Two ferries means that we can use the most efficient boat for the number of riders (this is one reason it's really helpful to be at the dock 10 minutes before departure: that's when the captain selects the most cost-efficient boat to run.) That is why you need to call the ferry on the return trip to the Isle of Palms: in order to assure you a seat on the boat. Please tell the captain how many people, dogs, and luggage carts to expect.