Rule 1
Always Wear Your PFD
With few exceptions, cold shock causes people to immediately lose control of their breathing. As a result, many of them suddenly drown – even though they can swim. A PFD greatly reduces the chance of sudden drowning due to cold shock and swimming failure.
Cold water drowning can occur instantly if cold shock causes a person to gasp while their mouth is underwater. That particular phenomenon used to be called "Sudden Disappearance Syndrome", and it's worth emphasizing that you don't suddenly disappear and sink to the bottom if you're wearing a properly secured PFD.
Drowning can also occur during the first several minutes of cold shock due to swimming failure or inhaling water as a result of wave splash. If you aren’t wearing a PFD, you will drown as soon as you can no longer swim or tread water.
It's not enough to simply buy a PFD and wear it. Unless it's properly sized and adjusted, the PFD can rise up around your ears or slip off entirely.
If you gasp underwater, you will immediately drown. If you aren't wearing a PFD you will head straight to the bottom.
Sudden Disappearance
Four examples of USCG approved Type 3 PFDs
Poorly Adjusted PFDs
These are well known for slipping off when you raise your arms and wave for help. Especially with children.
Inflatables
Inflatable PFDs, with their lower profile, are gaining in popularity. They come in two varieties, auto-inflating ones that inflate automatically when they come into contact with water, and manual-inflating ones that are activated by pulling a tab attached to the device. They provide greater buoyancy than standard Type III foam PFDs, and users find them easier and more comfortable to wear.
Cautionary Note:
Inflatables have two downsides, and both involve a failure to inflate:
First, because they're mechanical devices that use a CO2 cartridge to provide the inflation, they have to be set up properly and kept in good working condition.
Second, the manual ones have to be activated by the user - a fact that makes them a bad choice for cold water immersion - particularly if the user isn't wearing thermal protection. The mental disorientation experienced by a cold shock victim can result in failure to inflate the PFD in time to prevent drowning. Read about Dr. Mirman's close call.
Many paddleboarders wear a waist-mounted, manually-inflatable PFD that's positioned behind them. This leaves the pull-tab in the most difficult position to grab when activating the device. This is a very significant hazard that's resulted in numerus fatalities.
Floatation Coats and Coveralls
How They Work
Floatation coats and coveralls are waterproof garments that combine protection from the elements with built-in foam insulation. The coverall design is frequently called an "anti-exposure suit". The foam is buoyant, and they are USCG approved as personal floatation devices (PFDs). Because of these characteristics, they're widely used for commercial activities.
A Poor Choice For Immersion
Manufacturers say that they "delay hypothermia" when the wearer is immersed in cold water. This is a vague and somewhat misleading term because they're actually a poor choice for protection in the event of cold water immersion.
They're not at all watertight, they can rapidly fill with cold water, and they do nothing to prevent cold shock. Furthermore, at least one popular design provides less than half a CLO of insulation when the wearer is actually in the water. Although these garments are certainly better than no insulation, they don't provide the same level of protection as a wetsuit or drysuit that's appropriate for the water temperature. They're also definitely not a substitute for a survival suit. Cold Water Gear
Note: "CLO" is a measure of insulation. A CLO value of 0 is equivalent to a naked person. A CLO value of 1 is equal to the amount of clothing required by a resting human to maintain thermal comfort at a room temperature of 71F (21C). It's worth noting that this CLO system doesn't consider the insulating value of fat.
Bonus Article: What PFDs Can and Can't Do
Technical Specs:
Rule 1 Case Histories with Lessons Learned
