RedactedNarrative: Operator report only (limited information)
  As I approached the lock/dam from the south in the main channel, I radioed the dam operator and was told that a barge was approaching the lock from the north.  I told the operator I would turn around, head south and return the following day.  
  
  I idled the engine while speaking to the dam operator for about 30 seconds.  Before I could engage the engine and move forward, the rear props struck a submerged rock wall, rendering the boat temporarily inoperable.  
  
  Conservation Warden approached the vessel in his vessel and rendered immediate assistance.  My vessel drifted backwards over the submerged rock wall.  With the warden's assistance, and one propeller working I was able to navigate the vessel to a nearby sane beach, docked it, and all the passengers were safely evacuated to the Wisconsin shoreline by the warden's team.
  