-- Last Updated: Feb-16-13 9:21 PM EST --
We have a "What PFD's Can and Can't Do" page on our web site
Some other info:
In Essentials of Sea Survival, Golden & Tipton note that "To qualify for "life-jacket" classification in the UK, adult life-jackets must have in excess of 34lbs of buoyancy." Lesser devices are termed "Buoyancy Aids". On our side of the pond, the Coast Guard doesn't list a single device with buoyancy in excess of 34lbs. The closest ones are Type 1 Inflatable (33lbs), Type II Inflatable (33lbs, and a Type V - Special Use Device - Inflatable (22lbs to 34lbs).
The Coast Guard's information on "RECREATIONAL BOATING PFD SELECTION" is here: http://www.uscg.mil/hq/cg5/cg5214/pfdselection.asp,
and the terminology, while it sheds no light on our life jacket vs PFD discussion, is pretty interesting. In the interest of space, I'll stick to Types I, II & III. Incidentally, no mention is made of supporting the wearer in a face-up position.
TYPE I PFDS / OFF-SHORE LIFE JACKETS: Best for all waters, open ocean, rough seas, or remote water, where rescue may be slow coming. Abandon-ship lifejacket for commercial vessels and all vessels carrying passengers for hire:
TYPE II PFDS / NEAR-SHORE BUOYANT VESTS: For general boating activities. Good for calm, inland waters, or where there is a good chance for fast rescue.
TYPE III PFDS / FLOTATION AIDS: For general boating or the specialized activity that is marked on the device such as water skiing, hunting, fishing, canoeing, kayaking and others. Good for calm, inland waters, or where there is a good chance for fast rescue. Designed so that wearing it will complement your boating activities.
So we have Lifejackets, Life Jackets, Off-Shore Life Jackets, Near-Shore Buoyant Vests, and Floatation Aids, which leaves plenty of room for confusion. The Coast Guard seems to be aware of this, because they have the following disclaimer at the bottom of their page:
"The Coast Guard is working with the PFD community to revise the classification and labeling of PFDs. When completed, this information will be updated and hopefully be somewhat easier to understand."
One thing I find particularly interesting is the recommended use for Type IIIs: "Good for calm, inland waters, or where there is a good chance for fast rescue."
There is currently a push to drop "PFD" in favor of "Life Jacket". I've been using PFD since the 1970's and don't know if my brain can handle that transition.
Hope this is helpful, mates.