What other expenses will I have?

It depends on your destination.  For example: in BVI, you will be responsible for BVI park fees which, all together will run you about $8 per person, per day. This permit will provide you with daytime mooring in restricted areas. Fuel for the boat is not included. You are responsible to bring the boat back with full tanks, diesel and outboard. Check fuel levels before departing. You will be responsible for the costs of mooring balls. You’ll always find a place to drop your anchor for free but it may not be as convenient as mooring balls.