Snorkel. A snorkel (also spelled "schnorkel" or "schnorchel") is a tube that allows a person, vehicle, or vessel to draw air while submerged under water. A swimmer's snorkel is a tube about thirty centimetres (twelve inches) long, usually J-shaped, fitted with a reasonably comfortable mouthpiece, and constructed of rubber or plastic. It is used for breathing air from above the water surface when the mouth and nose are submerged, either during a surface swim before or after scuba diving, or during snorkeling. The most common type of snorkel is a simple tube that is allowed to flood when underwater. The snorkeller expels water from the snorkel with a sharp exhalation on return to the surface. Some modern snorkels have a sump in the mouthpiece to allow a small volume of water to remain in the snorkel without being inhaled when the diver breathes. Some have a one-way output valve in the sump, which automatically drains the sump as it fills with water. Some snorkels have float-operated valves attached to the surface end of the tube to keep water out when the snorkeller submerges. The maximum length of the tube is around fifty centimetres (twenty inches). A longer tube would place the lungs in deeper water where the surrounding water pressure is higher and the lungs would be unable to inflate when the diver inhales, because the muscles that expand the lungs are not strong enough to operate against the higher pressure. PADI 5 Star National Geographic Instructor Development Center. 49 Thaweewong Road, Patong Beach, Phuket, Thailand. Phone: (+66) 076292052 Fax: (+66) 076293034
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