Ferry dock is the one in CA which is where most people embark for trips to the BVI. The last ferry of the day leaves from Red Hook. I haven't taken a water taxi but a taxi ride from the airport to Red Hook is probably quicker, and less expensive, that getting a water taxi at CA and heading down the coast, past Red Hook to get to the BVI. In our 2018 trip we purchased the Moorings transfer package ($90 a person) which included the taxi rides and a round trip ticket on the Fast Ferry and it worked well getting us to the base sometime around 6pm I believe. We'll probably do that again on our 2020 trip.