On June 11, 2000, about 1130 eastern daylight time, a Grumman G-73T, N142PA, operated by Chalks Airlines Inc., had the captain's side control yoke separate while water taxiing at Watson Island, Florida. Visual meteorological conditions prevailed at the time and a VFR flight plan was filed for the 14 CFR Part 121 scheduled international flight. The airplane received minor damage. The two airline transport-rated pilots, and 15 passengers reported no injuries. The flight departed from Bimini, Bahamas, at an unknown time. After landing, the pilot stayed on the step, and water taxied. The pilot had the control yoke up to his chest, and the captain's side control separated from the vertical column. The surface control column assembly, fitting P/N 112703 was sent to the NTSB Materials Laboratory, Washington, D. C., for examination. According to the laboratory report, the assembly was fractured at the intersection of the stem and collar portion, with four separate fracture regions created. According to the NTSB Materials Laboratory factual report, "...visual examination of the fracture surface...showed no evidence of preexisting fracture areas on any of the four fracture regions. All fractures were typical of overstress separations."