Humans have been using snorkels for centuries. Whether it was sponge farming in ancient Greece or “human submarines” spearfishing in the 1930s, a hollow tube is an intuitive solution for uninterrupted below-water activity. Because the basic idea of the snorkel is so intuitive, most folks don’t give them a lot of extra thought. However, there’s more to how snorkels work than meets the eye. Most modern snorkels don’t look anything like a simple hollow reed, after all!
Modern snorkels are designed to be safe, durable, and easy-to-use. This includes considering the length of the tube for effective gas exchange, ergonomic shapes, sterile comfortable mouthpieces, and special features to help keep water out of the tube.
How Snorkels Work: The Basic Parts of a Snorkel
All snorkels have a few basic components in common. There’s the main tube, a mouthpiece, and a mechanism for attaching the snorkel to a dive mask. The simplest snorkels, often called “classic snorkels” have just these three parts.
In the old days, snorkel tubes were straight with a J-curve for the mouthpiece. Modern snorkels, however, feature contoured tubes that make for a much more comfortable fit around your face.
Regardless of the snorkel tube’s shape, its purpose is to allow gas exchange between your mouth and surface air while keeping your face submerged below the water.
Lungs have evolved to exchange enough gas on each breath to ensure you’re well-oxygenated at all times (unless you have a lung ailment or disease of some kind, of course). However, a snorkel adds a small amount of extra air volume that needs exchanging on each breath. That means your lungs will have to do a bit of extra work to account for this “dead space”. Fully exchanging the air in your snorkel on each breath is best accomplished by breathing deeply.
This is one reason why we can’t make snorkels that are meters and meters long to reach great depths. With a too-long snorkel, stale air that’s high in carbon dioxide from your exhales would accumulate in the tube. For example, European standards limit adult recreational snorkels to a maximum of 38 cm long and 230 mL in volume. Breathing at great depths also requires your air supply to be pressurized (e.g. via tank or pump). Breathing surface-pressure air from a meters-long tube isn’t possible because your lungs cannot inflate against the high water pressure at those depths.
Modern snorkel mouthpieces are made from soft, high-quality silicone (high or pure silicone content). Not only is silicone more comfortable and longer-lasting than natural rubber, but it’s also easy to clean and hypoallergenic. Mouthpieces also tend to be detachable and replaceable (e.g. for cleaning or if you chew out the bite tabs).
All snorkel mouthpieces have a similar design with a flap that makes a seal on the inside of your lips and two bite-tabs for resting your teeth on. Different brands will patent slightly different mouthpiece shapes for improved ergonomics or comfort. For example, some fancy mouthpieces have special bite-tabs with extra soft silicone or even moldable silicone for a customized fit with your teeth. Aqualung has also patented Comfo-Bite mouthpieces for their snorkels and SCUBA regulators, which feature larger silicone panels that don’t require “holding on” with your teeth like traditional bite-tabs.
Ideally, you shouldn’t be clamping down hard on the mouthpiece or straining to close your lips around it. Instead, you should keep your lips and jaw relaxed. If you find a mouthpiece is uncomfortable, it might be too big for you. Mostly, mouthpieces are one-size-fits-all, but there are some snorkels that come with the option for a smaller mouthpiece.
The simplest mask attachment mechanism is a snorkel keeper. A snorkel keeper is just two loops of silicone attached at the center like a figure-eight.
Though many modern snorkels come with fancier clips that allow speedy attachment and detachment, and that pivot in multiple directions for comfort, I still find the simple snorkel keeper the most effective attachment mechanism.
Tip: Keep a spare snorkel keeper or two in your dive/snorkel kit in case you lose one, or if your mask attachment clip breaks!
How Do You Breathe Underwater With a Snorkel?
For snorkeling, breathing deeply is important for getting adequate oxygen. Deep breathing ensures that all the air in your snorkel tube is exchanged each time you breathe.
Have you ever found yourself feeling fatigued or dizzy while snorkeling? Perhaps even a slight headache? This is likely from breathing air with too much carbon dioxide content that’s built up in your tube.
Generally, larger snorkels work well with larger people and vice versa. Larger snorkels have larger volumes, so your lungs must have the capacity to exchange that volume on each breath. If you’re not used to snorkeling or deep breathing, then you’ll better off with lower volume snorkel (shorter and/or narrower).
How Do Classic (“Wet”) Snorkels Work?
In its most minimal form, a wet snorkel is only a silicone mouthpiece attached to a J-shaped tube. Some wet snorkels will also have a flexible tube and a purge valve, though these features are more common on dry and semi-dry snorkels.
Air Exchange is Easier
Because classic snorkels tend to be designed for apneic sports (freediving, spearfishing), they’re often shorter, narrower, and lighter than semi-dry and dry snorkels. That means it’s relatively easy to exchange all the air in the tube on each breath.
Tube Clearance is Challenging
On the other hand, the minimalist design of classic snorkels also means they typically don’t have a purge valve. That means you must be able to expel water out the top of the snorkel if it floods. If you don’t have much practice with tube-clearance, a classic snorkel can be challenging to use.
Classic Snorkels Work Best For Experienced Snorkelers
If you’re experienced with tube clearance and you like duck-diving (diving a few meters below the surface) while you snorkel, then a classic snorkel is best for you. You might also prefer a classic snorkel if you’re interested in freediving or spearfishing. Lastly, some folks (myself included) simply prefer classic snorkels because they’re lighter and more streamlined. If you’ve found that most recreational snorkels you’ve tried feel too bulky or clunky, try a classic snorkel next time!
How Do Semi-Dry Snorkels Work?
The semi-dry snorkel represents something of a compromise between the classic wet snorkel and the dry snorkel. Semi-dry snorkels are characterized by splash guards, flex tubes, and purge valves.
A Splash Guard Helps To Keep Water Out
Splash guards help to keep water from choppy waves, splashes, or spray from getting in through the top of the snorkel tube. The splash guard is typically a molded piece of plastic that sits on top of the snorkel opening. When well designed, angled slits and baffles on the splash guard effectively shunt water away from the opening without impeding airflow.
A Purge Valve Helps With Tube Clearance
Most semi-dry snorkels also have a purge valve. The purge valve is housed in a reservoir below the mouthpiece where excess water can collect. The bottom of the reservoir has a soft silicone mushroom valve that will open when you forcefully exhale to clear the tube. This valve makes tube clearing easier because you don’t have to force all the water out the top of the tube.
Tip: Choose a snorkel where the purge valve is indented into the reservoir somewhat, not exposed on the outside. An exposed purge valve is more prone to accidentally opening due to currents or even quick movements of your head and body.
A Flex Tube Provides a Customizable Fit
Flex tubes can be present on all types of snorkels, but they’re especially common on semi-dry and dry snorkels. The main advantage of flex tubes is that they give you the freedom to adjust the positioning of the mouthpiece, which makes for a more comfortable fit. The mouthpiece will also fall away from your face when it’s not in your mouth. Some folks appreciate this, while others may find the dangling mouthpiece annoying. The only case where a flex tube is a must-have is if you’re using the snorkel during SCUBA activity. In this case, you’ll need the mouthpiece out of your way when using your regulator.
Semi-Dry Snorkels Work Well For Many Activities
Chances are the first snorkel you ever tried was a semi-dry snorkel. They’re accessible to beginners and experienced snorkelers alike. For casual activity, a dangling mouthpiece (from a flex tube) is a plus for occasionally popping above the surface to have a chat with your buddy. Semi-dry snorkels also come in a broad range of styles and sizes, meaning sleeker models can be used for breath-hold sports too.
If you want a versatile snorkel that you can use for almost any underwater activity, there’s probably a semi-dry model out there for you!
How Do Dry Snorkels Work?
A dry snorkel is characterized by a float valve mechanism near the opening of the tube. The float valve seals the dry snorkel if it becomes completely submerged. For example, this might happen if you take a dive or a large wave rolls over you.
A Float Valve Keeps Almost All Water Out
Though the specifics vary across brands and models, all dry valves use buoyancy to open and close the snorkel opening. A buoyant material (a float) attaches to a hinge mechanism that pushes a flap over the dry snorkel’s opening. If the top of the snorkel is submerged, the float mechanism will rise up to close the opening. At the surface, the mechanism opens again, allowing you to start breathing immediately. In other words, dry snorkels almost never need to be cleared of water.
Can You Breathe Underwater With a Dry Snorkel?
Unfortunately, the name “dry snorkel” seems to have created some confusion as to how they work. “Dry” refers to the fact that they don’t get flooded with water when submerged. That does not mean you can breathe underwater with it! You cannot breathe underwater with a dry snorkel if the snorkel is completely submerged. There is simply not enough air trapped in the tube for you to breathe with!
Dry Snorkels Work Best For Surface-Only Activity
Dry snorkels are the best choice for total beginners and anyone who has difficulty with the technique of clearing water from the snorkel tube. A dry snorkel might also be a good choice if you never intend to do any diving with your snorkel. Even though the float valve makes dry snorkels very comfortable and convenient to use at the water’s surface, the air they trap in the tube when submerged makes them cumbersome for any kind of diving. Dry snorkels are buoyant underwater because of the trapped air, which means they can tug on your mask strap awkwardly if you’re scuba diving or freediving, for example.
Related Post: The Best Dry Snorkels (Pros and Cons)
Summary: How Snorkels Work
- Snorkels come in three broad styles: classic (wet), semi-dry, and dry
- The essential parts of a snorkel are a mouthpiece, tube, and mask attachment mechanism
- Semi-dry snorkels have a splash guard and a purge valve
- Dry snorkels have a float valve (in addition to a splash guard and purge valve), which eliminates the need for tube clearance
- All snorkel styles may have a flex tube
- The “dead space” air in classic snorkels is easier to fully exchange on each breath, but tube clearance is challenging due to lack of purge valve
- Semi-dry snorkels are the most versatile and widely available style of snorkel
- Dry snorkels are best for total beginners and surface-only activity
How do different snorkels work out for you? Do you prefer a classic/wet, semi-dry, or dry snorkel? Let me know in the comments!
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