People have utilised a variety of materials to aid their buoyancy in the water; the earliest recorded examples being inflated animal skins and simple pieces of wood. In survival equipment, cork and then kapok (a soft, light, hollow vegetable fibre) were commonly used until they were superseded by synthetic foams in the 1970s. These plastics materials offered improved performance due to their structure (closed cells, essentially small air-filled pockets), their durability, and resistance to mechanical and chemical deterioration.
The Crewsaver Ski-neo vest (1) is intended for use in active surface watersports including dinghy sailing and kayaking; activities that tend to take place in calm, sheltered waters, close to the shore. It contains plasticised polyvinyl chloride (PVC) foam that provides 50N (newtons) of integral buoyancy to assist the wearer in keeping afloat whilst conscious and treading water.
With 100N of buoyancy, the Baltic lifejacket (2) is suitable for babies and young children within the weight range 0-15kg. It is officially classed as a lifejacket because the design will turn an infant into the upright position once in the water, keeping the airways clear. As the front polyethylene foam section floats up, the child’s bodyweight rotates down and back, with the large collar supporting the head. To achieve this level of safety in adults, a combination of both synthetic foam and inflatable chambers is often necessary. A common sight along the UK coastline, lifebuoys (3) are installed as Public Rescue Equipment because they are effective and easy to use. Intended to be thrown to a casualty in the water to help them stay afloat, this example has a buoyancy rating of 180N provided by polyurethane foam. It is brightly coloured and has reflective tape for visibility.
The Spector competition impact vest (4) also contains foam but here it is intended for the purpose of protecting the body when hitting the water at speed. Recommended for adrenaline watersports such as wakeboarding and kitesurfing, the doublelayered polyvinyl chloride (PVC) is structured as armoured panels around the torso to reduce the risk of injury and bruising whilst being lightweight, thin and flexible for comfort and to allow a full range of movement.