Ship maintenance software: build or buy for small fleets

The file is called "Fleet_maintenance_V7_FINAL_ok.xlsx". It lives on the fleet manager's laptop, copies travel to the vessels by e-mail, and nobody is quite sure any more which version is the truth. Then one day, in a management meeting, someone suggests "getting a small tool built" by a web agency or a partner's nephew who codes. That is precisely the moment the real question surfaces: to run maintenance across a fleet of 2 to 30 vessels, do you need a spreadsheet, an in-house tool or dedicated ship maintenance software?

We have this conversation every week with fishing companies, passenger operators, pilot stations and offshore support owners. The honest answer is not a feature-by-feature shoot-out between a product and a spreadsheet. It is a comparison of three trajectories over three to five years: what each one really costs, what risks it loads onto operations and compliance, and what it leaves behind the day the author of the file — or of the code — leaves the company.

This article puts figures on each of the three options, walks through the costs the in-house scenario systematically forgets, and then gives you the three-number decision method we run with the fleets that consult us.

Three ways to run fleet maintenance

Before going into detail, here is the landscape. The three options do not play in the same league on cost or on risk, and that is exactly what makes the comparison useful.

The first two columns look economical, and in both cases it is an optical illusion for the same reason: the cost has simply been moved to where nobody measures it.

The spreadsheet: free until the day it isn't

Excel costs nothing, everyone knows how to use it, and for a single vessel with a single user it does a job. The trouble starts at two vessels and becomes structural at five. The hours pile up without ever appearing in a budget: engine hours re-keyed, due dates recalculated by hand, monthly consolidation of each vessel's file, hunting down contradictory versions. Across the fleets we audit, this invisible work commonly runs to 2 to 4 hours per week per vessel.

What a spreadsheet will never do

• Work offline in the engine room: the chief engineer writes in a notebook, re-keys it in the office — or doesn't.
• Raise alerts: a spreadsheet calls nobody when a safety survey or an oil change falls due; someone has to remember to open it.
• Prove anything: an edited cell leaves no date, no author, no previous value. In an audit, an Excel file is arguable; a time-stamped history is not.
• Connect anything: no link between the work order, the part drawn from stores and the replenishment order.
• Survive: one corrupted file, one overwrite, one stolen laptop, and the fleet's maintenance history is gone.

The hard limit is regulatory as much as operational. Chapter 10 of the ISM Code requires maintenance to be planned, carried out and recorded; a Port State Control inspector asking for evidence that a critical system was tested expects better than a spreadsheet row that can be edited after the fact. We have costed this "free" option line by line in Excel versus a maritime CMMS, where it turns out to be the most expensive per hour actually spent.

Building your own ship maintenance software: a second business you never wanted

The in-house scenario is seductive because it promises a tool "that fits our processes exactly". And it is true: on delivery day, a bespoke tool fits your organisation perfectly. The problem is that delivery day is the only day it will. From the next morning, your organisation moves — a vessel of a new type joins the fleet, a requirement from your classification society evolves, a charterer imposes its own reporting — and every gap between the tool and reality becomes a small IT project, with its lead time, its quote and its single point of contact.

The bus factor

Almost every in-house tool we come across rests on one person: a freelance developer, a small agency, sometimes an enthusiastic employee. Let that person change jobs, raise their rates or retire, and the owner is left with software nobody dares touch, no documentation, and a technology stack that has aged. We have seen fleets go back to paper because the in-house tool stopped opening after a server update. A broken spreadsheet can be rebuilt; orphaned software cannot.

Software is never finished

This is the blind spot in the initial quote. Software in production demands a continuous stream of work that a product vendor spreads across hundreds of customers and that you would carry alone:

• Corrective and evolutive maintenance: allow 15 to 20 % of the initial build cost, every year, simply to keep the tool running and tracking your needs.
• Technical updates: new iOS and Android versions, security patches on libraries, server and database migrations.
• Backups and hosting: your maintenance history becomes critical data that must be backed up, restorable and protected.
• Cyber security: the requirements flowing from IACS UR E26/E27 and IMO resolution MSC.428(98) are pulling the whole ecosystem towards standards a homemade tool will not keep up with.
• Regulatory watch: when an STCW deadline, an MLC 2006 requirement or an IMO FAL form changes, someone has to change the code. For a software vendor, that watch is the business; for a shipowner, it is a distraction.

And then there is the workstream every internal project underestimates: offline operation. An app that must record work orders in an engine room with no signal, queue the operations and synchronise at the port call without overwriting other users' entries represents years of hardening in real conditions. It is precisely the part you cannot see in a demo — and the part that matters at sea.

How much does it really cost to build ship maintenance software in house?

Budget €60,000 to €250,000 for a first version covering planned maintenance, equipment records and history, with a mobile app that works offline — then 15 to 20 % of that amount every year for maintenance, hosting and evolutions. Over three years, an in-house tool for a mid-sized fleet almost always passes €150,000, while a dedicated maritime CMMS subscription stays in the range of a few thousand euros per vessel per year.

Here is the order of magnitude over three years for a six-vessel fleet. The amounts are illustrative and deliberately conservative for the in-house scenario; redo the sums with your own quotes.

The gap is an order of magnitude, before putting any value on project risk: in the in-house scenario you pay most of the money before knowing whether the crews will adopt the tool, whereas a subscription stops if the product does not deliver. The full method for comparing costs of ownership is in our article on the three-year TCO of a maritime CMMS.

What you actually buy with dedicated ship maintenance software

A feature-by-feature comparison misses the point. When you choose a maritime CMMS — call it a planned maintenance system if your flag or class does — you are not buying software: you are buying the accumulated experience of hundreds of vessels that have already hit your problems.

• Workflows that are already compliant: the traceability the ISM Code demands, the reports auditors expect and the survey calendars are in the product, because hundreds of audits have already run over them.
• A mobile app hardened at sea: the offline synchronisation has been proven on trawlers, ferries and support vessels — not on a simulator.
• Modules that talk to each other: the work order draws down the spare parts inventory, the reorder threshold triggers the purchase request, the certificate falls due in the same calendar as the survey — with no custom development.
• Regulatory updates delivered with the product: when a requirement changes, the vendor handles it once for the entire installed base.
• A roadmap that moves without you: every improvement funded by other customers benefits you, whereas every evolution of an in-house tool comes out of your cash flow.
• A tool your next officers may already know: a chief engineer joining the fleet gets productive in a few hours on a market product, against several weeks on a tool that exists nowhere else.

One note of caution: dedicated does not mean any CMMS. A generic industrial CMMS bent into shape for ships reproduces part of the in-house tool's defects — we have detailed the differences in maritime CMMS versus generic CMMS. The maintenance module must think in running hours and port calls, not just calendar dates.

The three cases where building is defensible

An honest comparison has to say it: there are situations where building makes sense.

1. The very large fleet: beyond several dozen vessels, with an IT department, a permanent product budget and a team that will outlive individual departures, the equation can flip. That is not the situation of a fleet of 2 to 30 vessels.
2. The genuinely unfindable process: if your operation rests on a workflow no market product covers, verify it objectively first — our 32-criteria selection scorecard exists for exactly that. Nine times out of ten, the "unique" requirement turns out to be a configuration setting.
3. Building at the edges, not the core: the healthiest compromise is to buy the core — maintenance, inventory, certificates — and build around it, through exports and interfaces, whatever is truly yours: a specific operations report, a link to your accounting system. You keep control of what makes you different without carrying the weight of the foundation.

The three-number decision method

You do not need a consultancy study. Three numbers, which you can gather in a week, are enough to settle it.

• The monthly hours spent feeding the current system: entries, re-entries, consolidations, chasing. Multiply by the loaded hourly cost of your technical management. That is your real running cost, the one that appears in no budget.
• The full cost of your last preventable breakdown: the one whose due date was known but buried in a file — emergency parts, express freight, a rescheduled port call, penalties. That is your cost of risk.
• The days needed to make a new chief engineer autonomous on your current tools. That is your cost of handover, and you pay it at every crew change.

If the total worries you, do not jump straight to a demo: run a structured selection. Start by formalising the requirement with our guide to writing a maritime CMMS requirements specification, score the candidates on the criteria grid, then prepare the rollout with the phase-by-phase implementation checklist — while avoiding the six mistakes that sink CMMS rollouts, starting with trying to digitalise everything at once across the whole fleet. One pilot vessel, one maintenance module, one measurable result within three months: that is the trajectory that succeeds.

And if you are still hesitating between the three options, ask the legacy question: in five years, what will your choice leave behind? A spreadsheet leaves scattered files. An in-house tool leaves code nobody maintains. A CMMS leaves a structured, exportable maintenance history that follows the fleet — and even adds value to a vessel at resale. Our complete maritime CMMS guide sets this choice in the wider digitalisation picture.

Key takeaways

For a fleet of 2 to 30 vessels, the spreadsheet is expensive in hours and proves nothing in an audit; the in-house tool is expensive in euros and rests the fleet's entire maintenance history on one person; dedicated ship maintenance software spreads across hundreds of vessels a development and regulatory-watch cost that no owner of this size can carry alone. Building only makes sense above a size where you can fund a permanent product team — and even then, the question deserves to be asked twice.

The decision comes down to three numbers: the hours spent feeding the current system, the cost of the last preventable breakdown, the time needed to train a new officer. If the total bothers you, a structured selection — requirements specification, criteria grid, pilot vessel — takes a few weeks and commits infinitely less than an eighteen-month development project.

Smart Sailors is a maritime CMMS designed in Marseille by seafarers and deployed on more than 700 vessels, with a mobile app that works offline and 12 modules covering maintenance, inventory, purchasing and certificates without a line of code to write. Tell us about your fleet, or go straight to our pricing — from €10 per vessel per month, an order of magnitude below the cost of even the smallest build.