When you enter a boat into the Local Booking Manager by default it does not have any sort of priority in which the system list them, but you do have the ability to set the order in which the system should list your boats with sort priority function.
When you enter the boat in the list in Work > Yachts the sort priority is set as 0, so select the boat you want to change the sort priority on (1.), enter the numerical value in the Sort priority field (2.) and press Apply (3.).
It would be recommended that you do not enter the sort order sequence as 1, 2, 3...., but to leave space between sort priority numbers like 10, 20, 30..... in case you need to insert the boats in the future so you do not have to change priority for all the boats.