RedactedNarrative: Vessel #1 was underway on Lake Michigamme with 4 occupants.  All occupants advised that they heard a loud clunk. The transom started to separate from the vessel, and the boat started to take on water and sank.  Occupants advised that the vessel sank very quickly.  Three occupants put on life jackets and the fourth could only put it around his neck region.  No other injuries or damages were reported.