On January 14, 2004, approximately 1030 Pacific standard time, a Cessna 185F airplane, N185WB, was substantially damaged following a loss of control during landing roll at the Deer Park Airport (DEW), Deer Park, Washington. The airplane was registered to and operated by a private individual. Neither the commercial pilot dual student nor the airline transport pilot flight instructor were injured. Visual meteorological conditions prevailed for the 14 CFR Part 91 local instructional flight, and a flight plan was not filed. The flight departed DEW at approximately 1015. According to the Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1/2), the left seat dual student reported he was receiving instruction to refresh his "dormant tailwheel skills," and at the same time building the 10 hour minimum for the time-in-type insurance requirement. The pilot reported he had received 2.1 hours of instruction on November 20, 2003, and 1.6 hours of instruction on the day prior to the accident. On the morning of the accident a normal takeoff was made on runway 16 with the instructor in the right seat. The dual student stated that he made a normal full flap approach to a wheel landing, and after touchdown the power was reduced and the tail began to settle. The pilot further stated that before the tail touched down the airplane began to swerve to the left. The pilot related that corrective action was taken to briefly stabilize the aircraft, however, it now began to swerve to the right which he could not correct with full left rudder. The pilot reported that the aircraft then departed the right side of the runway and impacted an 18 inch snow berm, resulting in the aircraft nosing over and coming to rest in an inverted position. The pilot stated that as far as he could tell the instructor provided no assistance in helping him recover from the loss of control, and that he had told the instructor prior to the flight that he still wasn't comfortable with the airplane. In a statement provided to the NTSB investigator-in-charge (IIC), the right seat instructor pilot stated that following the wheel landing and during the landing rollout, the aircraft began a "slight" swerve. "The pilot was correcting properly and then encountered a secondary swerve. The runway was clear but wet. The pilot was unable to completely correct the secondary swerve in time." The instructor pilot stated that the aircraft then left the runway at a slight angle and subsequently the main wheels plowed through a snow bank at the edge of the runway, started a slow nose over, and came to rest upside down. An FAA inspector, who examined the wreckage, reported the outboard section of the left wing from the upper strut attach point was bent down approximately 20 degrees and had sustained substantial damage. The inspector also reported the vertical stabilizer and rudder were substantially damaged. At 1053, the weather observation facility at DEW reported wind calm, visibility 10 statute miles, broken clouds at 7,000 feet MSL, overcast clouds at 9,000 feet MSL, and an altimeter setting of 30.20 inches of Mercury.