Snorkeling
Snorkeling is the practice of swimming face-down in a body of water while breathing the ambient air through a shaped tube called a snorkel, usually with swimming goggles or a diving mask, and swimfins. In cooler waters, a wetsuit is also worn. The use of this equipment allows the snorkeler to observe the underwater environment for extended periods with relatively little effort, and to breathe while face-down at the surface.
Snorkeling is a popular recreational activity, particularly at tropical resort locations. It provides the opportunity to observe underwater life in a natural setting without the complicated equipment and training required for scuba diving. It appeals to all ages because of how little effort is involved and is the basis of the two surface disciplines of the underwater sport of finswimming.
Snorkeling is also used by scuba divers when at the surface, in underwater sports such as underwater hockey and underwater rugby, and as part of water-based searches conducted by search and rescue teams.
Equipment
Essential equipment includes the snorkel for breathing, and a diving mask or swimming goggles for vision. Swimfins for more efficient propulsion are common. Environmental protection against cold, sunburn, and marine stings and scratches is also regionally popular, and may be in the form of a wetsuit, dry suit, dive skins, or rash vest. Some snorkelers rely on waterproof sunscreen lotions, but some of these are environmentally damaging. If necessary, the snorkeler may wear a weightbelt to facilitate freediving, or an inflatable snorkeling vest, a form of buoyancy aid, for safety.Snorkel
A snorkel is a device used for breathing air from above the surface when the wearer's head is facing downwards in the water with the mouth and the nose submerged. It may be either separate or integrated into a swimming or diving mask. The integrated version is only suitable for surface snorkeling, while the separate device may also be used for underwater activities such as spearfishing, freediving, finswimming, underwater hockey, underwater rugby and for surface breathing with scuba equipment. A swimmer's snorkel is a tube bent into a shape often resembling the letter "L" or "J", fitted with a mouthpiece at the lower end and constructed of light metal, rubber or plastic. The snorkel may come with a rubber loop or a plastic clip enabling the snorkel to be attached to the outside of the head strap of the diving mask. Although the snorkel may also be secured by tucking the tube between the mask strap and the head, this alternative strategy can lead to physical discomfort, mask leakage or even snorkel loss.Snorkels constitute respiratory dead space. When the user takes in a fresh breath, some of the previously exhaled air which remains in the snorkel is inhaled again, reducing the amount of fresh air in the inhaled volume, and increasing the risk of a buildup of carbon dioxide in the blood, which can result in hypercapnia. The greater the volume of the tube, and the smaller the tidal volume of breathing, the more this problem is exacerbated. A smaller diameter tube reduces the dead volume, but also increases resistance to airflow and so increases the work of breathing. Including the internal volume of the mask in the breathing circuit greatly expands the dead space. Occasional exhalation through the nose while snorkeling with a separate snorkel will slightly reduce the buildup of carbon dioxide, and may help in keeping the mask clear of water, but in cold water, it will increase fogging. To some extent the effect of dead space can be counteracted by breathing more deeply and slowly, as this reduces the dead space ratio and work of breathing.
Snorkels come in two orientations: Front-mounted and side-mounted. The first snorkel to be patented in 1938 was front-mounted, worn with the tube over the front of the face, and secured with a bracket to the diving mask. Front-mounted snorkels proved popular in European snorkeling until the late 1950s when side-mounted snorkels came into the ascendancy. Front-mounted snorkels experienced a comeback a decade later as a piece of competitive swimming equipment to be used in pool workouts and in finswimming races, where they outperform side-mounted snorkels in streamlining.
Plain snorkel
A plain snorkel consists essentially of a tube with a mouthpiece to be inserted between the lips.The barrel is the hollow tube leading from the supply end at the top of the snorkel to the mouthpiece at the bottom. The barrel is made of a relatively rigid material such as plastic, light metal or hard rubber. The bore is the interior chamber of the barrel; bore length, diameter and bends all affect breathing resistance.
The top of the barrel may be open to the elements or fitted with a valve designed to shut off the air supply from the atmosphere when the top is submerged. There may be a high visibility band around the top to alert other water users of the snorkeler's presence. The simplest way of attaching the snorkel to the head is to slip the top of the barrel between the mask strap and the head. This may cause the mask to leak, however, and alternative means of attachment of the barrel to the head include threading the mask strap a molded on the barrel, using a figure-8 rubber snorkel keeper pulled down over the barrel, or a rotatable plastic snorkel keeper clipped to the barrel.
The mouthpiece helps to keep the snorkel in the mouth. It is made of soft and flexible material, originally natural rubber and more recently silicone or PVC. The commonest of the multiple designs available features a slightly concave flange with two lugs to be gripped between the teeth. The tighter the teeth grip the mouthpiece lugs, the smaller the air gap between the teeth and the harder it will be to breathe. A tight grip with the teeth can also cause jaw fatigue and pain.
Full-face snorkel mask
An integrated snorkel consists essentially of a tube topped with a shut-off valve and opening at the bottom into the interior of a diving mask. Integrated snorkels must be fitted with valves to shut off the snorkel's air inlet when submerged. Water will otherwise pour into the opening at the top and flood the interior of the mask. Snorkels are attached to sockets on the top or the sides of the mask.New-generation snorkel masks are full-face masks covering the eyes, the nose, and the mouth. They enable surface snorkelers to breathe nasally or orally and may be a workaround in the case of surface snorkelers who gag in response to the presence of standard snorkel mouthpieces in their mouths. Some early snorkel masks are full-face masks covering the eyes, nose, and mouth, while others exclude the mouth, covering the eyes and the nose only. The 1950s US Divers "Marino" hybrid comprised a single snorkel mask with eye and nose coverage and a separate snorkel for the mouth.
Full-face snorkel masks use an integral snorkel with separate channels for intake and exhaled gases theoretically ensuring the user is always breathing untainted fresh air whatever the respiratory effort. They come with a built-in dry top snorkel system. In addition to a standard ball float system that stops the water from entering the tube when submerged, full-face masks are designed in such a way that even if a small amount of water does get into the snorkel, it will be channeled away from the face and into the chin area of the mask. A special valve located on the bottom of the chin allows to drain the water out. The main problem is that it must fit the whole face well enough to make a reliable seal and since no two faces are the same shape, it may not seal adequately on any specific user. In the event of accidental flooding, the whole mask must be removed to continue breathing. Unless the snorkeler is able to equalize without pinching their nose it can only be used on or within several feet of the surface, since the mask covers the nose with a rigid plastic structure, which makes it impossible to pinch the nose if needed to equalize pressure at greater depth. Trained scuba divers are likely to avoid such devices, however, snorkel masks are a boon for those with medical conditions that preclude taking part in scuba diving.
As a result of a short period with an unusually high number of snorkeling deaths in Hawaii there is some suspicion that the design of the masks can result in buildup of excess CO2. It is far from certain that the masks are at fault, but the state of Hawaii has begun to track the equipment being used in cases of snorkeling fatalities. Besides the possibility that the masks, or at least some brands of the mask, are a cause, other theories include the possibility that the masks make snorkeling accessible to people who have difficulty with traditional snorkeling equipment. That ease of access may result in more snorkelers who lack experience or have underlying medical conditions, possibly exacerbating problems that are unrelated to the type of equipment being used.
During the 2019–20 coronavirus pandemic related shortages, full-face snorkel masks were adapted to create oxygen dispensing emergency respiratory masks by deploying 3D printing and carrying out minimal modifications to the original mask. Italian healthcare legislation required patients to sign a declaration of acceptance of use of an uncertified biomedical device when they were given the modified snorkel mask for respiratory support interventions in the country's hospitals. France's main sportwear and snorkel masks producer Decathlon paused its sale of snorkel masks, redirecting them instead toward medical staff, patients and 3D printer operations.