On October 4, 2008, about 1130 eastern daylight time, a Cessna T210M, N11PC, registered to and operated by a private individual, experienced total loss of engine power and was ditched in a marsh near Savannah, Georgia. Visual meteorological conditions prevailed at the time and no flight plan was filed for the 14 Code of Federal Regulations (CFR) Part 91 personal flight from Trenton Mercer Airport (TTN), Trenton, New Jersey, to Malcolm McKinnon Airport (SSI), Brunswick, Georgia. The airplane was substantially damaged and the certificated private pilot was not injured. The flight originated about 0725, from TNN. The pilot stated that she filled the airplane's fuel tanks several days before the accident flight, though at the time the airplane's tire pressure appeared to be low. She did not perceive a slope of the ramp where the airplane was fueled. She added air to the tires and then asked her certified flight instructor (CFI) to check the tanks to make sure they were full and add fuel as necessary because of the low tire pressure issue, and also because she was aware of the airplane's history related to the fuel system. Less than 1.5 gallons of fuel were added when the CFI fueled the airplane. The airplane was secured in a hangar, and then removed for the accident flight. She did not visually check the fuel tanks during her preflight inspection, but reported there was no evidence of fuel leakage on the floor in the hangar. The flight departed with a previously known inoperative right fuel quantity gauge and the fuel selector positioned to the left fuel tank. After one hour into the flight the pilot repositioned the fuel selector to the right tank, and flew 2 hours 20 minutes. She then repositioned the fuel selector to the left tank, and at that time noted the left fuel quantity gauge indicated 10 gallons remaining though she estimated it should have had 24 gallons remaining. The flight continued and about 1100, the engine surged which was corrected by reducing the throttle control. The flight continued and at some point after the engine surged momentarily she positioned the fuel selector to the right tank and flew for a few minutes. She then repositioned the fuel selector to the left tank, and at that time noted the left fuel quantity gauge indicated zero. The flight continued and several minutes later the engine then began to lose power. She notified air traffic control and requested a vector to the nearest airport, which was Hunter Army Airfield. She realized that the flight was unable to land there and maneuvered the airplane for a grassy area. With the flaps and landing gear retracted, she executed a forced landing to a marsh. After coming to rest she exited the airplane, and was rescued by the U.S. Coast Guard approximately 30 minutes later. The pilot did not report any unusual fuel flow issues during the accident flight, which she reported is typically 17.3 to 17.4 gallons per hour during cruise flight. Recovery personnel reported that the airplane was resting in a left wing high attitude. No fuel or water was found in the left fuel tank, while approximately 8 gallons of salt water were drained from the right fuel tank. No fuel was found in the right fuel tank. Examination of the airplane and engine following recovery was performed by an FAA airworthiness inspector. Inspection of the airframe revealed no evidence of fuel leaks from the fuel tank sump drains or fuel caps. Inspection of the engine revealed no fuel in the fuel lines in the engine compartment. Crankshaft, camshaft, and valve train continuity was confirmed. Spark was noted from the left magneto but no spark was noted from the right magneto. A review of the airplane's Pilot's Operating Handbook (POH) pertaining to preflight inspection revealed both tanks are to be visually inspected.