Thanks blue_water, our NCL ship arrives in Tortola at 8:00 am. I'm not sure if I can make the 8:30 am outbound Sensations ferry time. I even thought about taking the outbound Speedy's at 9:00 am, and the return Sensations ferry at 1:45 pm. The times would be perfect, but now I'm scared about taking two different ferries, and if it would complicate my journey. I decided to just bite the bullet and buy the NCL ship excursion. Thanks for your help.