedules the work shortly before that point. It sits between condition-based maintenance, which reacts once a threshold is crossed, and planned maintenance, which works to a fixed interval regardless of condition.

Predictive maintenance uses measured condition data to estimate when a machine will reach an unacceptable state, and schedules the work just before it does — instead of waiting for a calendar interval or a failure. This guide explains where it sits alongside planned maintenance, which parameters actually carry the signal, and what it takes to run at sea.

Condition monitoring readings and maintenance trends in Full Ahead

The four maintenance strategies, in order of maturity.

No fleet runs a single strategy. The question is which one each piece of equipment deserves, and criticality is what decides it.

Stage 1

Reactive (run to failure)

The machine is repaired after it breaks. Cheapest to plan, most expensive to live with — failures happen at sea, on the worst day, and often take a certificate or a charter with them.

Stage 2

Planned / preventive

Work falls due on a fixed calendar or running-hours interval, whether the machine needs it or not. This is what a classic PMS delivers and what class expects as a minimum.

Stage 3

Condition-based

Work is triggered by a measured parameter crossing a threshold — vibration, temperature, oil analysis, differential pressure. Effort follows evidence rather than the calendar.

Stage 4

Predictive

The trend in those parameters is projected forward to estimate when the machine will reach an unacceptable condition, so the work is scheduled into a convenient window before it does.

Which parameters actually predict failure.

A predictive programme is only as good as the parameters behind it. These six carry most of the signal on a conventional merchant vessel.

Vibration

Bearing wear, misalignment and imbalance in pumps, purifiers, turbochargers and shafting appear in the vibration signature long before they are audible.

Temperature & pressure deviation

Exhaust gas temperature spread across cylinders, scavenge air pressure, cooler differential and filter pressure drop each drift measurably before failure.

Lubricating oil analysis

Wear metals, water content and viscosity from routine samples give a direct read on internal condition that no external inspection provides.

Performance deviation

Rising specific fuel oil consumption or falling turbocharger efficiency against the vessel's own baseline is a whole-machine condition signal.

Running hours & load profile

Two identical generators with very different load histories do not wear at the same rate; hours alone are a poor proxy without the load behind them.

Insulation & electrical resistance

Megger readings trended over time show motor and cable degradation while there is still time to plan the replacement.

How to start without buying anything.

1. Rank equipment by criticality. List what stops the ship, endangers the crew, or breaches a certificate if it fails. That short list — usually twenty to forty items — is the only place predictive effort pays back.

2. Attach readings to the equipment record. The readings mostly exist already, scattered across engine-room log books and oil analysis emails. Recording them against the machine rather than the date is what turns them into a trend.

3. Set thresholds, then watch the slope. A threshold tells you the machine is in trouble now; the slope tells you when it will be. The second is the one that lets you book the work into a port call.

4. Keep the planned system underneath. Predictive findings should raise real jobs in the planned maintenance system with evidence attached, so class, flag and vetting see one coherent history.

5. Make it work offline. If a reading needs connectivity, it will be skipped on passage and your trend will have holes exactly where the load was highest.

Where Full Ahead fits.

Full Ahead holds the equipment register, the condition readings and the job history on one record, and works fully offline at sea. Performance-side signals come from ship performance monitoring, statutory work from the safety management registers, and the whole picture from the ship management platform.

Predictive maintenance questions.

Put condition data on the equipment record.

Thirty days free, no card, and the vessel arrives with an equipment register already in place.

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