Diving below the surface with breath hold diving
Learning breath hold diving will completely transform your snorkeling experience. Getting down to reef level gives a whole new perspective and allows you to see the colours more vividly. You’ll take much better photos too. You’ll be amazed how close you can get to fish, they are not scared, they’ll come to you. You’ll be able to see critters that aren’t visible from the surface, like shrimps and nudibranchs. Reefs that you previously thought too deep for snorkeling now become your playground and you can see 90% of what scuba divers see without the encumbrance of scuba gear.
Swimming under the water with mask and snorkel is called breath hold diving, skin diving, active snorkeling, snorkel diving, free diving or APNEA. The idea is to hold your breath for an extended period underwater. Serious free divers take breath holding to extremes (the current AIDA Static Apnea world record is a breath hold of over 11 minutes and the record depth is 214 metres). But the rest of us everyday mortals are concerned with staying a few metres below the surface for a couple of minutes. That’s enough to safely experience the marine life on their terms.
Duck Dive Technique
Duck diving is the technique used to get yourself underwater smoothly and efficiently without any splashing about on the surface. It’s very easy with a little practice. While swimming on your belly with snorkel in mouth take a lung full of air and hold your breath. Stretch your arms out in front then bend yourself in half at the waist so that your head submerges. Lift your feet above your head and straighten your legs so that you descend vertically head first. Do not kick your fins until they are under the water. You can use a breast stroke with your arms to aid propulsion.
Keep your snorkel in your mouth. It will fill with water so it is important that when you return to the surface your first action is to breathe out therefore purging the water out of the snorkel. You can then continue snorkeling on the surface without interuption. With experience you will learn to start purging your snorkel just below the surface, a very gentle blow will allow the expanding bubbles to clear water from the snorkel by the time you surface.
If you are wearing a wet suit you may need one or two weights on a weight belt to initially get you below the surface. If you have a lot of body fat you will also be buoyant. You should not wear so much weight that you struggle to swim at the surface. Test how much weight you need a little at a time. Float vertically in the water wearing your mask and snorkel and take a breath in. If you are correctly weighted you should float at about eye level. When you breathe out you will start to sink. Your wet suit is full of air pockets that will compress underwater making you less buoyant. You cannot duck dive while wearing a flotation device like a life jacket.
On your first underwater dive you may be surprised to feel your mask squeeze to your face and your ear drums hurt like when a plane lands. This is become of the increased pressure underwater. The pressure at 10 metres depth is double what it is at the surface. If your mask feels tight just breathe out gently through your nose to equalize the pressure, this is why snorkeling/SCUBA masks have a nose pocket. To equalize your ears hold your nose and breathe out gently through the nose. Do not force it. If you cannot equalize ascend and try again.
How long can you stay underwater?
Once submerged the question becomes how long can you stay there? The first attempt will probably be less than 30 seconds, it can be scary to be breathless. But you’ll be amazed how quickly you can improve your times just by repeated practice. Make sure that between each duck dive you get your breathe back fully, take long slow deep breathes, relax and slow your heart rate until you are ready to go again. While under water limit your movement as all movement burns up oxygen. If you want to swim around make slow, steady kicks. It’s best to keep your arms at your side, fish will come closer to you if you stop flapping your arms around. Don’t push your time or depth limits, when you feel the urge to surface, start finning up.
It is possible to extend breath hold time with a technique called hyperventilation. This involves taking several big gulping breathes of air before diving down. When breath holding the body uses the air in the lungs first, then it takes oxygen from the blood. The brain receives a signal to breathe again not when oxygen expires but when carbon dioxide levels are too high. Taking lots of deep breathes flushes out CO2 so the brain is “tricked” into not breathing until later. But if the O2 runs out before the signal to breathe is received the brain shuts down. This technique can be extremely dangerous. You can black out without any warning and drown. Do not practice hyperventilation. Always go diving with a friend. If you are interested in learning advanced free diving techniques we can recommend some freediving schools.
How deep can you go?
How deep you can go on one breathe of air mainly depends on how long you can hold your breath for. Once you can equalize your ears to descend a few metres you should be able to swim to 10 metres with no physical discomfort, just leave enough are to return to the surface.
We have already discussed the importance of not hyperventilating before duck diving, leave the limit pushing free dives to the trained pros.
It is recommended to always go snorkeling with a partner in case you get into any sort of difficulties.
Try not to touch anything on the reef. Marine life will generally leave you alone unless you harrass it. Some coral can burn and sting, some camouflaged fish are highly venomous, even shells can kill. If you want to grab a rock for support underwater look very carefully before touching.
When surfacing after a free dive look up towards the surface to make sure that you don’t crash into any other swimmers or worse, a boat hull. Turn around as you ascend to check all directions. Remember that boats can’t see you underwater so snorkel in safe areas away from boat traffic. You will be able to hear boat noise underwater but direction can be misleading.