Ghost ship - Mary Higgins Clark

Thomas loves his summer visits to his grandmother's on Cape Cod. He spends his days wondering about the sailing ships of the past and imagining their stories.
One afternoon, after a night of terrible thunderstorms, Thomas finds, deep in the sands, a weathered old-fashioned belt buckle. When he picks it up, a boy his own age appears before him. His name is Silas Rich, a cabin boy from a ship called the Monomoy that sailed almost 250 years ago. As Silas tells his tale, suddenly the world of sailing ships is very near indeed.