Depending on your aircraft and its operation, you may be required to have a life raft(s) with rated capacity and buoyancy for all of your passengers. The FAA now requires a life raft on-board for flights over 50 miles overwater operations for Parts 121, 125 and 135 aircraft and for Part 91.501 over 100 miles overwater. And when traveling internationally, different regulations like the ICAO or Canadian regulations may additionally require one. Even if not mandated, large bodies of water, like lakes are an unforgiving environment, with hypothermia being a constant threat. For all aircraft, including Part 91 General, a life raft is the best protection from the elements when going further than gliding distance from land.