Preventive maintenance plan: how to build and track it

Thursday, late afternoon. The vessel is two days away from dry dock and the superintendent asks for the list of overdue preventive maintenance. The chief engineer opens the plan spreadsheet, which has one tab per system and a few dates in red. Half the rows do not say when the task was last done, because whoever did it wrote it in the logbook and never copied it to the file. The other half do, but nobody knows whether the date is the day of the work or the day someone updated the cell.

This article shows how to build a preventive maintenance plan that works outside a spreadsheet, for a fleet of vessels or for the equipment at a support base or an industrial plant. You will find the difference between the types of maintenance, a checklist of what to register and a script for putting the plan to use. If the main problem today is that each unit uses a different checklist for the same inspection, start with the article on the digital inspection checklist, which covers standardizing the templates.

What is a preventive maintenance plan?

A preventive maintenance plan is the list of tasks each asset needs in order to keep working, with the interval, owner and evidence for each one defined before any failure. It answers four questions for every piece of equipment: what to do, how often, who does it and how to prove it was done.

At sea, this requirement is in the ISM Code, the International Safety Management Code of the IMO, the United Nations agency for shipping. Section 10 of resolution A.741(18) asks the company to have procedures to keep the ship in line with the applicable rules, to hold inspections at appropriate intervals, to report non-conformities with their possible cause, to take corrective action and to keep records of all of it. Item 10.4 asks for all of this to be part of the ship's operational maintenance routine rather than a separate control.

Ashore in Brazil, the reference for machinery and equipment is NR-12. The NRs are the regulatory standards on occupational safety and health issued by the Ministry of Labor and Employment. Item 12.11.1 says maintenance follows the method and interval set by the manufacturer or by a licensed or qualified professional. Item 12.11.2.2 calls for an execution schedule for preventive maintenance on items that affect safety.

Why does a spreadsheet plan leave tasks behind?

A spreadsheet plan leaves tasks behind because the spreadsheet holds the list but neither warns when something is overdue nor records who did the work. The next due date depends on someone remembering to update the cell after each job, and the record of the work usually lives somewhere else: the logbook, a paper form or a photo on a personal phone.

In the inspection and maintenance project we have maintained since 2022 for an operator of offshore support vessels, that was the starting point. Each vessel had its own checklists in spreadsheets, the same test was described differently from one vessel to the next and the onshore office only saw the result when the file arrived by email. Finding overdue items meant assembling everything by hand. The full case study describes how the system turned out.

There is also a visibility problem. NR-12, in item 12.11.2.1, requires the maintenance records to be available to the workers in operations and maintenance, to the internal accident prevention committee (CIPA), to the occupational health and safety service (SESMT) and to labor inspectors. A spreadsheet on the chief engineer's or the supervisor's computer rarely meets that in daily practice.

The third problem shows up with equipment that is almost never used. Item 10.3 of the ISM Code asks the company to identify the equipment and technical systems whose sudden failure may result in hazardous situations, and to regularly test stand-by arrangements and systems that are not in continuous use. An emergency fire pump or a backup generator can sit idle for months. If their test depends on someone remembering, it slips and nobody notices.

What changes between corrective, preventive and predictive maintenance?

The difference is what triggers the task: corrective maintenance starts after a failure, preventive follows a calendar or a usage count, and predictive starts from monitoring the equipment's condition. A well-built plan uses all three, and the system has to handle each one differently.

NR-12 covers the last two columns in the same item. For preventive maintenance on safety items, it asks for a schedule. For predictive maintenance, it asks for a description of the analysis techniques and the means of supervision. In the fleet system we maintain, equipment readings such as pressure and temperature are entered in the same flow as the inspection, and the system calculates the historical median of each reading to flag values outside the pattern. It is a simple way to start tracking condition without installing sensors.

What usually stays out of the first scope is spare parts inventory, purchasing and ERP integration. They are useful steps, but the plan needs to be registered and in use before the storeroom is connected to it.

What do you need to register for the plan to work?

For the plan to work, each asset needs a record with its criticality, and each task needs to be linked to that asset with its interval, steps, evidence and owner. The checklist below brings together what we have seen work in the inspection and maintenance systems we maintain.

To use the list, take one onboard system or one group of equipment at a time, for example firefighting or the generators, and answer each item with what exists today: a system, a spreadsheet, paper or nothing. The assets group comes first on purpose. Without a single equipment register, each task ends up describing the asset its own way, and the history of the same engine is scattered across rows that never meet.

Two items make a difference later. The first is the declined step with a reason. When the form does not let anyone record that something was not done, the technician marks it as done to be able to close it. In the vessel system, a step declined with a justification goes to the findings center, and what was postponed appears in the cumulative items center. The second is the interval with its source noted. When someone asks why a task is monthly and not quarterly, the answer needs to be in the record and not in the memory of whoever built the plan.

How do you put the plan to use?

The plan goes live best with one group of assets and one or two units, with the old spreadsheet kept as a reference for a short period.

1. Take an inventory of the assets. List vessels, equipment and systems with location and type, and check it with the people who operate them, because the paper inventory is usually out of date.
2. Flag the critical equipment. With maintenance engineering and the HSE team, mark which sudden failures create hazardous situations and which stand-by equipment needs periodic testing.
3. Build the tasks from the manuals. Each task becomes a template with sections, tests and steps, and each step states what to check and what evidence to record.
4. Set the interval of each task with the technical lead and note the source. The system creates the occurrences from it.
5. Start with one onboard system or one group of equipment in one or two units. Follow the first weeks and adjust the templates based on the questions from the people doing the work.
6. Put the findings center and the cumulative items list into the routine of the supervisor and onshore management, not only into the monthly report.
7. Connect the indicators to the company dashboard. In the vessel project, preventive maintenance compliance indicators go out through an API to the client's corporate dashboard.
8. Expand group by group and retire the spreadsheet, which becomes a historical file.

The plan has to work on a phone or tablet, because maintenance happens in the engine room, on deck or in the yard. We build this kind of system as apps for field teams, usually as a web system installed on the device. When preventive work turns into a report for a client, with photos and a signature, the article on the automatic service report shows what the field record needs to capture.

What if the vessel has no signal or the task depends on running hours?

When the vessel has no signal, the system has to define what works offline and how records sync when the connection returns. In the fleet system we maintain, the app is installed on the onboard device and stores the interface locally, and each project defines what has to run without signal. A finding opened on board shows up onshore as soon as the device has a connection. That rule has to be agreed in the system design, before development.

Tasks based on running hours call for another decision. Engines, generators and compressors usually have maintenance by hour meter rather than by calendar. The plan needs to know where that count comes from: a reading entered by the crew or another system that already records the hours. With the reading entered in the same flow as the inspection, the system can work out when the next task is due.

Then there is the plan that changes. The manufacturer revises an interval, the classification society asks for an extra test, the company decides to add an item after an incident. That is why the task template and the execution need to be separate things in the system. In the vessel project, fleet management edits the templates itself, a change applies to the next occurrences and the history of audits already run stays as it was.

When is a plan in a system not enough?

The system organizes the plan, creates the occurrences and keeps the records, but it does not decide what to do on each piece of equipment or how often. That stays with the manufacturer, maintenance engineering, the classification society and the HSE team. If the spreadsheet plan already had vague tasks or intervals with no source, moving it into a system does not fix them. The content review comes first.

Nor does it replace the permit to work or energy isolation before an intervention in a hazardous area. If the preventive task requires hot work, work at height or confined space entry, the next flow is the permit, and the article on the digital permit to work covers it. At a support base, asset maintenance usually sits alongside the gatehouse, permits and non-conformities. On the operations platform for a port support base that we have maintained since 2019, work orders and asset maintenance are a module on the same registry of people, companies and locations. The article on the port operations platform shows the order in which those modules usually come in.

If your maintenance plan still lives in a spreadsheet with dates in red, boosting.tech is a custom software company that builds this kind of system from the plans and checklists your team already uses. We have had systems online since 2018, and we can look at your case in a free diagnostic conversation. The details of how we work are in custom web systems.