During a personal flight with three passengers onboard, the pilot of the Robinson R44 II decided to examine more closely some fish which the occupants spotted from the helicopter while they were about 320 feet above the water. The pilot turned the helicopter to the right 20 degrees and "settled forward into the wind" for hover at approximately 200 feet. The helicopter however, continued to turn to the right and the pilot was unable to arrest the turn. He then "made the call," to set the helicopter down and inflated the floats. Upon touchdown on the surface of the water the helicopter "flipped to the left" and became partially submerged. None of the four occupants were injured. The helicopter received substantial damage to the fuselage and tail boom. Examination of the helicopter by a Federal Aviation Administration inspector did not reveal any preimpact malfunctions. At the time of the accident, the helicopter was close to gross weight, the wind was 080 degrees at 5 knots, and the temperature was 31 degrees Celsius.