As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CRUISE FLIGHT AT 800 FEET AGL, 105 KNOTS , AIRCRAFT PICKED UP A MEDIUM TO SEVERE 1-1 VERTICAL VIBRATION. REDUCED AIRSPEED TO 60 KNOTS, INFLATED FLOATS, AND LANDED IN A MARSH AREA. REMOVED AND REPLACED ONE M/R BLADE. DEBONDING JUST AFT OF LEADING EDGE AREA APPROXIMATELY 1 INCH BY 3 INCHES SEPARATED CAUSED BY CORROSION UNDER SKIN. APPEARS TO HAVE STARTED ADJACENT TO TIP CAP AND MOVED SPAR WISE.