How often should a boat be serviced?

Most outboard manufacturers specify a service every 100 hours or once a year, whichever comes first; Mercury and Yamaha state it that way for their outboards. Inboard intervals vary by model, for example 200 hours or once a year for Volvo Penta D1 engines.

How often should the impeller be replaced?

It depends on the engine. Mercury specifies replacing the water pump impeller of its 4/5/6 FourStroke outboards every 3 years or 300 hours. Volvo Penta specifies checking it on the D2-40 every 500 hours or once a year. Follow your manual.

Is there a printable boat maintenance checklist?

Yes. This page prints with tick boxes; use your browser's print dialog to save it as a PDF.

Boat Maintenance Checklist and Schedule (Printable)

A boat maintenance schedule has four rhythms: before every trip, during the season, every 100 hours or once a year, and longer intervals. The exact intervals for your engine are in its owner's manual; the examples below show how Mercury, Yamaha and Volvo Penta state them. Print this page or keep the list in Seaworthy, which reminds you before each item is due.

Before every trip

Engine oil and coolant level checked
Raw water strainer clean, seacock open
Cooling water flows from the tell-tale after starting
Bilge dry, bilge pump switches on
Fuel level and spare fuel for the planned trip plus reserve
Battery charged, main switch on
Navigation lights and horn working
Lifejackets on board for everyone, inflatable ones with intact indicator
Fire extinguisher, flares and first-aid kit on board and within date
Weather forecast checked

During the season (regularly)

Belts for wear and tension (Volvo Penta D1/D2: every 14 days)
Hoses and hose clamps for cracks and rust
Anodes for wear
Battery terminals clean and tight
Steering and throttle cables move freely
Rigging: shackles, split pins and terminals (sailboats)
Bilge pump float switch tested

Every 100 hours or once a year

Most engine manufacturers combine an hour count with a calendar limit. Volvo Penta's manual for its D1 and D2 sail engines puts the rule plainly: when both are given, the one occurring first applies.

Engine oil and oil filter changed
Gear lube changed (outboards and sterndrives)
Fuel filter and water separator replaced
Spark plugs checked or replaced (petrol engines)
Raw water pump impeller inspected
Anodes replaced if more than half wasted
Propeller removed, shaft greased, propeller checked for damage
Through-hulls and seacocks operated and checked
Gas installation checked for leaks

Example intervals from manufacturer manuals

These intervals apply to the named models. Other engines, even from the same manufacturer, can differ. Your owner's manual is the reference.

Engine	Oil and filter	Water pump impeller	New engine
Mercury 4/5/6 FourStroke outboard	Annually or every 100 hours	Replace every 3 years or 300 hours (dealer item)	See manual
Yamaha outboards	Annually or every 100 hours	Water pump included in the 100-hour kit for F115, F150, F200 and F300	Service after the first 20 hours
Volvo Penta D1-13/20/30 inboard	Every 200 hours or at least once a year	See manual	Change oil and filters after 20 to 50 hours
Volvo Penta D2-40 inboard	Every 500 hours or at least once a year	Check every 500 hours or at least once a year	Change oil and filters after 20 to 50 hours

Longer intervals

Impeller replaced, if your manual gives a fixed interval (Mercury 4/5/6 FourStroke: 3 years or 300 hours)
Hoses and exhaust elbow inspected for corrosion and replaced as needed
Standing rigging inspected by a rigger at the interval the rigger or mast maker recommends (sailboats)
Liferaft serviced (VIKING RescYou and Ocean Safety Ocean ISO: every 3 years)
Inflatable lifejackets serviced per the manufacturer (see the safety gear guide)
Antifouling renewed per the paint maker's instructions

Expiry dates for flares, extinguishers, lifejacket cartridges and beacons are collected in the safety gear guide.

Turning the checklist into reminders

In Seaworthy every item on this page becomes a maintenance task with its own interval: by date, by engine hours, whichever comes first, or at season start. You choose the lead days and the time of the reminder and tick the task off right from the notification; the logbook entry is written for you.

Boat maintenance checklist and schedule