Pilot's Account
The pilot reported that he was conducting practice takeoffs and full-stop landings with the airplane owner in the right seat to achieve tailwheel airplane currency. The airplane insurance company required pilots to be checked out by the airplane owner before being named on the policy; the airplane owner was not a flight instructor.
Accident Sequence
On the second landing, the airplane touched down on the runway centerline on all three wheels simultaneously. As it slowed, it began to veer to the left. The pilot applied right rudder, and the airplane then veered to the right "more assertively" than intended. To avoid striking a runway light while attempting to stay on the runway, the pilot elected to enter what appeared to be an open grass area adjacent to the runway pavement. However, about 25 feet into the grass, the airplane encountered a "marshy area" with standing water and soft mud, causing it to nose over.
Damage and Observations
The airplane sustained substantial damage to the vertical stabilizer and fuselage. The pilot stated that there were no failures or malfunctions associated with the airplane before the accident. He noted that he had received a tailwheel airplane endorsement about three years before the accident, with limited tailwheel time accumulated since then. Additionally, the airplane owner suggested after the pilot's initial landing during the accident flight that he be more "assertive with the rudders."