Quite often the Paypal scam involves the 'buyer' using someone else's stolen Paypal account details to pay for your boat. They obtain your boat (or quite often car) and when the scam is found out, you are debited the amount which was previously stolen from someone else's Paypal account, and you are therefore without your boat or car, and subsequently without your funds they used to pay for your boat or car.
Don't sell by paypal. This is one of the dodgiest tricks around at present.
Like others have said, if they are genuine they will come and look at the boat.
