A 29-foot boat crashed into a concrete base that supports a utility tower in the middle of a bay, killing four people and injuring five.

The water in Sandusky Bay was about 10 feet deep where the accident happened late Saturday night. There were no reports of fog or rain.

A flashing beacon is atop the tower and a lighted “danger” sign is mounted on its base, said David Roseler, a watercraft officer for the state Department of Natural Resources.

The boat, which was carrying 11 people, crashed about a half-mile from the shore.

The cause of the crash had not been determined.