On May 5, 2001, at 1832 eastern daylight time, N744LS, a Maule M-7-235B floatplane, operated by a private pilot, flipped over and sank while landing on Lake Missaukee, near Lake City, Michigan. The pilot and two passengers received minor injuries. The airplane was substantially damaged. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions without a flight plan. The flight originated from Lake Missaukee, at about 1815 eastern daylight time. The pilot reported that he departed Lake Missaukee en route to Cadillac, Michigan for fuel. He reported that upon lowering the gear in preparation for landing at Cadillac, he was unable to get a gear down indication. He then returned to Lake Missaukee to land. He reported that he cycled the landing gear selector and the circuit breaker four times. The pilot reported that prior to landing he pulled the circuit breakers, moved the selector to the gear up position, pumped the gear switch motor to the up position, pumped the gear hydraulic pump 15 to 20 times with positive pressure and turned the gear selector switch to off. He reported that he thought the gear was in the retracted position prior to landing. The pilot reported that upon landing as he slowed the airplane, the force of the water pulled the landing gear down and the airplane nosed over. Inspection of the airplane after the accident revealed that the hydraulic line to the left gear had separated porting the hydraulic fluid. It was determined that the hydraulic line was not properly flared at the fitting.