RedactedNarrative: On May 29th, 2022 at approximately 11: 45PM a 1989 Scarab Panther being operated by subject sunk in the Missouri River with 10 other individuals onboard the vessel.  All individuals on board the vessel were able to get on another boat that was traveling with vessel except one person.  The victim had a .189 BAC.  The operator had a .062.  The vessel was operating in very rough conditions.
  
   It is unknown if the vessel being stuck contributed to the rubber bellows being mostly missing or  the condition of the Operator played a contributing factor. 
  
  A representative from Mercury Marine discovered the following: The port side drive had damage in the area of the outer transom plate where the drive shaft rubber bellows are located.  The Gimbal bearing was severely damaged, and the rubber bellows that enclose the drive shaft (provides the watertight seal for the driveshaft) was mostly missing. In addition, the rubber element of the engine coupler mounted to the back of the flywheel was completely separated from the mounting plate.
  
  The gimbal bearing is needed to hold the drive shaft in alignment between the engine coupler and the upper gear input of the drive. When the bearing comes apart, and pieces are displaced, the U joint will rotate in an elliptical rotation and contact the rubber bellows. This tears the bellows and water will enter the engine compartment through the space formerly occupied by the bearing. 
  
  The elliptical motion of the shaft placed significant strain on the engine coupler, that is intended to provide torsional dampening and a nominal amount of misalignment. It is normally aligned with the centerline of the gimbal bearing and the centerline of the coupler. In the case of this event, the degree of the shaft deflection exceeds the couplers ability to transmit torque thru the misaligned shaft. This caused the rubber within the coupler to shear, and the drive shaft to the drive then became completely disconnected from the engine. This would stop all power from the drive and appear to the operator as a failed engine, which operator stated had happened.  Representative also stated that this is a maintenance issue and should be on a regular maintenance schedule.
  