Fly 911 - the Sea King, which is designed to land on the water, is very twitchy especially in roll when afloat - even on a flat calm Canadian lake. The S-92 which isn't designed to land on water would probably be very difficult to keep upright, especially in a 2 metre swell, even with all the flot bags deployed.
Had they made a controlled ditching in those conditions they would probably still have inverted.