On January 30, 1994, at 1820 hours Pacific standard time, a Cessna 182, N21106, overran runway 20 and nosed over during the takeoff roll at Watsonville Airport (WVI), Watsonville, California. The pilot was beginning a night visual flight rules personal flight to San Martin Airport (Q99), San Martin, California. The airplane, registered to and operated by the pilot, sustained substantial damage. Neither the certificated private pilot nor his passenger was injured. Visual meteorological conditions prevailed. The pilot reported in a telephone interview conducted on January 31, 1994, that the airspeed did not register during the takeoff roll and he elected to abort the takeoff. However, the remaining runway was insufficient to stop the airplane on the runway environment. The airplane exited the departure end of the runway. The nose gear collapsed when the airplane entered the soft clay terrain and the airplane nosed over onto its back. The pilot further said that the engine was producing the required takeoff power. His post accident inspection of the airplane revealed that he did not remove the pitot tube cover during the preflight inspection. In addition, the pilot submitted the required Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1/2. He reiterated his telephone statement in the report. He added, however, that he began to abort the takeoff with about 3,800 feet of runway remaining. Mr. James Friel, principal operations inspector, Federal Aviation Administration (FAA), San Jose [California] Flight Standards District Office, conducted the on-scene investigation. Inspector Friel reported that the airplane's tire skid marks began about 1,042 feet before the end of the runway. The pilot also told him that he did not remove the pitot tube cover before departing.