THE AIRCRAFT WAS SUBSTANTIALLY DAMAGED WHEN IT SWERVED OFF THE SIDE OF THE RUNWAY DURING LANDING ROLL ON THE FIRST FLIGHT BY THE NEW OWNER. THE HOMEBUILT AMPHIBIAN HAD BEEN INSPECTED BY A MECHANIC, WHO SIGNED OFF AN ANNUAL INSPECTION FOR THE ENGINE BUT NOTED THAT THE OWNER DID NOT WANT AN ACFT ANNUAL INSPECTION AT THAT TIME. THE ON-SCENE INSPECTION OF THE AIRCRAFT BY THE FAA DISCOVERED NO DISCREPANCIES IN THE TAIL WHEEL, BUT ANOTHER MECHANIC WHO LOOKED AT THE ASSEMBLY ONE AND A HALF MONTHS LATER FOUND EXCESSIVE WEAR, YIELDING POOR STEERING ABILITY. A SUBSEQUENT EXAMINATION BY THE SAFETY BOARD'S ENGINEERING STAFF SUBSTANTIATED THAT FINDING. THE PILOT STATED THAT HE HAD TROUBLE MAINTAINING DIRECTIONAL CONTROL OF THE AIRCRAFT DURING TAKEOFF. THE PILOT'S LOGBOOK DID NOT INDICATE EXPERIENCE IN TAIL WHEEL AIRCRAFT WITHIN THE PRECEDING THIRTEEN YEARS.