On August 21, 2004, about 1000 mountain daylight time, a tail-wheel equipped 2004 Tubbs PA-18-225 DD, N7993A, sustained substantial damage following a runway excursion and subsequent nose-over at the Lemhi County Airport, Salmon, Idaho. The airplane is owned by the pilot and was being operated as a visual flight rules (VFR) personal/pleasure flight under the provisions of Title 14, CFR Part 91, when the accident occurred. The private pilot, the sole occupant of the airplane, was not injured. Visual meteorological conditions prevailed, and no flight plan was filed for the proposed flight. In a written statement the pilot reported that the airplane "veered to the left" shortly after commencing the takeoff roll. The pilot reported that corrective actions were taken, however, he was unable to correct the situation before the airplane exited the runway edge. After exiting the runway, the airplane encountered a drainage ditch and nosed over resulting in substantial damage to the left wing and vertical stabilizer. No preaccident mechanical malfunctions or failures were reported. The pilot reported that the winds were calm at the time of the accident.