Scuba divers spend a lot of time at the surface. In fact, if you surface swim from the shore, you may spend as much time at the surface as you do underwater. However, there's still life to see at the surface, and snorkels allow you to enjoy it without wasting your air supply.
You should always carry a snorkel, even if you don't plan on a significant surface swim. For example, if you drift far from the boat or entry point during your dive, a long swim may be necessary. With a snorkel, you can alternate your swim between face-down and face-up positions, which is often desirable when muscles become sore.
Snorkels are mounted to your mask strap on your left side. This prevents interference with your regulator, which comes from your right side.
A basic snorkel consists of a curved tube with a mouthpiece. This is called a "J" snorkel, and an example is pictured to the left. Another common design is a flex snorkel. These snorkels allow the mouthpiece to hang away from the face while not in use.
- The mouthpiece must fit comfortably in your mouth without causing jaw fatigue. You hold it in your mouth by biting on two tabs located at each side of the mouthpiece.
- Snorkel Keeper
- Snorkel keepers secure the snorkel to your mask strap, and are available in several styles. They are included with all snorkels, and you can purchase replacement keepers to use as a back-up.
- Flex Tube
- Flex snorkels have a flexible tube between the rigid tube and mouthpiece. They should be flexible enough to bend easily towards your mouth, but firm enough to prevent kinks.
- Purge Valve
- A popular feature is a purge valve located below the mouthpiece. The purge valve allows water to drain through the bottom of the snorkel, which makes it easier to clear water from the snorkel.
- Splash Guard
- A splash guard is an optional feature that helps prevent water from entering the snorkel while you are swimming on the surface.
Snorkel Size and Dead Air Space
The ideal snorkel is about 3/4 of an inch in diameter and between 12 and 14 inches long.
If a snorkel is too narrow, breathing resistance increases. It would feel similar to breathing through a straw. It must also be long enough to not fill with water while on the surface.
Snorkels can be too large as well. A snorkel contains dead air space, which is exhaled air you rebreathe when you inhale. The wider or longer the snorkel is, the more dead air you must inhale with every breath.
Snorkels that are too long are awkward to wear and may become entangled while diving. Additionally, the excess length increases your drag while underwater, which makes it more difficult to swim.