I'm biding in a boat from US and i live in Canada, not sure about the duty and taxes,Never did this before how much down is thge norm, and when I see it what if it is not what i wanted.
There is no duty if the boat was manufactured in Canada, US or Mexico , otherwise 6-9 %. GST/HST and provincial taxes charged as applicable to your province. Here are some links..
Listing should state deposit requirements or contact the seller. A major purchase should be inspected/tested before final payment and taking ownership.