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Personal flotation device

technology Maturity 11-13 Next article →

A personal flotation device, or PFD, is a specialized piece of equipment designed to prevent drowning.

LifevestlocationSeatbeltreminder
LifevestlocationSeatbeltreminder

These devices are known by many names, including life jackets, life vests, and buoyancy aids. Their primary function is to keep a wearer afloat in a body of water. A successful PFD keeps the user's head and mouth above the surface. This allows a person to stay afloat without needing to swim or tread water. Most importantly, a PFD can keep a person afloat even if they are unconscious.

Childs life vest
Childs life vest

Most PFDs function through the principle of buoyancy. Many are constructed from foam pieces that naturally float in water. Others use air chambers, also called bladders, to provide lift. On airplanes, these bladders are often inflated using a canister of carbon dioxide gas. A person can also inflate these cells orally by blowing into a flexible tube. This tube includes a one-way valve to seal the air inside the bladder.

Alaska 2007 075
Alaska 2007 075

Some specialized designs use a combination of both foam and air chambers.

There are three main categories of PFDs: life jackets, buoyancy aids, and survival suits. Buoyancy aids are often made with a foam core to allow for freedom of movement. They are common in sports like rafting because they are inexpensive and require little maintenance.

These often include adjustable understraps to prevent the vest from riding up. They may also feature a headrest flap and a grab handle for rescuers. Life jackets and survival suits provide different levels of protection depending on the environment.

Survival suit mg 6520
Survival suit mg 6520

Humanity's attempt to stay afloat has evolved significantly over centuries. Early people used inflated animal skins or hollow gourds to cross deep rivers. In 1802, Abraham Bosquet proposed using canvas bags filled with cork shavings.

PSM V31 D669 Cork jacket and life buoy
PSM V31 D669 Cork jacket and life buoy

By 1854, Captain John Ross Ward created a cork vest for lifeboat crews. This design provided both buoyancy and protection from harsh weather. In 1900, Gustave Trouvé patented a battery-powered lifejacket. This advanced version could power a light to transmit SOS messages and launch flares.

Material science has changed how PFDs are built. In 1904, hard cork was replaced by pouches filled with kapok. Kapok is a soft, vegetable material that made life jackets more flexible.

During World War II, many sailors wore these kapok suits. In 1972, synthetic Beaufort foam became the standard for inherently buoyant jackets. Unlike inflatable models, these foam jackets do not rely on air to function. They are highly reliable and can even support both a rescuer and a rescued person at once.

Some PFDs are famous for their unique histories and names. In 1928, Peter Markus invented an inflatable life preserver.

Mae West life preserver
Mae West life preserver

During World War II, airmen nicknamed these "Mae Wests" after a famous actress. This name came from how the inflated vest changed the wearer's appearance. These devices were vital for pilots, such as Eric Brown, who survived a carrier sinking.

The Fleet Air Arm during the Second World War TR1121
The Fleet Air Arm during the Second World War TR1121

Other specialized gear includes the UVic Thermo Float, which uses neoprene rubber to protect against hypothermia.

Design and regulation ensure that PFDs meet specific safety needs. Civilian devices for recreational boaters differ from military models. Military PFDs may include ballistic nylon to protect air canisters from gunfire. They must also be compatible with other gear like parachute or rappelling harnesses.

Childs life vest
Childs life vest

For visibility, many PFDs are bright orange or yellow. They often feature retroreflective "SOLAS" tape. This tape helps searchlights spot a person in the dark. In the United States, federal laws require children under age 13 to wear a PFD in watercraft.

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🖼️ Images & Media (12)
File:PSM V31 D669 Cork jacket and life buoy.jpg
PSM V31 D669 Cork jacket and life buoy.jpg
File:Men donning kapok suits on ship delivering oil to Allies during WWII (23558647890).jpg
Men donning kapok suits on ship...
File:The Fleet Air Arm during the Second World War TR1121.jpg
The Fleet Air Arm during the Second World...
File:Mae West life preserver.jpg
Mae West life preserver.jpg
File:LifevestlocationSeatbeltreminder.jpg
LifevestlocationSeatbeltreminder.jpg
File:AREA 47 Rafting Imster Schlucht, 2018 (cropped).jpg
AREA 47 Rafting Imster Schlucht, 2018...
File:Lifejacket2.PNG
Lifejacket2.PNG
File:Childs life vest.jpg
Childs life vest.jpg
File:Life vest.jpg
Life vest.jpg
File:Alaska 2007 075.jpg
Alaska 2007 075.jpg
File:Survival suit mg 6520.jpg
Survival suit mg 6520.jpg
File:French bulldog in life jacket.jpg
French bulldog in life jacket.jpg
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