You work as an investigator and you are chasing a fugitive criminal, and you have learned that the criminal uses a boat to escape, and you know the specifications of that boat, but after searching, you did not find the boat, knowing that no boats came out of the city... How did the boat disappear?
The most likely outcome it that either intentionally, or unintentionally, the boat was sunk. This scenario often happens by a means of escape and total disappearance. Another likely outcome is the boat could be hiding in swamp areas.
