The pilot reported that, the airplane touched down on the first 1/3 of the wet grass runway, at 80 mph with 10° of flaps extended. He added, that about 2/3 of the way down the runway the airplane "hit a bump and became airborne again." As the airplane touched down for the second time, he felt as though he was running out of room and applied the brakes. Subsequently, the end of the runway was approaching fast and he attempted to turn the airplane, but continued to slide off the runway, "as the brakes were locked."

The airplane sustained substantial damage to the firewall.

The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.