The Eyes of the Amaryllis

When the brig Amaryllis was swallowed in a hurricane, the captain and all the crew were swallowed, too. For thirty years the captain's widow, Geneva Reade, has waited, certain that her husband will send her a message from the bottom of the sea. But someone else is waiting, too, and watching her, a man called Seward. Into this haunted situation comes Jenny, the widow's granddaughter. The three of them, Gran, Jenny, and Seward, are drawn into a kind of deadly game with one another and with the sea, a game that only the sea knows how to win.
The Eyes of the Amaryllis is a 1977 New York Times Book Review Notable Children's Book of the Year.