The pilot/owner of the airplane stated that after a preflight inspection and before-takeoff checks revealed no anomalies, he initiated a soft-field takeoff from the turf runway. At an airspeed of 50 knots during the takeoff roll, the airplane became airborne after traveling over a “deep dip,” then settled back onto the runway. The airplane then “swerved” to the left, and the pilot attempted to correct with aileron and rudder inputs. The airplane departed the left side of the runway, and came to rest about 300 feet beyond the runway's edge. Examination of the wreckage revealed substantial damage to the left wing, empennage, and tailcone. Examination of ground scars and the tailcone revealed damage consistent with dragging of the tail section on the runway. The pilot reported there were no mechanical deficiencies with the airplane that would have precluded normal operation. According to Federal Aviation Administration Publication FAA-H-8083-25A, Pilot’s Handbook of Aeronautical Knowledge: “The effect of torque increases in direct proportion to engine power, airspeed, and airplane attitude. If the power setting is high, the airspeed slow, and the angle of attack high, the effect of torque is greater. During takeoffs and climbs, when the effect of torque is most pronounced, the pilot must apply sufficient right rudder pressure to counteract the left-turning tendency and maintain a straight takeoff path.”