A snorkel is a tube with a mouthpiece designed for breathing underwater. When worn properly, a snorkel keeps water out of a snorkeler’s mouth and air flowing in, allowing the person to breathe without surfacing for air.
How Snorkels Work
At the most basic level, snorkels work by creating a path from a snorkeler’s mouth to the air above the water. The end of the snorkel tube is placed just behind the crown of the head (it requires the use of a mask to hold it in place), making it semi-upright when the person puts their head face-down in the water.
But it gets more complex than that because there is more than one type of snorkel.
A wet snorkel is the classic snorkel, and it works just as described above. It is just a tube and a mouthpiece, allowing air to continue flowing in.
A semi-dry snorkel is much like a wet snorkel, but it has a splash guard at the top and, typically, a purge valve to help clear the tube when the snorkeler gets water in the snorkel. A splash guard helps prevent water from getting into the tube, but it is still possible for it to get in.
A dry snorkel is designed to keep water out completely. Like a semi-dry snorkel, it has a splash guard at the top, but it also has what’s called a float valve.
This float valve responds to water pressure outside of the tube and automatically moves to block the tube when a snorkeler dives under the water. This keeps water from entering the tube.
Full-face snorkel masks combine the mask you wear while snorkeling and the snorkel itself into a single unit. Like a mask that covers the eyes and nose only, a full-face snorkel mask creates a seal against the skin when a snorkeler puts it on, preventing water from getting inside.
A good full-face mask isolates the nose and mouth from the eyes, preventing breath fog from impeding vision.
Since the nose and mouth are both covered by the breathing apparatus, a snorkeler can breathe normally through either the mouth or the nose.
How do you breathe while snorkeling?
Through your mouth alone, unless you’re using a full-face mask.
The mouthpiece of a traditional snorkel tube goes into the mouth, between the teeth, typically with an attached piece that fits between the front of the teeth and the lips, much like a mouth guard used in sports, just not as big.
When the mouth closes, it creates a suction around the mouthpiece that prevents water from flowing in.
A mask that covers the eyes and nose is worn with a traditional snorkel to prevent water from being inhaled through the nose.
To get a feel for just how breathing through a traditional snorkel feels, pinch your nose and breathe through your mouth. It does feel a bit unnatural, but you can see it allows you plenty of air.
With a full-face snorkel mask, you breathe just as you normally would, through the nose or the mouth.
Since air remains trapped inside the mask, these masks circulate the air within to ensure you breathe oxygen and not CO2.
Can you breathe underwater with a snorkel?
Well, yes and no. It depends on what you mean by the phrase “breathe underwater.”
Can you breathe with your face underwater with a snorkel? Yes, you can, as long as the other end of the snorkel tube is above the water. That’s what snorkeling is.
Can you breathe underwater when the snorkel itself is underwater, tube and all?
No, you can’t.
You can dive underwater wearing a snorkel, but you have to hold your breath while you do so. When you do resurface, you have to clear the snorkel by blowing air into it.
With a wet snorkel, the air blows the water out the top of the snorkel tube.
With a semi-dry snorkel, the air blows the water out the top of the tube and also through the purge valve, which opens automatically in response to air pressure and closes automatically when clearing is finished.
Dry snorkels shouldn’t have to be cleared when you resurface after diving. Full-face masks are always dry snorkels.
Since they give you the ability to breathe underwater, snorkels seem like far more advanced technology than they actually are.
Though dry snorkels and full-face masks do contain some advanced features, like float valves and air circulation systems, the basic foundation of a snorkel is incredibly simple – it’s a tube to access air.
Breathing through a straw will give you a good idea of how the most simplistic snorkels work.