Incident Overview
The pilot of a floatplane reported that the aircraft exhibited sluggish performance during the takeoff run and initial climb from a channel, given the weight conditions. After becoming airborne, the aircraft maintained a shallow rate of climb. As the flight approached land, the pilot encountered glassy water conditions and a downdraft.
Sequence of Events
In an effort to remain over water, the pilot initiated a right turn. During this maneuver, the right float made contact with the water surface. The aircraft subsequently cartwheeled and came to rest inverted in the water.
Pilot Statement
The pilot stated that the aircraft's performance was insufficient for the existing weight conditions during the takeoff and initial climb. The combination of glassy water and a downdraft was noted as the flight neared land, prompting the turn that led to the float contacting the water.
Outcome
The aircraft came to rest inverted after the cartwheel. No further details about injuries, damage, or rescue were provided in the source.