DON CASEY REPLIES
How reliable are auto-inflate life vests? Very. However, the only quantitative assessment we can state with certainty is that they are not 100 percent reliable. Safety experts report occasional (maybe rare is a better word) failures during PFD demonstrations. However, even a single failure can spell disaster, as this fatality you cite tragically illustrates. You have reason to be concerned.
We do not know even the brand of vest that failed Jon Santarelli (the sailor who died shortly after the start of the Mac Race), but that may actually be a blessing. It avoids the unwarranted confidence that you or I might have in a different brand. In fact, nearly all automatic inflatable PFDs use similar or identical inflating mechanisms.
Anyone depending on an inflatable vest, automatic or not, to provide adequate buoyancy in an emergency should give more attention to that vest than I suspect most receive. That means a thorough examination every time before donning, which includes, but is not limited to, checking the service indicator to be sure it is green. Not less often than once a season you should also unpack the vest and inflate the bladder, giving it time to demonstrate that it is leak-free before you deflate and repack. Along these same lines, disarming and rearming the inflator seasonally and inspecting the bobbin if your vest uses one are also good ideas. The bobbin should have a ribbed surface: if smooth, replace it. All vest manufacturers have YouTube videos online that will instruct you on correctly arming and packing.
Beyond that, the best way to confirm the reliability of a vest is to put it on and jump into the water. The result should be both instructional and reassuring. Rearm kits are not cheap, but not expensive either in light of what you expect from them. If you have seen your vest function perfectly and then you personally rearm and repack it, that will go a long way toward providing the assurance you are seeking, and justifiably so. (Kind of like packing your own parachute.) Manufacturers typically recommend rearming every third year, but adopting a shorter calendar that includes an activation test can only improve peace of mind.
Inflatable PFDs are popular because they are comfortable enough to wear at all times. That means they provide far greater real protection
than a bulky, inherently-buoyant vest stowed in a locker. Taking active measures to reassure yourself about your own vest should allay your concerns.