Just for perspective a North Sea helicopter pilot wears a goretex survival suit, fully zipped up and air expelled (we are discouraged from using the zip up the front style) with varying degrees of under garments. Wooly bear suits are the norm at this time of year. Over that we wear a RFD Beaufort Mk44 lifejacket with spray hood, day-night flare and PLB. One employer supplies spare air as well to aid escape. We fly aircraft fitted with emergency floats and ELTs and most modern aircraft are fitted with external life rafts. Now of course that is over kill for a quick trip over the narrow bit of the Channel on a nice day and you will have to decide on what level of investment is appropriate for the flying you do. But it shows what level of thought and experience that has gone into making a ditching as survivable as possible.