A funayuhrei is in Japanese folklore, a Ghost ship that travels silently at night or in thick fog. It appears suddenly without sound or lights. Meeting one on the sea is fatal. The appearance of a funayuhrei will cause a ship to start to turn violently in circles and then sink. The doomed ship then becomes a funayuhrei itself. As for the victims, if they are lucky, they drown. If they are unlucky, they might be captured, tortured and eaten by the isohime, a giant, fantastical mermaid that likes to catch the survivors of sinking ships.
The Encyclopedia of Ghosts and Spirits – Written by Rosemary Ellen Guiley – September 1, 2007