Vessel #1 was coming up on plane from a slow--no wake zone when the vessel struck a partially submerged "dead head".  As reported by witnesses, Operator of Vessel #1 struck a second vessel, ejecting it's operator and passenger.  He then came to rest and quickly sank.  A witness vessel pulled Operator and passenger of Vessel #1 from the water and took them to the Rust Ave. Boat Launch.  A second witness vessel secured the pilotless second vessel and rescued the two occupants and returned them to their boat. They then quickly left the scene.  No information regarding the second vessel, except is had stern damage on the starboard side.
Vessel was pulled from eh river by Mike's Wrecker of Saginaw on 8/11 per DNR and USCG request.   No information of second vessel could be obtained, not even after several interviews with witnesses.
City of Zilwaukee             