On August 25, 2000, about 1500 Pacific daylight time, a Cessna 180H, N91464, sustained substantial damage while landing on runway 07 at Roche Harbor Airport, Roche Harbor, Washington. The commercial pilot, and the one passenger aboard the aircraft were not injured. The pilot was operating the aircraft as a visual flight rules (VFR) personal/pleasure flight under Title 14 CFR 91, when the accident occurred. Visual meteorological conditions prevailed and no flight plan was filed. The flight originated from Portland, Oregon, (PDX) approximately two hours prior to the accident. During a telephone conversation with the NTSB, the pilot stated that shortly after touchdown (wheel landing), the aircraft drifted to the right (south) of runway centerline. The pilot applied brakes and corrective actions, however, the aircraft continued off the runway and down an embankment that parallels the runway. During the accident sequence, the aircraft's main gear separated from the airframe resulting in substantial damage to the fuselage. Shortly after the accident, a Sheriff's Deputy from the San Juan County Sheriff's Office reported that the winds at Roche Harbor were blowing across the runway at a 30-40 degree angle and estimated that the wind speed was 10-15 knots. He also stated that the winds favored runway 24 (report attached). The 1553 METAR observation taken at Friday Harbor, Washington (6 miles southeast of the accident site), reported winds from 230 degrees true at 7 knots. A FAA inspector from the Seattle, Washington, Flight Standards District Office (FSDO), visually inspected the aircraft after the accident and reported that there was no evidence found to indicate a brake failure or malfunction.