RedactedNarrative: Operator of a boat that was motoring north on Holter Lake after departing from Gates of the Mountains Marina.  While operating at planing speed, operator attempted to address some equipment issues with his boat and was distracted from driving.  The boat turned to the left while operator was distracted, and was bearing straight for the west shore of the Holter Lake just north of Colter Campground.  Just prior to hitting the shore head-on, operator made a evasive turn to the right.  The boat slid and impacted the shore on its port side.  operator was thrown to the floor.  victim was an occupant in the rear of the boat, and there was injury to his arms and some internal injuries.  victim died from his injuries the following day at  St. Peter''s Hospital in Helena.