On July 9, 1995, about 1148 eastern daylight time, an Enstrom F- 28A, helicopter, N203Q, collided with water during takeoff from the Riverfront Heliport (P97), Philadelphia, Pennsylvania. The helicopter received minor damage. The pilot and two passengers were not injured. Visual meteorological conditions prevailed, and no flight plan had been filed. The flight was being conducted under 14 CFR Part 91, as a local sightseeing excursion. The pilot maneuvered the helicopter for takeoff to the east, over the Delaware River. He stated that "as the helicopter entered effective translational lift, it began to sink, and the rotor rpm bled down." The pilot increased the throttle, but according to his statement, the "rpm's did not increase in time." The helicopter skids contacted the water resulting in the helicopter contacting the water and sinking. The pilot stated, "I do not believe that there was a mechanical problem...I failed to maintain safe operating rpm on takeoff." According to the FAA Inspector's statement the pilot told him that after the rotor rpm began to decrease, "...he didn't give enough throttle and didn't stay ahead of the rpm." The FAA reported that the winds at the time of the accident were from 270 degrees, at 9 knots. At the time of the accident, the pilot had 770 total flight hours, and 55.9 flight hours in this make and model helicopter. Life vests were available and accessible to all the occupants, but they were not used. The helicopter was not equipped with floats. Additional damage to the helicopter occurred during the recovery operation, when the police department pulled the helicopter from the river across large rocks.