The initial deposit at the time an offer is made is up to the prospective buyer, only. Typically a few thousand dollars depending upon the cost of the yacht. The deposit is normally increased to an amount sufficient to cover the costs of a haulout and survey if an offer, subject to the survey, is accepted to cover the possibility that a prospective buyer may disapprove the survey and then be unable or unwilling to pay the costs of same. (I have seen this happen when a survey revealed conditions that a seller could not but have known about but failed to disclose to the prospective buyer. The buyer's position was that the failure to disclose was a material breach of the rule of good faith and fair dealing and that had the seller made the disclosure, the buyer would not have gone ahead with the cost of the haul and survey. Frankly, I agreed with the buyer's position but his deposit covered the costs and they fought it out later). Once the survey is approved and the sale is agreed upon and contingencies waived, the good faith is normally increased by a material amount which is non-refundable should the buyer fail to close for any reason other than a material change in the condition of the yacht. If so, the non-refundable compensates the broker for his work; and, the seller for the cost of having the yacht off the market. Some hold that the time off the market is not material but I have seen cases where a prospective buyer shows up days after an offere is made, discovers that the boat is in contract, and goes off and buys his/her second choice only to learn later that the original boat comes back on the market due to some issue between a seller the the first buyer.
"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."