If you're going to St. Croix, especially in a Cat; first motor E to St. Johns, preferably Coral Cove area. You'll be fighting a heck of a west flowing current and even if you think you have a beam reach or close reach to St. Croix you'll end up close hauled because of the current.

Have Fun,
Just so you know, you won't be in the "Charterers Paradise" then. Also make sure your charter company allows St. Croix. There is some ocean there and it's not like sailing in Drakes Channel.

Go Slow
Sail Far
Stay Long