As early as 870 BC, the army of Assyrian King Ashur Nasirpa II crossed the moat with inflatable animal skins. This shows that the history of life jackets is longer than imagined. Dr. John Wilkinson made the first life jacket out of cork and patented it in 1765. It is reported that cork life jackets entered the market as early as 1804. In 1851, Captain John Rose Ward designed the cork precursor of a modern life jacket for the National Lifeboat Agency.
In the 1860s, cork was still the main component of life jackets, but soon people began to use kapok, a natural fiber. Its wax coating provides the necessary buoyancy to keep air inside the device. It is sealed in a plastic pocket, but there is still a problem, and if punctured, this potentially life-saving instrument may lose buoyancy. Peter Marcus invented the first inflatable life buoy in 1928, providing new developments in this technology. During World War II, these jackets were very popular among U.S. Army Air Forces and Royal Air Force soldiers.
Today, all manufacturers use plastic to make life jackets, and some are made of closed-cell foam or nylon-wrapped foam. Closed-cell foam was invented in the 1940s, but was not used for this function until the 1970s. This closed-cell foam insert consists of tiny, separate air-filled pockets inside the foam, with a sponge-like structure.
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