Checklist for buying a boat

Reading time: about 12 minutes

A well-kept exterior says little about the condition of a used boat. The most expensive surprises lie in the hull, the engine and the papers. A close look would have shown them to you beforehand.

This checklist takes you step by step through a complete pre-purchase check. At the end you will find a separate block for buying a share, because there it is not only the boat that has to be right, but also the group and its rules.

This guide was written for owners and buyers in Germany. Legal, tax and boat-paper points refer to German law and practice; other countries may differ.

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Block A: Documents & papers

Clear these up before the viewing: no complete papers, no appointment.

• Boat papers / boat certificate present and made out to the seller? If the boat is entered in the ship register: look at a current extract from the register (owner, encumbrances).
• Hull number (HIN/CIN): does the entry in the papers match the number on the hull?
• CE declaration of conformity present? (Mandatory for boats first placed on the market in the EU since 16 June 1998; rule of thumb: built 1998 or later)
• Proof of VAT payment present? (if the import history is unclear, clarify with a tax adviser)
• Current insurance policy available to see?
• Maintenance history / service books complete, with no gaps?
• Stated engine hours plausible and backed up by the service books?
• Abroad: Which registration and which certificates does the flag the boat sails under require, and are they valid and present? (Clarify with the seller and the relevant harbour authority before buying.)
• Boat free of liens and mortgages? (The purchase contract must contain an assurance that the boat is free of third-party rights)
• Does the boat belong solely to the seller, with no spouse, no joint heirs, no bank as lienholder? (When buying the whole boat, all owners must sell. When buying a share, Block F applies.)
• Berth contract: remaining term, conditions, transferable to new owners?
• All keys present? (ignition, companionways and doors, lockers, fore and aft peaks)
• Operating manuals for boat, engine and accessories complete?

Rule of thumb: Missing documents are not a reason to push the price down, but a reason not to buy.

Block B: Hull & underwater hull

• Osmosis blisters on the underwater hull? (GRP hulls, the most common expensive single problem, especially on sailing boats over 10 years old)
• Condition of the antifouling: evenly applied, no bare patches or flaking?
• Hull: knocks, dents, signs of repair, gelcoat discolouration or filled areas as a sign of groundings?
• Sailing boats: keel bolts for rust, the seal between keel and hull: a wide gap or a silicone joint?
• Skin fittings: watertight, seacocks moving freely (not seized)?
• Shaft passage / stern tube watertight?
• Bilge: clean and dry? (Oil, water or fuel in the bilge is a warning sign)
• Deck gear: cleats, bollards, stanchions, fixings firm, no rust stains on the deck?
• Teak deck (if fitted): planks firm, no lifted areas? (Lifted teak planks are often a symptom of deck leaks underneath)
• Deck and teak: are there soft spots, moisture or loose bungs?
• Stringers and bulkheads inside (as far as accessible): no delamination, no damp penetrating?
• GRP: hairline cracks on the transom or star-shaped cracks in the gelcoat? (Hairline cracks on the transom can point to too powerful an engine, star cracks to impacts; a restless, pitted paint surface to damage that has been repainted)
• Steel hull: rust blisters outside, rust inside as far as visible, corrosion around skin fittings, shaft and rudder? (Only a surveyor can judge the welds, and the frames and stringers behind the lining)
• Aluminium hull: paint undamaged, no corrosion where it meets other metals?
• Wooden hull: grey or dark stains under the varnish, seams and planks firm, no musty smell? (With wooden boats always bring in a surveyor)
• Steering gear: check the rudder bearings and rudder tube for play and leaks. Play in the rudder is common wear that is easily overlooked.
• Smell test below decks: musty, diesel or mould? (An early indicator of leaks or standing damp)
• Upholstery and interior lining: water stains, discolouration, pressure marks?

Tip: Tap the deck and hull with your knuckle. Hollow-sounding areas in the GRP give away water damage you cannot see. The tap test does not replace a meter, though: for a reliable result, bring a moisture meter or commission an independent surveyor.

Block C: Engine & drive

• Cold start: arrive before the agreed time so that the seller cannot warm the engine up beforehand
• Oil level and oil colour: milky or cloudy = water in the oil = possible engine damage
• Cooling water: residue, discolouration, smell of exhaust?
• Exhaust system: soot marks, condition of clips and hoses?
• Engine hours: stated figure plausible? (Research the specific engine type; guide values vary widely by engine manufacturer and intensity of maintenance)
• Sterndrive: bellows in order? Cracks or perished rubber must be dealt with immediately. Ask for the date of the last bellows change, with the invoice (under the manufacturer’s schedule in some cases every 2 years, usual on the market every 4–6 years)
• Shaft drive: stern tube seal and shaft bearings, check the shaft for play. Ask for the date of the last seal change (manufacturers’ figures: depending on design about every 5–10 years)
• Pod drive: When was the last seal service, and when is the next one due? (Under the manufacturer’s schedule, depending on the series, after 1,200 to 3,000 engine hours, with no calendar limit; a trade article advises about five years; the change requires the boat ashore. On top of that comes the oil service every year.)
• Outboard: compare the engine hours with the expected service life (about 1,000–3,000 engine hours with good maintenance), freshwater flushing after salt water documented?
• Propeller: damage, cavitation pitting, out of true?
• Impeller (cooling water pump): last change documented? (Recommended: every year)
• Fuel hoses and valves: perished, clips rusty?
• Cooling water hoses: age, perishing, clips rusty?
• Engine bearers / engine bed: cracks, corrosion, loose bolted connections?
• Zinc anodes: check their condition. It is normal for them to be worn; if they have almost gone, they will soon stop protecting drive parts and skin fittings from corrosion
• Sailing boats, rig: When was the standing rigging last replaced? Is there an invoice? (Usual on the market every 10–15 years)
• Sailing boats, sails: How old are the mainsail and headsail? (Sails last about 8–12 years)
• Sailing boats with saildrive: diaphragm intact? (A cracked saildrive diaphragm means water in the boat, often overlooked, expensive when it fails) Ask for the date of the last diaphragm change (manufacturer’s requirement about every 7 years)

You will meet the four drive types on the market under different names: sterndrives also as Z-drives or Aquamatic, pod drives under names such as IPS or Zeus. Whatever name is on it, the type stays the same. What separates the types in running costs is set out in Motorboat running costs. On a sailing boat the inboard diesel drives a shaft or a saildrive; what both need in running costs is set out in Sailing yacht running costs.

The rule for this whole block: do not ask about the condition, ask for the date. “Runs well” is no answer; “bellows changed in 2023, here is the invoice” is one.

How to check engine and drive at the viewing and on the sea trial or test sail, step by step: Checking a boat engine.

Block D: Electrics & systems

• Starter battery and domestic batteries: age known, capacity tested?
• Battery charger / shore power system: working?
• Bilge pump: working both automatically and manually?
• Navigation electronics: chartplotter, VHF radio, AIS, check that they work
• VHF radio with DSC distress call: MMSI number present? (DSC registration does not pass automatically to new owners; it must be actively transferred at the relevant office)
• Condition of the wiring and fuse box: outdated or home-installed cables? (Corroded or badly installed cables are a common cause of fires on boats)
• Check connectors for corrosion; a salt-water environment is the toughest test for electrics
• Every fuse labelled, battery master switch fitted, batteries firmly secured?
• Fuel system: shut-off valve, filter with water separator, secure filler cap, hoses free of cracks and firmly connected? (If it smells of petrol or diesel, nothing gets started; on petrol engines also: engine bay blower working?)
• Smoke alarm and CO alarm fitted? (Especially important with a diesel heater or a cooker on board)
• Windlass: electrically working, chain in good condition?
• Gas system: professionally installed, inspection sticker with a valid date and inspection certificate present? Check hoses and regulator for age and condition, and cooker, heater and fridge for function
• Toilets / holding tank: watertight, valves moving freely, hoses free of odour?
• Fresh water: run all taps; does the pressure pump keep briefly cutting in after all taps are shut? (Then there is a leak somewhere)
• Hot water / calorifier: working, age?
• Air conditioning (if fitted): working?
• Navigation lights, anchor light, interior lighting complete and working?

Block E: Safety equipment & registration

• Lifebuoy with line and light: present, line undamaged, light working?
• Liferaft: manufacturer’s certificate up to date? (Service interval: 1–3 years depending on the manufacturer)
• Lifejackets: enough of them, inspection date, automatic inflation intact?
• Fire extinguishers: number, charge level, inspection sticker?
• Distress signals: hand flares, rockets, expiry date not passed?
• EPIRB / PLB: registered, battery and hydrostatic release up to date?
• First aid kit present and complete?
• Abroad: Which mandatory equipment does the cruising area the boat sails in require, and is it all on board? (The list differs by cruising area and flag; the relevant harbour authority can tell you what currently applies.)

Block F: Additional points when buying a share

This block applies only if you are buying a share in an existing co-owner group or forming a new one with others.

In that case you are checking not only the boat, but also the group you are joining and the rules under which you will use the boat together in future. Both have to be right.

Structure & contract

• All future co-owners named in the purchase contract? (Without exception where a group of buyers forms the co-owner group)
• Handover date fixed in writing? (With the handover, the risk of damage generally passes to the buyer.)
• Liability for defects: has an exclusion of liability for defects been agreed? (Usual in a private sale; set it down in the purchase contract. Without an exclusion, the statutory 2-year period under the German Civil Code (BGB) applies.)
• Living Contract (co-owner agreement) in place or in preparation? (Usage times, cost split, standards of care, leaving; without this contract co-ownership is a risk)
• Leaving clearly settled? (What happens if a co-owner wants to sell their share?)

Berth & insurance

• Berth contract: can it be transferred to several owners? Has the marina been informed, and does it agree?
• Boat insurance: can it be extended to all co-owners? Who is liable for what? (Clarify with the insurer before buying; not all policies cover co-ownership without adjustment)

Boat history & finances

• Existing charter commitments? (Current charter contracts and bookings can pass to the new co-owner group; clarify with a tax adviser what follows from that)
• Larger repairs in sight? (For example engine overhaul, osmosis treatment, new sails: are reserves in place or to be planned for?)
• Maintenance history traceably documented? (Gaps in the documentation affect all co-owners, not just you)
• Usage calendar / booking system: is it settled who uses the boat when?

If you buy alone, it is enough to know the boat. When you buy a share, you also need to know the people you will use it with in future, and the rules under which you do so together. As soon as PartABoat accompanies the purchase, it organises these introductions before the purchase.

PartABoat is just starting: listing and enquiries already work. Until PartABoat accompanies the purchase, you buy directly; you then organise getting to know each other and forming the group yourselves. How to secure the purchase price is set out in the information sheet.

Block G: Sea trial or test sail & handover record

You have worked through all the points and the boat stands up to them? Then two more things before you sign.

Sea trial or test sail

Never buy without a sea trial or test sail. What stays invisible ashore shows up on the water:

• Watch the engine temperature under load: does it rise unusually fast?
• Vibration or noise from the drive at different revs?
• Steering: play, stiffness, self-centring? (Check under way, when the forces are greatest; hydraulic steering for leaks)
• Does the engine reach the rev range the manufacturer states at full throttle? (Too low: propeller too large or power missing; too high: propeller too small or damaged)
• Cooling after a longer run under load (on a planing boat, after running on the plane): measure the exhaust manifolds with an infrared thermometer. If there are several manifolds or two engines, are they about equally warm? Can water-cooled manifolds be touched briefly by hand? (Marked differences or manifolds that are too hot show a problem in the cooling system; do not touch the turbocharger)
• Planing boat: does the boat get on the plane promptly without trim tabs? (Test with full tanks and crew; if the stern stays low for a long time, the engine may be too weak)
• Planing boat: tight turns on the plane: hull without sudden hooking, propeller without ventilating? (You can recognise ventilation by the revs suddenly jumping up)
• Sailing boats, on the test sail: can all sails be set, reefed and handed?
• Gearbox under load: ahead, astern, clean transition? (Gearbox damage often shows up only under load)
• Test the autopilot (if fitted) in real conditions under way
• Read all instruments and navigation electronics while under way
• Check the bilge again after the trip: more water than before?

Handover record

Record the handover in writing: all equipment included, the condition of the boat, known defects. Both parties sign. Without a handover record there is no common basis in a dispute.

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