What to check when buying a used boat.

For owners · 28 September 2026

Most people buy a boat with their eyes. It is clean, it is shiny, the seller is pleasant and the sun is out. Then the survey comes back and the number at the bottom is the price of a small car.

You cannot survey a boat yourself, and you should not try. What you can do is walk it properly before you spend money on a surveyor, and find the boats that are not worth surveying at all. That is what this is for.

Go when the engines are cold

Ask that nobody starts the engines before you arrive. A warm engine hides a hard starter, a smoking exhaust and a charging fault, and the ten minutes somebody spends warming them up for you is ten minutes of information you will never get back.

If you turn up and the engines are already running, that is not proof of anything dishonest. Come back another day anyway.

The engine room tells you about the owner

You are not there to judge the engines. You are there to judge the person who owned them. Open the hatch and look at the things nobody cleans for a viewing:

• Under the engines, not on top of them. A wiped rocker cover means somebody wiped it. Oil pooled underneath means a leak nobody fixed.
• The color of the water in the bilge. Clear is fine. A rainbow film is fuel or oil. Milky is worse and worth asking about.
• Hose clamps. Two on every hose below the waterline, both stainless, neither weeping rust. Rust streaks under a clamp are a boat that has been left alone.
• The strainers. Clear bowls, no growth, lids that have obviously been off recently. Somebody who services strainers services other things.
• Wiring. Original looms are tidy. Later additions tell the truth: household connectors, tape instead of heatshrink, a fusebox added with wood screws.

Water is the enemy, and it leaves marks

Every boat gets wet. The question is whether the water is getting somewhere it should not, and staying there.

Press the deck, especially around fittings, stanchion bases and the corners of hatches. It should feel solid underfoot with no give and no dull thud. Soft spots mean water in the core, which is a repair measured in weeks rather than hours.

Inside, look up. Stains on the headlining under a window or a hatch are a leak somebody stopped looking at. Open a locker in the bow and put your nose in it. A boat that smells of damp has been damp for a long time.

Ask for the paperwork before you ask for the price

The single most useful thing a seller can hand you is a record of what has been done to the boat, with dates. Not receipts in a carrier bag: a history. Engine services against hours, impellers, anodes, batteries, standing rigging if the boat has a mast.

Most sellers cannot produce one. That is not necessarily a bad boat, but it changes what you are buying: you are buying the boat without knowing when anything was last done, so assume everything is due and price it that way.

When somebody can produce one, read the gaps. A boat serviced every year until two years ago has a story, and the story is usually that somebody stopped using it.

Run the boat, and watch the meters rather than the horizon

On the water, nobody looks at the instruments because the boat is moving and that is exciting. Look anyway.

• Water at both exhausts within ten seconds of starting each engine. If it does not come, shut that engine down.
• Temperature and oil pressure settled and steady, and the same on both engines. Twins that disagree are telling you something.
• Full throttle, briefly. The boat should reach the revs the engine maker specifies. An engine that will not is either tired, overpropped or fouled, and all three cost money.
• Hard turns both ways and a look behind for smoke as the boat comes on the plane.

The four questions worth asking out loud

1. When was the boat last hauled, and can I see the photographs?
2. What has been replaced in the last three years?
3. What is on the list that has not been done? Every boat has one. If an owner says "nothing", ask again, item by item.
4. Why are you selling the boat? Not because the answer is reliable, but because the pause before it sometimes is.

Then pay for the survey

Everything above is what you do so you only pay for one survey instead of three. It is not a substitute for one, and nothing you see on a walk round can be: a surveyor carries a moisture meter, a hammer and the standing to write something an insurer and a lender will accept.

Use your own surveyor, not one the seller recommends, and be aboard while they work. The hour you spend following a surveyor round a boat teaches you more about the boat than the report does.

And after you buy the boat

The reason a used boat is hard to judge is that nobody wrote anything down. Whoever looks after the boat next can fix that for the next owner, whether that is a yard, a captain or you.

That is the whole of what we build: a checklist built from what is actually aboard it, a score you can take apart, and a report with photographs and a date on it, so that in five years somebody standing where you are standing today can see exactly what was done to the boat and when.