Macedonia ? An overloaded sightseeing boat carrying dozens of Bulgarian tourists sank Saturday in a lake on Macedonia’s western border, and 15 people drowned, officials said.

The vessel, called the Ilinden, sank rapidly in just six meters 20 feet of water in Lake Ohrid, police spokesman Ivo Kotevski said. The vessel split in two and sank about 650 feet from shore.

There were 57 passengers on board, Kotevski told The Associated Press. Of those, 15 drowned and 42 were rescued. Four passengers who were recovered unconscious are still in hospital but are not in danger, he said.