Sadly, day sailing is something that is lacking on Tortola and the BVI in general. Blue Rush Water Sports at Leverick Bay has a Hobie Cat for rent.

Other than that, you might try BVI Yacht Charters. "IF" they have a boat on the dock, they may do a deal with you for a day or two. They used to do that ... not sure if they still do but it's worth a shot. Call them at 494-4289.