Adrift on St. John by Rebecca M. Hale
the first book of the Mystery in the Islands Series
No one knows better than resort manager Pen Hoffstra that the idea of a tropical paradise is an illusion. So when a young woman named Hannah Sheridan disappears off the island of St. John, she is not surprised that all is not what it seems to be. Pointing out Hannah's resemblance to the Amina Slave Princess from the 1733 slave revolt on St. John--whose ghost is rumored to haunt the island--the local community quickly latches on to the belief that her spirit is behind the sinking and the disappearance...
This is a great book! Check it out if you haven't already!