Life jackets are a common piece of safety equipment for anyone who goes out on the water, such as sailors, fishermen, rafters, and kayakers. Though they come in a variety of formats, they all work on the same principle of being buoyant enough to keep a person afloat indefinitely.
The science of buoyancy says that if the overall density of an object is less than that of the liquid it is submerged in, then it will float to the surface.
Life Jacket Design
Life jackets must be buoyant enough that they will still easily float after the weight of a person is attached to them. They must also be absolutely waterproof, because becoming waterlogged over time would render a life jacket useless.
One type of life jacket uses a compressed air capsule (usually carbon dioxide) to fill a bladder and create buoyancy. These have the virtue of being easily stored (they occupy little space until inflated), but they are not very durable.
Other life jackets use a core of plastic foam, which is honeycombed with micro-bubbles of air just as wood is. These are durable, buoyant and not prone to becoming water logged.
Many life jackets are not considered to really be personal floatation devices by the standards of the U.S. Coast Guard. While they offer buoyancy, they do not offer enough to meet emergency standards and are considered more of a swimming aid by regulatory authorities.
Article Written By Edwin Thomas
Edwin Thomas has been writing since 1997. His work has appeared in various online publications, including The Black Table, Proboxing-Fans and others. A travel blogger, editor and writer, Thomas has traveled from Argentina to Vietnam in pursuit of stories. He holds a Master of Arts in international affairs from American University.