Type II PFDs don't turn all people over, as shown when our editor floated in a pool. The life jacket failed to right him.

Personal Flotation Device, or PFD—the thing you used to call a life jacket—is probably the single most important safety aid you can use on your boat. And yet it’s one of the least understood. A PFD can save your life if you fall overboard (if you’re wearing it). Any PFD is much better than none, but there are some significant differences among them. What’s more, the number of different kinds of PFDs has increased drastically over the past few years, and the most widely available source of information (the little USCG booklet called "Think Safe" that is attached to every USCG-approved PFD) is often several years out of date and…