On June 10, 1998, approximately 1800 Pacific daylight time, a Schweizer SGS 2-33A, N65918, registered to Willamette Valley Soaring Club, Inc., and being operated and flown by a private pilot, was substantially damaged when the left wing outboard leading edge impacted a pole during landing roll at the North Plains Gliderport, North Plains, Oregon. The pilot and his passenger were uninjured. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was to have been operated under 14CFR91, was personal, and originated at the airfield approximately 1730. The pilot reported that he "failed to maintain proper control of the aircraft, deviated from an acceptable track down a grass runway (270) and contacted a pole with the left wing" and that the "impact was relatively slow (10-15 mph)." Additionally he reported that the point of contact was about 18 inches inboard from the left wingtip and that he "was in the process of turning out to avoid another object." The pilot also reported that the "conditions at the time were calm, with heavily overcast skies and light precipitation on the field. He "vividly recall(ed) seeing our newly acquired bright white golf cart parked on the runway side of our ops area and subsequent examination of the ground track clearly indicates a deviation to the left of the nominal centerline as I apparently lost my concentration and steered toward the cart which was parked about 3 feet from the pole. My passenger commented that we seemed to be getting close to the cart, and I responded by lifting the left wing to assure clearing the cart and turning right as I did so. My first reaction on feeling the contact with the pole was disbelief, because I knew I could not have struck the cart, and the pole simply hadn't registered in my mind at all." In a telephone conversation with the pilot-in-command, the pole was further described as supporting an antenna and having a bright yellow parachute centered over the pole and opened up to provide coverage of the operations table sheltered beneath it. The parachute had been taken down and thus the conspicuity of the pole was no longer enhanced by the familiar bright yellow parachute which the pilot-in-command was accustomed to seeing on rollout. The pole itself had no high conspicuity markings. The rear seat passenger, who had no visual expectations during the landing roll did see the bright white golf cart but also missed seeing the pole. The pilot-in-command, concentrating on the golf cart and never seeing the pole, failed to see or at least realize the consequences of the pole's proximity, and thus executed no avoidance action. Additionally, the pilot-in-command reported that the runway was not marked laterally (sidelines), the runway ends (thresholds) were unmarked, nor was there any centerline markings for directional guidance. Also, the gliderport, which is owned by the same organization which owns the accident aircraft, may have been unaware of the standards set forth in Federal Air Regulation Part 77, which deals with objects penetrating both the 20:1 approach clearance planes at the runway ends as well as the 7:1 transitional planes along the runway sides. Winds at the Hillsboro airport located 5 miles east-southeast of the site were calm at the time and the pilot-in-command reported calm winds at the time of the accident. He also reported rain at the time of the accident and a "uniformly gray" background to the west.