Accident Sequence
While taxiing, the aircraft struck a gravel bar and became stuck. Due to a receding tide the previous night, the aircraft remained trapped on the bar until the following morning. After it was freed, the pilot taxied the aircraft while waiting for daylight to take off. Approximately three hours later, the aircraft rolled over in the water and eventually sank.
Pilot Observations and Float Condition
Before the aircraft disappeared, the pilot noticed two one-inch dents in the submerged float, with bubbles emanating from them. The pilot stated that the floats routinely leaked and required daily pumping, but that this maintenance had not been performed between the time the aircraft struck the gravel bar and when it sank.
Occupant Actions and Outcome
There were no approved personal flotation devices aboard the aircraft. The four occupants used inflated hip waders during an attempt to swim to shore. Two individuals were lost and presumed drowned in this attempt. The water temperature was approximately 45 degrees Fahrenheit.