By The Saltwater Insider Crew

A used boat will tell you almost everything about its life if you know where to look. The trouble is that most buyers look at the wrong things — the upholstery, the electronics, the way it looks backing off the trailer — and skip the handful of checks that actually separate a good buy from a five-figure lesson.

Here are ten, in the order we would do them.

1. The paperwork, before the boat

Confirm the seller is the owner. Match the name on the title or Certificate of Documentation to the person you are talking to.

Check for liens. A boat with an outstanding loan is not the seller’s to sell free and clear, and you do not want to discover that after money changes hands. State titling and USCG documentation are different systems — know which applies to the vessel you are looking at.

If the paperwork is not clean and available, that is the answer. Walk.

2. The Hull Identification Number

Find the HIN on the transom, starboard side, and confirm it matches the paperwork exactly. Photograph it.

A HIN that has been altered, obscured, or does not match the documents ends the conversation. There is no innocent explanation you need to hear.

3. Stringers and transom

This is where the money is. Structural moisture in the stringers, bulkheads or transom is the difference between a boat worth buying and a boat worth avoiding entirely.

Look for cracking or crazing where the stringers meet the hull. Check the transom for flex — with the outboard trimmed, that area should feel solid, not springy. Soft spots underfoot on deck indicate wet core.

You will not fully diagnose this yourself. That is what the surveyor is for. But you can spot enough to decide whether to spend survey money at all.

4. Corrosion, everywhere

Saltwater keeps an honest record. Open every locker and look at the fasteners, the hose clamps, the through-bolts, the bonding wires.

Heavy corrosion on hardware in places nobody sees tells you how the boat was rinsed, stored and maintained — which tells you about the parts you cannot see.

Pay particular attention to any dissimilar metals in contact, and to the condition of the anodes. Anodes that have never been changed are a story all by themselves.

5. Engine hours, and what they mean

Hours matter, but context matters more. A high-hour motor with complete service records, clean fuel and consistent care can be a better bet than a low-hour engine that sat neglected for years.

Ask for the service history in writing. Ask who did the work. A seller who can produce records has usually earned the benefit of the doubt; a seller who cannot has told you something too.

6. Compression and diagnostics

Do not take anybody’s word on engine condition, including your own ears.

A general pre-purchase survey typically does not include a full engine survey. Internal condition, compression testing, oil analysis and diagnostic scans are usually a separate specialist. On a boat where the propulsion is a large share of the purchase price, hire that specialist. It is the cheapest insurance in the transaction.

7. Fuel system

Look at the tank, the fill, the vent, the hoses and the clamps. Ethanol has been hard on older fuel systems, and hose that is not rated for current fuel blends degrades from the inside where you cannot see it.

Check whether there is a water-separating filter and when it was last changed. Ask whether the tank has ever been replaced or opened. On many hulls, tank replacement is a major structural job because the tank went in before the deck did.

8. Electronics age, honestly assessed

That impressive-looking helm may be less of an asset than it appears. Marine electronics have a service life, manufacturers stop supporting older units, and chart cartography goes stale.

Note the model and generation of each unit. A ten-year-old multifunction display is not a selling point, it is a future line item.

9. The trailer, if it comes with one

Buyers routinely inspect a boat carefully and then accept the trailer sight unseen.

Check frame corrosion, especially at welds and at the tongue. Check the bunks and rollers. Check the coupler, safety chains, winch strap and lights. And check the bearings — grab the tire at top and bottom and shake it, looking for play, and pull a dust cap to see whether the grease is clean or milky.

A trailer that needs axles, bearings and a winch is real money you did not budget.

10. Survey contingency and sea trial, in writing

Make your offer contingent on a satisfactory survey and sea trial, and put it in the agreement. Hire your own accredited surveyor — SAMS-AMS or NAMS-CMS — and pay them yourself.

Be aboard for the sea trial. Run the boat through its range, not just to plane and back. Watch temperatures, listen at cruise, check that everything electrical works while the engine is running.

The mindset that saves you

The boat you walk away from costs you nothing. The one you talk yourself into costs you all season.

Go in expecting to find problems, because you will find them on every used boat ever built. The job is not finding a perfect boat. The job is knowing precisely which problems you are buying and what they cost to fix.

This article is general guidance and not legal, financial or survey advice. Titling, documentation and lien requirements vary by state and by vessel. Retain your own accredited surveyor and, where appropriate, qualified legal counsel before completing a purchase.

See you on the water.