Buying guide

The used boat buying checklist: what to find out before you pay for a survey

Vessel Forensic · 15 July 2026

A marine survey is the right way to finish buying a boat. It is the wrong way to start. A survey costs serious money, happens late in the process, and tells you what is broken on a boat you have already fallen for. The expensive mistakes happen earlier: choosing the wrong boat for the mission, trusting a listing that leaves out the history, and paying an asking price that ignores what the next three years will cost. This checklist covers what to establish before the surveyor is ever instructed.

1. Fix the mission before the boat

Write down what you will actually do with the boat: coastal weekends, a trade wind circuit, a liveaboard life, watersports, long range passages. Then hold every candidate against it. A fin keel and spade rudder are a fine choice for coastal sailing and a known risk for ocean crossings. A planing hull suits watersports and punishes long passages at the fuel dock. Most bad purchases are not bad boats; they are good boats bought for the wrong mission.

2. Establish the boat's identity precisely

• Exact make, model, and mark or series. A Mark I and a Mark III of the same name can be different boats.
• Year built, not year registered.
• Hull material, keel type, rudder configuration, rig or drive type.
• Engine make, model, and hours. If the listing does not state hours, ask why not.

With the identity fixed, the boat's design history opens up: what it was built for, its known weaknesses, and the problems owners of that exact model report.

3. Age every major system, not just the hull

A thirty year old boat is not one purchase. It is a hull plus twenty or more systems, each with its own design lifespan and replacement cost. Standing rigging is typically a ten to fifteen year item, and many insurers refuse offshore cover beyond that. Sails, batteries, hoses below the waterline, through-hull fittings, electronics, autopilots, and life rafts all age on their own clocks. For each system, the question is the same: when was it last replaced, and what does replacement cost at market rates today? Anything the seller cannot date, assume is original and price accordingly.

4. Extract the history the listing leaves out

Listings are marketing. Ask the seller, in writing:

• Has the boat ever grounded, or suffered keel, rudder, drive, or propeller impact?
• Any osmosis, blistering, or hull repairs?
• Where has she been kept: marina, mooring, or hard standing?
• When was the last survey, and may you see a copy?

An honest unknown is more useful than a guess, and a seller who will not answer in writing has answered anyway.

5. Price the ownership, not the purchase

The asking price is the entry fee. The real number is asking price, plus overdue replacements, plus what falls due within your ownership window, plus running costs every year: insurance, berthing, fuel, and routine upkeep. Set an estimated resale value against that total and you have the true cost of the boat. On older vessels the overdue work alone can rival or exceed the asking price, which turns a bargain listing into the most expensive boat in the marina.

6. Set your maximum offer from the deficit

Add up the overdue and critical replacements at yard rates, add a margin for the disruption of the work itself, and subtract the lot from the asking price. That figure is your ceiling, and the itemised list behind it is your negotiating position. If the ceiling comes out below zero, the correct offer is no offer at all.

7. Then, and only then, commission the survey

A survey on a boat that has passed everything above is money well spent: the surveyor confirms condition, catches what paperwork cannot, and satisfies the insurer. A survey instead of the steps above is a four figure fee to learn you should have walked away a fortnight ago. Nothing here replaces a qualified marine surveyor; it makes sure the boat deserves one.