Spare parts inventory list for a 40–80 ft boat — what to carry and how to track it

Most breakdowns at sea are small parts: an impeller, a belt, a fuse, a hose clamp. The boats that get going again are the ones that had the part aboard and could find it. This is the list we see on well-prepared 40–80 ft yachts, motor and sail, and a method for keeping it true. Adjust quantities to your cruising range — a boat that is never more than a day from a chandlery carries less than one crossing an ocean.

Engine and generator spares

• Oil filters and fuel filters (primary and secondary) — two full changes per engine and per generator
• Raw-water impellers — two per pump, with gaskets and O-rings
• Drive belts — one full set per engine
• Engine oil — one full change plus top-up; gearbox and saildrive oil
• Coolant, one full fill; engine anodes, two sets
• Thermostat and gasket; injector pipes and washers if you carry the tools to fit them
• Hoses: one length of each raw-water and coolant hose size aboard, with double clamps
• Fuel lift pump or diaphragm kit; starter solenoid; alternator brushes or a spare alternator on long passages
• Outboard: spark plugs, impeller, gear-oil, pull cord, shear pins or prop nut

Electrical

• Fuses of every rating aboard, plus a spare of each breaker type you can swap
• Bulbs or LED units for navigation lights, anchor light and cabin lights
• Battery terminals, lugs, heat-shrink, cable in the main sizes, crimp tool
• Spare bilge pump and float switch — the single most-used spare on most boats
• Spare freshwater pump or pressure switch and diaphragm kit
• VHF handheld batteries; a spare masthead-light or a portable tricolour on sailing boats

Plumbing and heads

• Toilet service kit (joker valve, seals, pump) per head
• Freshwater pump pressure switch and diaphragm; accumulator
• Hose clamps in every size aboard, stainless; a selection of hose barbs and reducers
• Sea-cock handles, bungs (tapered softwood, one tied to each thru-hull), emergency epoxy
• Watermaker pre-filters (a season's worth) and pickling chemical
• Shower sump pump or float switch; macerator seals if fitted

Deck, rig and hull

• Sailing: spare halyard, sheets, blocks, shackles, a sail repair kit, spare batten, cotter and clevis pins
• Winch service kits: pawls, springs, grease
• Windlass: spare gypsy clutch cone or pawl, chain stopper pin, snubber
• Anodes for hull, shaft, prop and trim tabs; a spare prop nut and key on long trips
• Fibreglass repair kit, underwater epoxy, sealants (marine silicone and polyurethane)
• Fenders and lines: one spare of each; a spare anchor shackle and seizing wire

Safety and consumables

• Fire extinguisher (one spare, serviced), flares within date, spare EPIRB or PLB batteries where user-replaceable
• First-aid restock list checked monthly (see the first-aid category in your inventory)
• Duct tape, self-amalgamating tape, cable ties in three sizes, WD-40 or equivalent, rag, nitrile gloves
• Lubricants: winch grease, engine grease, silicone spray, penetrating oil

Tracking the inventory so it stays true

A list is only useful if it is right. The spares that let a boat down are the ones the list said were aboard and were not — used last season and never replaced. The method that works:

• One line per part, with a location on board that means something ("engine room, port locker, box 3"), a quantity, and the part number.
• A minimum quantity for each line. When stock drops below it, the part goes on the shopping list automatically — that is the whole point of the minimum.
• Deduct at the moment of use. If an impeller comes out of the locker, the count changes then, not at the end of the trip.
• Photograph the part and the box. A photo settles "is this the right filter?" in seconds.
• Count everything once a season and correct the list. The commissioning week is the natural time.

Do all of this in iVessel — and more

iVessel's spares inventory is built for exactly this list — and it keeps itself honest, because parts are deducted as they are used.

• Every spare has a location, a quantity, a minimum, a part number and a photo; scan a barcode to find it or add it.
• Log a service or fix an issue and the parts used come off the inventory automatically; when a line drops below its minimum it goes straight to the shopping list.
• Keep a land store ashore and transfer spares to and from boats, with the movement recorded.
• Every movement records who used what and when, so the list and the locker agree.
• Works offline at sea and syncs when you are back in range. iOS, Android and web.

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