On May 19, 2003, about 1220 eastern daylight time, a Cessna 175A, N6989E, was substantially damaged while ditching in the Atlantic Ocean, following a loss of engine power after takeoff from Ocean City Municipal Airport (26N), Ocean City, New Jersey. The certificated commercial pilot was not injured. Visual meteorological conditions prevailed for the planned flight to Cape May County Airport (WWD), Wildwood, New Jersey. No flight plan was filed for the personal flight conducted under 14 CFR Part 91. The pilot reported that during the initial climb, about 800 feet msl, the engine experienced a partial loss of power. The pilot made a 180-degree turn back toward the airport, but was unable to maintain altitude. He ditched the airplane in shallow water near the coast, about 2 miles south of the airport. The pilot further stated that it was possible that the airplane's single fuel vent was obstructed, which resulted in the power loss. Examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed damage to the left wing and fuselage. He also observed fuel in both fuel tanks. The inspector stated that he examined fuel vent and did not find any blockage. The FAA inspector, with assistance of an aircraft recovery company, drained water from the carburetor. He also drained and replaced the engine oil; removed, cleaned, and reinstalled all spark plugs; and rotated the crankshaft. The inspector attained thumb compression on all cylinders and confirmed crankshaft, camshaft, and valve train continuity. However, the engine would not start. Subsequently, the carburetor was inspected and no discrepancies were noted. Both magnetos were inspected, and the left magneto was subsequently cleaned. On the second attempted, the engine "fired," but did not run. The inspector could not determine why the engine experienced a partial loss of power.