How do i check if a boat has been in an accident?

If it’s a pricey investment, get it surveyed. (That’s like getting an inspection on a house you want to buy.) A professional surveyor is very thorough, and can spot almost any problem you might have.

Welcome to Fluther.

Welcome to Fluther.

What @JilltheTooth said. The person you’re looking for is a “Marine Surveyor”. I don’t know how or if that person is certified or licensed, but those would be good questions to ask him, as well as his insurance and guarantee. (Because if he misses something important you need more than just a shrug of the shoulders and, “Oh, well…”)