Snorkels: Pros & Cons

The snorkel has been considered a standard piece of diving equipment for decades. It provides the simple but useful ability to swim face down on the surface without having to lift your head to breathe. Snorkels can also conserve compressed gas for the dive and help minimize accidental water intake in rough waters when breathing through the regulator is not an option. 
The impact of snorkels is not all positive though. They are a source of drag in the water, which is not a good thing when they tug on the mask, a decidedly critical piece of equipment. They can also be a source of entanglement, for example, with kelp or hair. And they can be incompatible with some equipment configurations. So, what to do?
 
Pro position: A snorkel provides an option that can be helpful in normal situations. This is a straightforward argument. When a snorkel is needed it is likely to be needed quickly, so having it readily available is a valid choice for preparedness.
 
Con position: The need for a snorkel is low when carrying ample gas supplies or on sites where surface swimming is unlikely, where entanglement is likely (wrecks or caves), or where they offer little utility (ice or caves). The irritation of it getting in the way when hanging from the mask also makes it less desirable.
Where to Put It?

Since the hose for most open-circuit regulators comes over the right shoulder, a snorkel is usually least intrusive if mounted on the left side of the mask. Closed-circuit equipment has large hoses on both sides of the head, so keeping the snorkel in a pocket or pouch is likely the best option.

Design Features

A wide variety of snorkel designs have been marketed, ranging from simple J-shaped tubes to complex shapes for streamlining, reducing water entry and facilitating clearing.

A long, straight J-tube snorkel is probably not desirable because of the increased risk of entanglement; snorkels with a curved upper tube typically provide a lower profile.

The bore (internal diameter) and length of snorkels is important. A large bore offers less resistance, but bringing fresh air to the alveoli, where gas exchange occurs, requires inspiring a volume larger than that of the upper airway and the snorkel combined (the functional dead space). The dead-space gas will have an elevated fraction of carbon dioxide, which will stimulate hyperventilation. This is not a problem if the volume of air breathed is sufficient to bring in the required fresh air. However, carbon dioxide will accumulate if the inspired volume is too small, generally forcing the user to stop breathing from the snorkel fairly quickly.

A long skinny tube (think garden hose) is unworkable as a snorkel because of its volume and the difference in pressure on the surface and in the compressed lungs. Drawing air a long way down from the surface is simply not practical. A simple rule of thumb is that the bore of a snorkel should easily exceed the width of your thumb (a little more for those with small hands), and a snorkel should not be much longer than those typically sold by reputable manufacturers.

An early effort to keep water from entering a snorkel (to avoid having to clear it) was to put a 180-degree turn at the top, covered with a basket holding a ping pong ball, which, in theory, would block water from entering the snorkel. The idea was creative but the effectiveness poor and the likelihood of failure high.

The modern approach to making it easier to clear a snorkel involves a one-way valve positioned so that the diver does not have to work as hard as would be required to blow the water from the top of the snorkel. These valves can help, but technique can make them unnecessary. For example, if an ascending diver tilts back his or her head and exhales a modest amount in the final stage of surfacing, flipping his or her head forward upon surfacing will leave most snorkels clear.

Corrugations on the outside of a snorkel are fine if they let the mouthpiece fall out of the way of the regulator mouthpiece (a rotating mouthpiece can be similarly useful), but the internal bore of a snorkel should be smooth to reduce the effort of moving gas through it and to reduce the trapping of water that could be inhaled with a strong inspiration.

Foldable snorkels may be effective for pocket storage, making them acceptable to divers unwilling to carry a snorkel otherwise. The key is to make sure they perform well upon deployment.

High-visibility colors offer a safety benefit for all diving equipment. A high-visibility snorkel is not as effective as a fluorescent hood or suit, but it is still a good idea.

Snorkels and Freediving

Freediving is usually separated from snorkeling by intent; snorkeling is more casual and freediving more extreme. Competitive freedivers would not use snorkels because of the added drag and additional dead space. Other freedivers might use them, however, and this raises the question of whether water would more easily enter the mouth during blackout.

While there are lots of opinions, there are few facts to support either position. It does seem that there is a period immediately after blackout when sufficient muscle tone is preserved to prevent water entry through a normally closed mouth. Getting the victim to the surface immediately and then keeping the airway clear of the water is often sufficient for rapid recovery. An open mouth holding a snorkel filled with water could lead to faster water entry, but this is a difficult question to test ethically. It might be prudent for freedivers to avoid snorkels, but this position is offered with little empirical evidence. More important is to avoid excessive hyperventilation (exchanging more than two or three lungsful of air beyond metabolic need), which can dramatically increase the likelihood of blackout.

Snorkel Choice

Ultimately, the choices of whether to carry a snorkel and which snorkel to carry are up to the individual. It is convenient to not have one get in the way unnecessarily, but it is also great to have it when the need arises. Options for managing gas supply and emergencies are important, and it is nice to have a snorkel on the day the dolphins choose to swim with you after a dive. I favor having a snorkel, typically a more compact version that is easy to wear or carry as the situation demands.

Snorkel Trivia

Many people know that the term "skin" diving refers to snorkel gear, but few know its origins. When military personnel were required to bring mask, snorkel and fins to water sessions, the acronym SKIN was posted on the roster to stand for "swim kit is needed."

No Comments


Categories

 2020
 2019
 2018
 2016
immersion and bubble formation Accidents Acid reflux Acute ailments After anaesthesia Air Quality Air exchange centre Air hose failure Airway control Alert Diver Magazine Alternative gas mix Altitude changes Altitude sickness Aluminium Oxide Ama divers Amino acids Anaerobic Metabolism Annual renewal Apnea Apnoea Archaeology Arterial gas embolism Arthroscopic surgery Aspirin Aurel hygiene BCD BHP BLS Back adjustment Back pain Back treatment Backextensors Badages Bag valve mask Bahamas Balancing Bandaids Barbell back squat Barometric pressure Barotrauma Basic Life Support Batteries Bench press Benign prostate hyperplasia Black Blood flow Blurred vision Boat safety Bone fractures Bouyancy compensators Boyle's Law Boyle\'s Law Bradycardia Brain Breast Cancer Breath Hold Diving Breath hold Breath-hold Breathing Gas Breathing Breathold diving Broken bones Bruising Bubbleformation Buddy Exercise Buoyancy Burnshield CGASA CMAS CO2 COVID-19 COVID CPR Cabin pressure Caissons diseas Camera settings Cancer Remission Cancer treatments Cancer Cannabis and diving Cannabis Cape Town Dive Festival Cape Town Carbon dioxide Cardio health Cardiological Cardiomyopathy Chamber Safety Chamber science Charging batteries Charles' Law Charles\' Law Charles\\\' Law Charles\\\\\\\' Law Charles\\\\\\\\\\\\\\\' Law Chemotherapy Chest compressions Chiropractic Citizen Conservation Cleaning products Coastalexcursion Cold Water Cold care ColdWater Cold Commercial diving Commercial schools Compressed gas Conservation Contaminants Contaminated air Coral Conservation Coral Reefs Corals Core strength Corona virus Courtactions Crohns disease Crowns Crystal build up Crystallizing hoses Cutaneous decompression DAN Courses DAN Profile DAN Researchers DAN medics DAN members DAN report DCI DCS Decompressions sickness DCS theories DCS DEMP DM training DNA DReams Dalton's Law Dalton\'s Law Dalton\\\'s Law Dalton\\\\\\\'s Law Dalton\\\\\\\\\\\\\\\'s Law Dauin island Deco dives Decompression Illness Decompression Sickness Decompression Stress Decompression illsnes Decompression treatment Decompression Deep diving Deep water exploration Delayed Offgassing Dental Diaphragms Diseases Dive Chamber Dive Computer Dive Destinations Dive H Dive Industry Dive Instruction Dive Instructor Dive Pros Dive Research Dive Training Dive Travel Dive accidents Dive buddies Dive computers Dive excursions Dive fitness Dive gear Dive heallth Dive health Dive medicines Dive medicine Dive operators Dive planning Dive safety Dive safe Dive staff Diveleader training Diveleaders Diver Health Diver Profile Diver infliencers Diver on surface Divers Alert Diving Kids Diving Trauma Diving career Diving emergencies Diving emergency management Diving fit Diving guidelines Diving injuries Diving suspended Diving Dizziness Dolphins Domestic Donation Dowels Dr Rob Schneider Drysuit diving Drysuit valves Drysuits Dyperbaric medicines EAPs EAP Ear pressure Ear wax Ears injuries Education Electronic Emergency action planning Emergency decompression Emergency plans Emergency underwater Oxygen Recompression Emergency Enviromental Protection Environmental factors Environmental impact Environmental managment Equalisation Equipment care Evacuations Evacuation Evaluations Even Breath Exercise Exhaustion Extended divetime Extinguisher Extreme treatments Eye injuries FAQ Failures Fatigue Faulty equipment Fillings Fire Coral Fire Safety Firefighting First Aid Equipment First Aid Kit First Aid Training First Aid kits Fish Identification Fish Fitness Training Fitness to dive Fitness Flying Fractures Francois Burman Fredive Free Student cover Free diving Free flow Freedive Training Freediver Freediving performance Freediving Gas Density Gas laws Gas mixes GasPerformance Gases Gastoeusophagus Gastric bypass Gastroenterologist Gear Servicing Gordon Hiles Gutt irritations HCV HELP HIRA HMS Britanica Haemorhoid treatment Hazard Description Hazardous Marine life Hazardous marinelife Health practitioner Heart Attack Heart Health Heart Rate monitor Heart rates Heart rate Heart Heat stress Helium Hepatitis C Hepatitus B High temperatures Hip strength Hip surgery Hippocampus History Hot Humans Hydrate Hydration Hydrogen Hydroids Hydrostatic pressure Hyperbaric Chamber Hyperbaric research Hyperbarics Hypothermia Hypoxia Immersion Immine systems In Water Recompression Indemnity form Indian Ocean Indonesia Inert gas Infections Injections Instinct Instruction Instructors Insurance Integrated Physiology International travel International Interval training Irritation Joint pain KZN South Coast Kidneys Kids scubadiver KwaZulu Natal Labour laws Laryngospasm Learning to dive Legal advice Legislation Leukemis Liability Risks Liability releases Liability Life expectancy Lifestyle Lightroom editing Live aboard diving Liver Toxicity Liver diseas Low blood pressure Low pressure deterioration Low volume masks Lung Irritation Lung function Lung injuries Lung squeeze Lung surgery Lung MOD Maintenance Malaria Mammalian Dive Response Mammalian effect Marine Scientists Marine conservation Marine parks Marinelife Master scuba diver Maximum operating depth Medical Q Medical emergencies Medical questionaire Medical statement Medication Mehgan Heaney-Grier Mesophotic Middle ear pressure Mike Bartick Military front press Mixed Gas Mono Fins Mooring lines More pressure Motion sickness Muscle pain Mycobacterium marinum Nausea Nautilus Neck pain Neurological assessments Nitrogen build up Nitrox No-decompression Non-rebreather Mask Normal Air Nosebleeds O2 providers O2 servicing OOxygen maintenance Ocean Research Ocean pollution Open water divers Orbital implants Oronasal mask Osteonecrosis Out and about Outreach Oxygen Cylinder Oxygen Units Oxygen deficit Oxygen deicit Oxygen dificiency Oxygen ears Oxygen equipment Oxygen masks Oxygen supply Oxygen therapy Oxygen P J Prinsloo PFI PJP Tech Part 3 Partner Training Philippine Islands Philippines Phillipines Photography Physioball Physiotherapy Pills Pistons Planning Plastic Pneumonia Pneumothorax Poison Pollution Pool Diving Post-dive Pre-dive Preparation Prepared diver Press Release Professional rights Provider course Pulmanologist Pulmonary Bleb Pulmonary Edema Pulse Punture wounds Purge RAID South Africa RCAP REEF Radio communications Range of motion Rashes Rebreather diving Rechargeable batteries. Recompression chamber Recompression treatment Recompression Recycle Reef Conservation Reef surveyors Regulator failure Regulators Regulator Remote areas Renewable Report incidents Rescue Procedure Rescue breathing Rescue breaths Rescue training Rescue Resume diving Risk Assessments Risk assesments Risk assessment Risk elements Risk management SABS 019 Safety Stop Safety Sanitising Saturation Diving Save our seas Science Scombroid Poisoning Scuba Air Quality Scuba Injury Scuba Instructor Scuba children Scuba dive Scuba health Scubalearners Sea Horses Sealife Shark conservation Shark diving Sharks Shoulder strength Sideplank Signs and Symptoms Sit-ups Skin Bends Skin outbreak Skin rash Snorkeling Snorkels Sodwana Bay Solomon Islands South Africa Spinal pain Splits Squeezes Stability exercise Standars Stay Fit Stents Step ups Stroke Submerged Sudafed Sulawesi Supplemental oxygen Surface supplied Air Surfaced Surgeries Surgery Suspension training TRavel safety Tabata protocol Tattoes Technical Diving The Bends The truth Thermal Notions Tides Tips and trick Tooth squeeze Transplants Travel smarter Travel tips Travel Tunnelling Tweezers Ultrsound Unconsciousness Underground work Underwater photographer Underwater photography Underwater pho Urinary retention. Vaccines Vagus nerve Valsalva manoeuvers Vape Vaping Vasopressors Vasvagal Syncope Venting Virus infections Volatile fuels Washout treatments Wastewater Water Resistance Water Weakness Weigang Xu West Papua Wet diving bell Wetsuit fitting Wetsuits White balance Wide angles Winter Woman in diving Work of Breathing Workout Wound dressings Wreck divers Wreck dive Wreckdiving Wrecks Yoga Youth diver abrasion acoustic neuroma excision air-cushioned alert diver altitude anemia antibiotics antiseptics bandages barodontalgia bent-over barbell rows bioassays body art breathing air calories burn carbon dioxide toxicity cardiovascular cerebrospinal fluid checklist chemo port child clearances closed circuit scuba currents cuts dead lift decompression algorithms decongestants decongestion dehydration dive injuries dive medicing dive ready child dive reflex dive tribe diver in distress diver rescue diver training dive diving attraction doctors domestic travel dri-suits drowning dry mucous membranes dry suits dry e-cigarettes ear spaces elearning electrolyte imbalance electroytes emergency action plans emergency assessment equalising equalizing exposure injuries eyes fEMAL DIVERS fire rescue fitnes flexible tubing frediving freedivers gas bubble gas poisoning gastric acid gene expression health heartburn histidine hospital humidity immersion and bubble formation immersion pulmonary edema (IPE jaundice join DAN knee longevity lower stress malaise marine pathogens medical issues medical procedures medical risk assesment medications mental challenge micro-organisims minor illness mucous membranes nasal steroids nasal near drowning nematocysts neurological newdivers nitrogen bubbles off-gassed operating theatre operations orthopeadic outgas pain perforation phillippines physical challenges pinched nerves plasters polyester-TPU polyether-TPU post dive posture preserve prevention psychoactive pulmunary barotrauma rebreather mask rebreathers retinal detachment risk areas safety stops saturation scissors scuba equipment scuba single use sinus infections smoking snorkeling. spearfishing sterilising stings strength sub-aquatic swimmers ears tattoo care tecnical diver thermal protection toxicity training trimix unified standards vision impaired warmers water quality