7.
The Baychimo
This ship is a true mystery. It was a steel ship that weighed in at 1,322 tons and as it steamed along it got stuck in an ice pack in October, 1931. The ships crew waited out a blizzard in a wood shack and when the blizzard was over the ship was gone. They assumed it had sunk, but it was seen 45 miles away and for the next 38 years it shows up randomly floating alone and crewless.