RedactedNarrative: While traveling back to Washington County Park boat ramp on South Holston Lake in Washington County, OPERATOR 1 was operating his vessel from the stern when water began coming over the bow of the vessel, causing it to capsize. PASSENGER 2 and PASSNEGER 1 were sitting side by side in the middle of the vessel when this occurred. The approximate GPS location the vessel capsized was 36.601935, -82.003960. I was unable to locate any damage to the motor or vessel that could have contributed to the accident. OPERATOR 1 made comments that a wake from another boat may have had an affect. The most likely cause of the vessel to become capsized was the capacity and weight limit of the vessel was greatly exceeded. The U.S. Coast Guard capacity plate lists 2 persons or 250 LBS as maximum capacities. Three male subjects, weighing approximately 260 lbs, 270 lbs, and 135 lbs, as well as approximately 100 lbs of gear and a small Labrador Retriever were on board. After capsizing, multiple nearby boats assisted in recovering the subjects from the water. OPERATOR 1 estimated they were in the water for approximately 1 to 2 minutes before being rescued, while Mr. PASSNEGER 1 estimated it was 10 minutes. The boats that had assisted in recovering the subjects had already left when I arrived on scene. I was unable to locate them to interview. The three victims were brought to the Washington County Park boat ramp where their wet clothes were removed and dry clothing was provided by local fishermen. Green Springs Fire Department Chief arrived on scene and assisted with calling for an ambulance and placing the subjects in vehicles to warm them up. PASSENGER 2 and OPERATOR 1 refused medical transport but PASSNEGER 1 was transported to Johnston Memorial Hospital in Washington County after complaining of neck and hand injuries. No PFDs were worn by the occupants of the capsized vessel. OPERATOR 1 claimed during a field interview that there were enough PFDs on board for everyone as well as a type IV throwable. I was only able to locate one type III and one type IV PFD among the recovered items brought to land by the various boats who assisted in the recovery.