It is about a half hour car ride from the cruise dock to the Red Hook ferry, but that might not be necessary. There is a ferry that leaves right from Charlotte Amalie close to the cruise terminal. This one might be more convient. Here is the schedule for both ferries:
BETWEEN RED HOOK, St. Thomas and CRUZ BAY, St. John
Transportation Services (340) 776-6282
$3 one way, children under 12 $1, Seniors $1.25 15 to 20 minute ride Daily
Leaving Red Hook 6:30 am and 7:30 am - Then hourly 8 am to midnight
Leaving Cruz Bay Hourly 6 am to 11 PM
BETWEEN CHARLOTTE AMALIE WATERFRONT, St. Thomas and CRUZ BAY, St. John
Transportation Services (340) 776-6282
$7 one way, children under 12 $3, Seniors $5 45 minute ride - Daily
Leaving Charlotte Amalie 9 am, 11 am, 1 PM, 3 PM, 4 PM, 5:30 PM
Leaving Cruz Bay 7:15 am, 9:15 am, 11:15 am, 1:15 PM, 2:15 PM, 3:45 PM