You can do it without a broker, you can do it with the seller's broker only and you can do it with two broker's (see how simple this will be - LOL)
The elements as I see it are
1/ Express an interest in the boat - execute a non-binding sales agreement that allows you to go to the next steps. At this point the sales agreement may require a refundable (conditionally) donwpament.
2/ Establish an escrow - many banks and credit unions offer escrow service
. You put the money
in a bank and the conditions on when and who to the money gets disbursed is established.
2/ Once an initial price
and agreement is in place the sales agreement should specify the terms of survey
and sea trial - how much time you have to do it and what the limits are if any.
3/ Do the survey
and sea trial at your cost
4/ Establish if there are items on the survey that would adjust the value of the boat - negotiate the final price
5/ Execute the bill of sale
and finalize the sales agreement.