Buying a boat
What to Check Before Buying a Used Boat
By The VesselBook Team · Published July 28, 2026 · 7 min read
Check a used boat in this order: identity, paperwork, condition, systems, sea trial — and pay for an independent survey before you hand over money. The order matters. Every hour spent admiring the upholstery of a boat that cannot be legally sold to you is an hour wasted, and every defect found after the money moves is yours.
This is a buyer's working checklist, not a substitute for a surveyor. On anything with an engine, a keel or a five-figure price, hire one.
Identity first
Read the Hull Identification Number off the hull yourself, character for character, and find the hidden duplicate too. Then compare it to the registration or title, the insurance paperwork and the bill of sale. If you have not done this before, here is where to look.
Walk away from — or at minimum, stop and investigate — a boat where the number is missing, has been ground off, is covered by a plate or filler, or does not match the documents. That is not paperwork pedantry. A hull you cannot identify is a hull you cannot insure, register, or resell without a fight.
Paperwork that has to line up
- Title or registration in the seller's name. If the name on the document is not the person taking your money, find out exactly why before going further. "It's my brother's boat" is where a large share of bad boat purchases begin.
- Outstanding loans and liens. A boat can carry debt that survives the sale. For a US Coast Guard documented vessel, an abstract of title from the National Vessel Documentation Center shows recorded mortgages and liens. For a state-titled boat, the state title agency is the place to ask; what is available varies by state, so ask early rather than assuming.
- Yard, marina and storage bills. Unpaid yard invoices can become a claim against the boat, and a yard that is owed money can be very difficult about releasing it.
- The trailer. It is separate property with its own title or registration in most states. Check it separately.
- The bill of sale. Get one, with the HIN on it, the engine serial numbers, the price, the date, and both signatures.
What you can spot yourself on the hull
- Tap and press the deck underfoot, especially around fittings, stanchion bases and hatch corners. A dull, soft or springy feel suggests a wet core, which is one of the most expensive repairs on the list.
- Look along the hull in low, raking light. Ripples, filler shadows, a repair with slightly different gelcoat, or a line of stress cracks radiating from a fitting all tell you something happened there.
- Keel and rudder. On a sailboat, look hard at the hull-to-keel joint for a crack or a fresh smear of filler, and check for play by trying to move the rudder fore and aft. On a powerboat, check the strut, shaft and prop for play, and the skeg for repairs.
- Bilges. Water in the bilge is normal on many boats. Oil, coolant, salt crust, or rust stains running from a specific place are not; find where each came from.
- Corrosion. White powder on aluminium, green on copper and bronze, pitting on stern-drive housings and rust weeping from stainless fittings. Pay attention to anything below the waterline.
- Rigging age, on a sailboat. Standing rigging has a service life, and insurers frequently want it replaced past a certain age. Look for cracked swages, broken strands at terminals, and rust stains at the tangs. Ask when it was last replaced, and ask for the invoice.
Engine and systems
- Hours and service history. Ask for invoices, not memories. A boat with a folder of receipts is worth more than an identical boat without one, and the folder is also the honest record of what has already failed.
- Cold start. Insist on starting the engine cold, and be there for it. A pre-warmed engine hides hard starting, smoke and noises.
- Compression test and oil analysis on any significant inboard or outboard purchase. Both are cheap relative to an engine.
- Fuel system. Tank age and material, hose condition and date codes, filters, and any smell of fuel in an enclosed space.
- Electrical. Batteries and their age, corrosion at terminals, added wiring that does not match the factory work, and whether the shore-power system has an ELCI or GFCI protection. Amateur wiring is both a fire risk and a fair indicator of how the rest of the boat was treated.
- Steering and controls. Full lock to lock, feeling for stiffness or play.
Safety gear and its expiry dates
In US waters the Coast Guard requires current gear, and expired gear is both a citation and a real risk. Check dates while you are aboard:
- Pyrotechnic visual distress signals expire 42 months after their date of manufacture.
- Disposable, non-rechargeable fire extinguishers expire 12 years after their date of manufacture; rechargeable ones need periodic servicing.
- Life jackets must be in serviceable condition, the right sizes for the people aboard, and accessible.
- EPIRB or PLB battery and registration, and liferaft service date, if the boat has them.
None of this is expensive to replace, but it all adds up, and it belongs in the price conversation.
The sea trial
Do not skip it, and do not accept a five-minute run in the harbour. You are looking for: does she reach expected cruising and wide-open-throttle RPM, does she hold temperature and oil pressure, does she track straight, does she steer without vibration, what does the bilge look like after an hour, and do the electronics work under way rather than at the dock.
Bring your surveyor if you can. A sea trial with the surveyor aboard is where a great many quiet problems announce themselves.
Pay for a survey
Hire a surveyor who works for you, not one recommended by the seller, and one who is accredited — in the US, that usually means SAMS or NAMS. Expect a haul-out for the underwater inspection, and expect a written report with findings, moisture readings and recommendations.
Two practical notes. First, your insurer will very likely require a recent survey, so you are probably paying for one regardless. Second, the report is a negotiating document as much as a decision document: findings become either a price adjustment or a list of things fixed before closing.
Ask for the record trail
There is no national accident-and-claims database for boats that a consumer can simply search, the way a car buyer can pull a report. Boat history lives in scattered places: the seller's invoices, the yard's files, past surveys, insurance records. So ask directly, and notice how the seller responds to being asked.
VesselBook exists to make that trail less scattered. The free HIN Lookup shows what is publicly on file for a hull, and boats listed on VesselBook can carry their documented history — surveys, verified work, ownership verification — attached to the hull rather than summarised in a sales paragraph. You can see what a full history report looks like before you ask a seller for one.
An empty record is not proof of a bad boat; most hulls simply have nothing on file yet. But a seller who has kept and can hand over the history has told you something real about the boat, and about themselves.
The short version
- Read the HIN off the hull and match it to every document.
- Confirm the seller can legally sell it, and that nothing is owed against it.
- Walk the hull, deck, keel, rudder and bilges yourself.
- Cold-start the engine, then test compression and oil.
- Check every expiry date on the safety gear.
- Sea trial for at least an hour.
- Pay your own accredited surveyor, and read the report before you pay the seller.
- Collect the paperwork — and keep it, because you are the next seller.