There are several scams on ebay but the boat scam is a tough one to spot. I was suprised one day when my boat was for sale! Someone had used the same ad from when I bought my boat same pictures and everything. I also found it listed on another site. Ignore the feedback score. Many of these are sold on hi-jacked accounts with good feedback.

Sometimes there is a buy it now that does not work or they are getting divorced ect. Never send anyone money for a boat that you are not sure is actually there. Ask them to take it to the local boat dealership or whatever but don't even send a deposit. Noone ships a boat for free anywhere in the US. Beware of any auction at all even the ones that seem legit. Many people have sent a deposit only to find the seller slip away. Usually this is because they hijacked a user-name with good feedback copied a completed listing and sit back and wait for the deposits to come in. Please report it to the police if you are involved and e-bay even though they can't do anything. This is the same advice for cars.