There was a time not too long ago when a personal flotation device (PFD) was only that—a device that would float a person. Coast guard–requirements, so the story goes, precluded adding pockets, because PFD wearers, in theory, could fill those pockets with lead, and the device would no longer float itself, let alone a person. The requirements have since changed, and approved PFDs now have a variety of pockets.
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The Chinook has two side cinches in addition to a waist belt. The back has its foam panel placed up high, above a mesh panel that supports the cinch straps and waist belt. The configuration at the back keeps the PFD from hindering layback rolls.
If you subscribe to the theory that our working memory maxes out when dealing with more than seven (plus or minus two) elements, we suggest that you leave at least one pocket empty.