What a marine survey actually covers, and what it misses

A pre-purchase survey is the best money you will spend buying a boat, and it is also routinely misread. Buyers treat a clean report as a guarantee and a long findings list as a disaster. Neither is right.

What a surveyor is actually doing

A pre-purchase survey is a condition and valuation inspection. The surveyor is establishing what the boat is, what state it is in, and what it is worth, in enough detail that you and an insurer can both rely on it.

On a typical hull that means: moisture readings through the hull and deck, a hammer sounding of the laminate, the structural bulkheads and stringers where they can be reached, through-hulls and seacocks, the steering and control systems, the electrical panel and wiring, safety equipment, and the fuel system.

On a haul-out, which you should insist on, they see the running gear, the shafts and struts, the rudders, the props and the bottom paint. Most of the expensive surprises live below the waterline.

What a survey does not cover

This is the part that catches people out.

Engines are usually a separate survey. A hull surveyor will note the engines and their obvious condition, but a proper engine survey by a diesel or outboard technician, including oil analysis and a diagnostic scan, is a different job with a different bill. On any boat where the engines are a meaningful share of the value, have it done.

A surveyor does not dismantle anything. They do not pull headliners, lift bonded floors or open sealed compartments. What cannot be seen is not surveyed, and a good report says so explicitly.

Tankage is often inaccessible. Fuel and water tanks under a bonded sole frequently cannot be inspected at all.