Editing Snorkeling (section)

==Equipment==
Essential equipment includes the [[Snorkel (swimming)|snorkel]] for breathing, and a [[diving mask]] or [[swimming goggles]] for vision. [[Swimfin]]s 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 ===
{{main|Snorkel (swimming)}}
[[File:Vieques underwater a.jpg|thumb|Man wearing adult's 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 sports|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 (scuba)|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.<ref name="Blount and Taylor 1984" />

Snorkels constitute respiratory [[Deadspace (in breathing apparatus)|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]].

[[File:Snorkel shapes.jpg|thumb|Basic snorkel shapes]]
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.
[[File:Snorkel attachment methods.jpg|thumb|Snorkel attachment methods]]
[[File:Snorkel mouthpieces.jpg|thumb|Snorkel mouthpieces]]
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<ref>{{Cite web|title=МАСКИ (ПОЛУМАСКИ, ОЧКИ), ДЫХАТЕЛЬНЫЕ ТРУБКИ, ЛАСТЫ|url=http://ilovediving.ru/articles/maski-polumaski-ochki-dykhatelnye-trubki-lasty|language=ru}}</ref> 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====
[[File:Decathlon Easybreath snorkel mask.jpg|thumb|Decathlon Easybreath 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 [[Pharyngeal reflex|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.<ref>{{Cite web|title=Skin Diving History – US Divers No.43 – Mfg & Retailers|url=http://www.skindivinghistory.com/mfg_retailers/u/US_Divers/43.html|access-date=2021-03-15|website=skindivinghistory.com}}</ref>

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.{{Clarify|reason=can these masks not be cleared in place?|date=September 2019}} 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,<ref>{{cite web|url=https://dipndive.com/blogs/snorkeling/full-face-snorkeling-masks-pros-and-cons|title=Full-Face Snorkeling Masks: Pros And Cons|access-date=July 18, 2022}}</ref> however, snorkel masks are a boon for those with medical conditions that preclude taking part in scuba diving.<ref>{{Cite journal|last=Newton|first=Herbert B.|date=2001-06-01|title=Medical Problems of Recreational Scuba Diving|url=https://www.aafp.org/afp/2001/0601/p2225.html|journal=American Family Physician|volume=63|issue=11|pages=2225|issn=0002-838X}}</ref>{{clarify|reason=how, specifically, are snorkel masks a "boon" for these people?|date=February 2019}}

As a result of a short period with an unusually high number of snorkeling deaths in Hawaii<ref>{{Cite web|date=2020-09-28|title=Full Face Snorkel Mask Dangers [UPDATED 2019]: What's all the Hub Bub, Bub? – Let's Go To Maui|url=https://www.letsgotomaui.net/da-kine/full-face-snorkel-mask-dangers/|access-date=2021-03-15|archive-url=https://web.archive.org/web/20200928105401/https://www.letsgotomaui.net/da-kine/full-face-snorkel-mask-dangers/|archive-date=2020-09-28}}</ref> there is some suspicion that the design of the masks can result in buildup of excess CO<sub>2</sub>. 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.<ref>{{Cite web|date=March 14, 2018|title=Increasingly popular full-face snorkel masks raise safety concerns|url=https://www.cbsnews.com/news/hawaii-full-face-snorkel-mask-related-deaths/|access-date=2021-03-15|website=cbsnews.com|language=en}}</ref>

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.<ref>{{cite web|last=Opoczynski|first=David|title=Coronavirus : quand les inventeurs viennent à la rescousse des hôpitaux|url=http://www.leparisien.fr/societe/coronavirus-quand-les-inventeurs-viennent-a-la-rescousse-des-hopitaux-23-03-2020-8286186.php|date=2020-03-23|website=[[Le Parisien]]|language=French|access-date=2022-07-18}}</ref><ref>{{YouTube|id=w4Csqdxkrfw|title=Charlotte valve}}</ref><ref>{{cite web|title=Easy COVID|url=https://www.isinnova.it/easy-covid19-eng/|website=Isinnova|date=29 January 2021 |language=Italian|access-date=2022-07-18}}</ref> 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 (retailer)|Decathlon]] paused its sale of snorkel masks, redirecting them instead toward medical staff, patients and 3D printer operations.<ref>{{YouTube|id=uZ5Vtf69cAA|title=Pourquoi ne pas distribuer des masques de plongée Décathlon? BFMTV répond à vos questions}}</ref>

===Diving mask===
{{main|Diving mask}}
[[File:Snorkeling gear.jpg|thumb|right|Typical snorkeling equipment: snorkel, diving mask and swimfins]]
Snorkelers normally wear the same kind of mask as those worn by scuba divers. By creating an airspace, the mask enables the snorkeler to see clearly underwater. All scuba diving masks consist of the lenses also known as a faceplate, a soft rubber skirt, which encloses the nose and seals against the face, and a head strap to hold it in place. There are different styles and shapes. These range from oval shaped models to lower internal volume masks and may be made from different materials; common choices are silicone and rubber. A snorkeler who remains at the surface can use swimmer's goggles which do not enclose the nose.

===Swimfins===
{{Main|Swimfin}}
Swimfins, fins or flippers are [[fin]]like accessories worn on the feet,<ref name="AlainPerrier" /> and usually made from [[rubber]] or [[plastic]], to aid movement through the water in [[Water sport (recreation)|water sports]] activities. Swimfins help the wearer to move through [[water]] more efficiently, as [[Foot|human feet]] are too small and inappropriately shaped to provide much [[thrust]], especially when the wearer is carrying equipment that increases [[Fluid dynamics|hydrodynamic]] [[Drag (physics)|drag]].<ref name="pendergast2003" /><ref name="pmid15796314" /><ref name="pmid9148086" /> Very long fins and [[monofin]]s used by freedivers as a means of underwater propulsion do not require high-[[frequency]] leg movement. This improves efficiency and helps to minimize oxygen consumption. Short, stiff-bladed fins are effective for short bursts of acceleration and maneuvering. Open-backed fins allow the wearer to wear them over the top of wetsuit socks or boots which can be useful in cooler water.

===Exposure protection===
{{see also|Wetsuit|Dry suit|Dive skins|Rash guard}}
A [[wetsuit]] is a garment, usually made of foamed neoprene with a knit fabric facing, which is worn by people 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 depend 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. The thickness, fit and coverage of the suit are important factors for insulation. Wetsuit protection can be extended to cover the head, feet and hands with the addition of a hood, gloves, socks or boots.

Back in the 1950s and early 1960s, snorkeling was often undertaken wearing a one-piece or two-piece thin-rubber valveless [[dry suit]].<ref>"For Warmer Clamming, Abalone Picking", ''The Santa Cruz Sentinel'', 23 February 1961, p.8.</ref> In the new millennium, the use of drysuits in snorkelling is seeing something of a resurgence, thanks to the growing popularity of "wilderness swimming" or "wildswimming" in seas, lakes and rivers.<ref>"University of Montana fisheries students check out trout", ''Billings Gazette'', 14 October 2021, p. A10.</ref><ref>"Explore these emerald pools via 'wilderness snorkeling'", ''Statesman Journal'', 28 August 2019, p. 2T.</ref>

[[Diving suit#Dive skins|Dive skins]] are used when diving in water temperatures above {{convert|25|°C|°F|abbr=on}}. They are usually one piece full length garments made from [[spandex|spandex or Lycra]] and provide little thermal protection, but do protect the skin from [[jellyfish]] stings, abrasion and [[sunburn]]. This kind of suit is also known as a 'Stinger Suit'. Some divers wear a dive skin under a wetsuit, which allows easier donning and (for those who experience skin problems from neoprene) provides additional comfort.<ref name="EcoStinger 2014" />

A [[rash guard]], also known as rash vest or rashie, is an athletic shirt made of spandex and nylon or polyester. The name rash guard reflects the fact that the shirt protects the wearer against rashes caused by abrasion, or by sunburn from extended exposure to the sun. These shirts can be worn by themselves, or under a wetsuit. A rash guard by itself is used for light coverage in warm to extreme summer temperatures for several watersports including snorkeling. There are also lower body rash guards, which are similar to compression shorts to be worn under the surfers' boardshorts.

===Weight belt===
{{See also|Diving weighting system#Weight belt}}
[[File:Zavorra.JPG|thumb|Typical weight belt ]]
Weight belts are the most common weighting system currently in use for snorkeling.<ref>{{cite web|title=Scuba diving air Regulators, buoyancy compensators scuba diving equipment, information advice help with scuba gear products safety|url=http://ygraine.membrane.com/enterhtml/live/scuba/products.html|website=Philadelphia Area Dive Shops|access-date=2022-07-18|url-status=dead|archive-url=https://web.archive.org/web/20070621090205/http://ygraine.membrane.com/enterhtml/live/scuba/products.html|archive-date=2007-06-21}}</ref> They are generally made of tough [[nylon]] webbing, but other materials such as [[rubber]] can be used. Weight belts for snorkeling are generally fitted with a quick release buckle to allow the dumping of weight rapidly in an emergency.

The most common design of weight used with a belt is rectangular [[lead]] blocks with two slots in them threaded onto the belt. These blocks can be coated in [[plastic]], which increases corrosion resistance. The plastic coated weights may be marketed as being less abrasive to [[wetsuits]]. The weights may be constrained from sliding along the webbing by metal or plastic [[Glossary of underwater diving terminology#belt slide|belt sliders]]. Another popular style has a single slot through which the belt can be threaded. These are sometimes locked in position by squeezing the weight to grip the webbing, but this makes them difficult to remove when less weight is needed. There are also weight designs which may be added to the belt by clipping on when needed. The amount of weight needed depends mainly on the buoyancy of the wet suit.

===Snorkeling vest===
<!-- target for redirect [[Snorkeling vest]] -->
An inflatable [[Personal flotation device|personal buoyancy aid]] designed for surface swimming applications. In shape, often like a horse-collar [[Buoyancy compensator (diving)|buoyancy compensator]], or [[airline]] [[life jacket]], but only with oral inflation or a CO<sub>2</sub> cartridge for emergencies.