A Yacht Clearinghouse is different than a broker, and every boat will (should) have one. The Yacht Clearinghouse role is to be a go-between the boat and the broker. They also help with positioning the yacht in the market, so it receives bookings! Many years ago, boats did not have the communication technology when they were out on the seas, and the yacht clearinghouse would keep all the details of each boat they represented and answer questions.
They hold the calendar, which is quite important so the yacht is not double booked.
The clearinghouse also arranges to have an escrow account for the money and pays it out to the yacht owner at the correct time. There are many Yacht Charter Brokers, not as many Clearinghouses, and they tend to be somewhat in the background of the industry, although some do have Yacht Charter Brokers that work in their offices.