The email below is very typical of a "Nigerian dud check, overpayment" scam. They are VERY active on sites like Ebay and Craigslist and are now VERY active on the boating market.
I am emailing to confirm the acceptance of your offer since everything sounds good.
I also want to use this opportunity to inform you that I will be out of town until 07/30/2007 but I have left instructions with my banker regarding your payment.
I made arrangment with a transport/shipper agent who will come to pickup the boat but I've not heard from him for couple of days now and I have tried to communicate with him through his secretary but I was informed that he is on asignment so I adviced my banker to include the agent's payment in your cashiers check so that when you receive the cashiers check,you can advance his fees to him.
He will send you $15,000 cashiers check which I will require you to deduct $6,000 as your payment and forward $9000 to him via western union/moneygram so that he can come and inspect the boat. I will send you his contact information so that you can be able to make arrangment with him for the excercise.
Please provide the following data so that the payment check can be sent to you via FEDex.
Contact phone #...........
Waiting for your urgent answers.
The check will arrive, your bank will accept it, you will happily "refund" the overpayment. Your bank could take up to 3 months before they inform you that the check that you deposited is fraudulant. You have to refund the bank AND you have lost the "overpayment" refund that you sent to the "buyer". You may also have lost the boat or goods that you "sold" and were collected by the "buyer's agent".
The alarm bells must ring as soon as you see Western Union or Moneygram - these payments cannot be traced after collection as the receiver gets the money by only quoting a sender's document number and password, both which you must supply him by email after "sending" the money. The receivers personal ID is not required to collect. EVERYTHING LOST!
You may also have a rough time explaining to your bank and possibly law enforcement why you deposited a fraudulant check.
NEVER give your real details to these scammers - they are routhless!
PLEASE BE WARNED.
See: http://www.419eater.com (see their Forums) for more details.