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 drown.
Sudden Disappearance
Poorly Adjusted PFDs
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:
However, 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. This is because the mental disorientation that a cold shock victim experiences can lead them to fail to inflate in time to prevent themselves from drowning. Read about Dr. Mirman's close call.
Of particular concern is the fact that many paddleboarders wear a waist-mounted, manually-inflatable style that they position with the device behind them, which leaves the pull-tab in the most difficult position to grab when activating the device. This is a very significant hazard.
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 outdoor activities.
A Poor Choice For Immersion
Manufacturers promote them as garments that "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, rapidly fill with cold water, and do nothing to prevent cold shock. Furthermore, at least one popular design provides less than 0.5 clo of insulation when the wearer is actually in the water. Although they're 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 not a substitute for a survival suit. Cold Water Gear
Bonus Article: What PFDs Can and Can't Do
Technical Specs:
