Did a little more research. Crown Bay must be west of the regular dock. According to a VI website the cab ride from the regular dock to Coki Beach is 12 minutes, whereas it's 26 minutes from Crown Bay. However, it's only $1.00 more. The dive center has a dive leaving at 11. I thought I might catch that one. But with a half hour cab ride that doesn't seem too likely. They have another at 1:00 PM.
BTW, the nine day forecast was calling for partly cloudly (little icon on screen showed more clouds than it did the day before) with a temp of 74.