What happened
During a flight involving a passenger, the pilot attempted to demonstrate an intentional stall maneuver. While executing a left turn with approximately 15 to 20 degrees of bank, the pilot configured the glider into a stall. During this maneuver, the aircraft stalled with the nose and the left wing dropping.
The aircraft subsequently entered a spin. The pilot attempted to recover by applying full-forward stick input and full rudder deflection opposite the direction of rotation. These recovery efforts were unsuccessful, and the aircraft impacted a lake.
Following the impact, the fuselage remained afloat long enough for both the pilot and the passenger to exit the aircraft and swim to shore. The aircraft then sank in approximately 200 feet of water. There were no injuries reported.
The investigation
The pilot reported no mechanical malfunctions or failures occurring prior to the impact.