If you buy a boat through a seller's
broker, they will likely have their standard operating procedures concerning
contract, down payment, escrow, etc. The
broker will likely send you an offer form/contract. It's your offer, so you will be able to fill in the offer amount and time line between survey/sea trial to acceptance, etc. Make sure this is reasonable, realizing it may take a few days longer to get the survey back than promised.
If it's a boat
for sale by owner, you will need to write up your own offer/contract. You will need to decide on an escrow or good faith with potential seller. For me this decision would depend on the amount of
money involved. For a
pocket cruiser, I've had no problem sending 10% to the seller knowing small claims court would be my likely fall back if the deal fell through and if the seller did not refund the deposit.
Check into
insurance,
storage options, etc. before you make your offer. Rather than rely on guesstimates here, just call
insurance companies and boat yards/marinas you are likely to use and ask. Same with transportation. Get a quote.
In the U.S., local
registration is usually handled by your county courthouse, either by the DMV or the office of the registrar. Again, call them to ask what you need. Probably the former registration certificate and title signed over to you by the previous owner as well as proof of the purchase
price.
I recommend making a detailed list of things to look through when you look at a boat and force yourself to stick to it. Get the owner/broker off the boat for your
inspection even if they are just standing on the
dock. Bring a knowledgeable friend who is not as invested in your purchase as you are. It's easy to loose your objectiveness at this stage.
Be prepared to walk away at any stage, even if you've paid for a survey. I did that twice with my last boat search. It's hard, but worth it in the end.
P.S. - I see you have "China" listed as your location. If this is where you are
purchasing your boat, the registration and tax issues will likely be different.