The engine runs on hours, the life raft on a date, and the flares have their deadline printed on them.

Anyone searching for "how often should boat maintenance be done" expects a legal table, like the one for car servicing. There isn't one. Italy's Recreational Boating Code (D.Lgs. 171/2005) and its implementing regulation — the D.M. 29 luglio 2008, n. 146 — set out which safety equipment you must carry on board, depending on how far you go from the coast. They almost never set how often that equipment must be serviced.

The intervals come from three other sources, and recognising them is half the job. The manufacturer's manual dictates the engine service, the life raft overhaul, the EPIRB battery, the maintenance of self-inflating lifejackets. The date printed on the device applies to pyrotechnic distress signals and to medicines: it's right there, and it isn't negotiable. The technical standard applies to portable fire extinguishers, which follow UNI 9994-1 on board just as they do ashore.

Then there's a fourth family that has little to do with maintenance but expires all the same: the documents — safety certificate, insurance policy, boating licence, radio station licence. This is the part that gets forgotten most often, because it doesn't live on the boat but in a drawer.

A marine engine's service doesn't have a date: it has two thresholds. Manuals call for a job "every so many engine hours or every so many months, whichever comes first", and in recreational use — few outings and many months laid up — it's almost always the calendar threshold that trips first. An outboard doing thirty hours a year reaches its service on the months; the engine of a rental RIB reaches it on the hours, halfway through the season.

What the job covers is stated in the manual and changes from engine to engine: oil and filter, fuel filter and water separator, leg oil or gearbox oil, raw-water pump impeller, belts, spark plugs, anodes. Some of these items have an interval of their own, shorter or longer than the service — the impeller and the anodes are the typical cases — and need to be tracked separately, not "whenever the service happens".

The one piece of data that makes all of this manageable is the hour counter. Writing down the reading at the end of an outing takes ten seconds and turns a feeling ("it'll be about a hundred since last time") into a number you can subtract from. Without that reading, the hours-based deadline doesn't exist: only the memory of the last service does.

The life raft is overhauled at the interval the manufacturer sets, at a servicing station it has authorised: typically that means two or three years depending on the model, but the number that counts is the one written on your life raft's certificate, not a general rule. At the overhaul it's opened, inflated and checked along with the equipment it contains — that too has deadlines of its own — and comes back on board with a certificate and a new date.

The practical problem is that the date is printed on the canister, and the canister sits on deck or in a locker, often lashed down: nobody reads it until it's needed. If the life raft sits in a cradle with a hydrostatic release unit, the release unit carries its own printed date too, independent of the life raft's. That's two deadlines, not one.

The EPIRB has a battery with a deadline set by the manufacturer and replaced by a service centre — it isn't a battery you swap on board — and it has to be registered, so that the code it transmits tells whoever comes looking for you which vessel it is and who to call ashore: if the boat or its owner changes, the details need updating. Self-inflating lifejackets have two parts with a deadline — the gas cylinder and the firing mechanism — with the check intervals shown on the model's manual.

The list of what you must carry on board sits in Annex V of the D.M. 146/2008 and is organised by distance band from the coast: within 300 metres, within 1, 3, 6, 12 and 50 miles, and with no limit at all. The further out you go, the longer the list gets: to the lifejackets — one for every person on board — are added, band by band, buoy lights, distress signals, compass, VHF radio, life raft and EPIRB beacon. The life raft appears from the bands beyond 12 miles.

For a pleasure craft, what navigation it's cleared for shows up in the boat's papers; for a small craft, in practice you go only as far as the equipment you carry on board allows. It's worth reading the Annex once, with the actual distance band you sail in mind.

Fire extinguishers follow a logic that has nothing to do with distance: their number and type depend on the engine's power and on whether there are cooking appliances, and they must be units of a type approved for use on board — not just any extinguisher bought at a hardware shop. Maintenance, on the other hand, is the same as for any portable fire extinguisher: inspection at least every six months by a qualified maintenance technician, then overhaul and pressure test on their own intervals, which depend on the extinguishing agent and which our fire extinguisher deadlines guide explains one by one.

One last thing to watch: how the word "deadline" should be read in this list. Some equipment genuinely expires, with a date on it: pyrotechnic signals, medicines, batteries. The rest doesn't expire but has to be in working order, and that's a condition you check by looking — the buoy light that switches on, the lifebuoy with no cracks, the bilge pump that actually pumps, lifejackets in the right size for whoever you have on board.

Document dates run in parallel with those of the equipment, and they're no more forgiving. Third-party liability insurance is compulsory for powered craft and doesn't renew itself. The boating licence — required beyond six miles from the coast, for personal watercraft, and above the power threshold set by the Code — is valid for ten years, five past the age of sixty, and renews with a medical check-up.

A pleasure craft's safety certificate renews with a periodic survey, on the date written on the certificate itself. Add to that the operating licence for the onboard radio station, covering the VHF and the EPIRB, which has to be kept on board and updated whenever the equipment or the owner changes.

Then there are the documents that maintenance itself produces, which nobody looks for until they're all needed at once: the certificate from the life raft's last overhaul, the tag and job report for the fire extinguishers, the service invoice with the hours written on it, the boatyard's report, the equipment manuals. Keeping them attached to the item they refer to is more useful than keeping them in chronological order: when you need the life raft's certificate, you need that one, not the 2024 folder.

The same goes for the day the boat changes hands: a boat with a documented history is easier to negotiate than one with a box of invoices, for the same reason a car with a stamped service book is worth more. It isn't the paper itself, it's the proof that maintenance was done when it needed doing.