page_title: Wetsuit
section_title: Semi-dry suits
hierarchical_section_title: Wetsuit / Insulation / Semi-dry suits
caption_attribution_description: en:wetsuit, detail of wet suit zipper arrangement, showing the zipper and the protective cover. The cover further reduces water flow through the closure.
context_page_description: A wetsuit is a garment worn to provide thermal protection while wet. It is usually made of foamed neoprene, and is worn by surfers, divers, windsurfers, canoeists, and others engaged in water sports and other activities in or on water, primarily providing thermal insulation, but also buoyancy and protection from abrasion, ultraviolet exposure and stings from marine organisms. The insulation properties of neoprene foam depend mainly on bubbles of gas enclosed within the material, which reduce its ability to conduct heat. The bubbles also give the wetsuit a low density, providing buoyancy in water.
  Hugh Bradner, a University of California, Berkeley, physicist invented the modern wetsuit in 1952. Wetsuits became available in the mid-1950s and evolved as the relatively fragile foamed neoprene was first backed, and later sandwiched, with thin sheets of tougher material such as nylon or later spandex. Improvements in the way joints in the wetsuit were made by gluing, taping and blindstitching, helped the suit to remain waterproof and reduce flushing, the replacement of water trapped between suit and body by cold water from the outside.
context_section_description: Semi-dry suits are effectively a wetsuit with improved seals at wrist, neck and ankles and also usually featuring a waterproof dry-zip. Together, these features greatly reduce the amount of water moving through the suit as the wearer moves in the water. The wearer gets wet in a semi-dry suit but the water that enters is soon warmed up and is not "flushed" out by colder water entering from the outside environment, so the wearer remains warm. The trapped layer of water does not add significantly to the suit's insulating ability. Any residual water circulation past the seals still causes heat loss, but this loss is minimised due the more effective seals. Though more expensive and more difficult to take on and off than a wetsuit (in most cases, a helper will be needed to close the dry-zip, which is usually located across the shoulders), semi-dry suits are cheap and simple compared to dry suits, and in the case of scuba diving, require no additional skills to use. They are usually made from thick Neoprene (typically 6mm or more), which provides good thermal protection at shallow depth, but lose buoyancy and thermal protection as the gas bubbles in the Neoprene compress at depth, like a normal wetsuit. Early suits marketed as "Semi-dry" suits came come in various configurations including a one-piece full-body suit or two pieces, made of 'long johns' and a separate 'jacket'. Almost all modern semi-dry suits are one piece suits with, with the zipper usually being a dry-zip across the shoulders on the back, but other arrangements have been used. Semi-dry suits do not usually incorporate boots, and modern designs usually do not incorporate the hood (as creating a secure seal around the face is difficult) so a separate pair of wetsuit boots, hood and gloves as worn, as needed. They are most suitable for use where the water temperature is between 10 and 20 °C (50 and 68 °F).
caption: Detail showing zipper attachment, internal flap and cover flap of semi-dry suit
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