Sinking while freediving, (or free falling), is an absolutely fundamental part of the sport. For a lot of free divers, the free falling is actually the most beautiful and rewarding part of the dive. Imagine yourself flying upwards through the sky, and the freedom you will feel as you begin to feel more and more weightless.
Freefalling is essentially just the exact reverse of this, as you allow yourself to sink deeper, with usual laws of physics suddenly not seeming to apply to you. The experience is unnervingly freeing. It is one of the integral things that people fall in love with, and if you can get it right, you can actually buy yourself more time, and a much smoother dive in general.
So how do you sink when freediving? How is it physically possible? Don’t humans normally just bob back up to the surface of the water? What are the main things to remember? Is it complicated?
This article breaks down how to sink while freediving into manageable and understandable chunks, to help you through the process.
Empty your lungs.
This may sound baffling to anyone who is not used to freediving. Surely, to spend longer underwater you would want as much breath in your lungs as possible? The issue with this is that a pair of lungs full of air will make you buoyant, which will bring you straight back up to the surface. Emptying your lungs makes your overall volume far less dense, than that of the water surrounding you, and this helps you to sink below the surface without rising back up.
Your lungs need to be emptied sufficiently for this to work, and it isn’t as simple as it may sound either. In the freediving world, the breathing preparation is called a ‘breathe up’ which involves getting your body relaxed and slowed down, which will give you a better dive.
First of all, you should not do any more than two complete breaths before you dive, or else you are at risk of hyperventilating. Make sure that you have a longer exhale than inhale. This tricks the body, because when we exhale, our heart rate decreases. If we extend the length of the exhalation, even if it is only for a brief moment, this means that we can calm the body and mind, and reduce our oxygen consumption.
At the end of the inhalation and exhalation, pause. Ensure that the pause at the end of your exhalation is longer than the pause at the end of the inhalation. This also helps to slow the breathing rate down, again, reducing our oxygen consumption.
Keep the breathing relaxed, so that you do not strain your intercostal or stomach muscles. Again, this keeps your heart rate low, which is key for freediving.
Find Your Neutral buoyancy.
What you want, is to achieve something called neutral buoyancy. Neutral buoyancy is the key to free falling, and without it, freediving is rendered essentially obsolete. It occurs when an object’s density is equal to the density of the fluid surrounding it. This results in the buoyant force being equal to the force of gravity, which would make it sink.
If an object has achieved neutral buoyancy, it means that it will neither sink nor rise. If you think about it, your body naturally will rise to the surface of the water if you do not struggle to keep it under. This means that your body has positive buoyancy. If, however, you dropped a heavy rock into a pool, it would undoubtedly sink to the bottom.
This means that the rock has negative buoyancy. As a freediver, we want to be neither of those things. If we have negative buoyancy, that means that we will have a dangerous and difficult time resurfacing. However if we have positive buoyancy, it essentially means that we can’t dive. Neutral buoyancy puts the power in your hands, and allows you to completely control the direction that you go in.
You can then carry or attach your weights to your body to pull you under, knowing that your body will not keep trying to float back up to the surface.
If any of you remember your physics lessons from school, you may remember studying someone called Archimedes, who ran down the street naked shouting ‘Eureka!’ While some of those details have not entirely been legitimatised, it is true that Archimedes, an Ancient Greek mathmetician, discovered the laws of buoyancy.
Supposedly this happened while he was in the bath, which is where the naked running tale comes from, but the take home idea from Archimedes is that a body immersed in fluid is subjected to an upwards force that is equal to the weight of the displaced fluid. This theory is what helped to develop buoyancy aids, and without which, we would be at quite a loss when it comes to understanding free falling.
Use your Weights.
Realistically, your weights will be the biggest element in your dive being deep enough. Finding the right weights can be tricky, since everyone’s bodies are composed so drastically different. Freediving is not just about body mass index, but also takes into consideration our muscle density, bone density, lung volume, fat content, and more. A lot of finding the right weights will involve trial and error, therefore the important thing to remember is to start small.
A rough guide for the average sized person (though that is very variable), will also vary depending on suit thickness. This includes:
-3mm: 1-2 kg/ 2-4 lbs
-5mm: 3-4 kg/ 6-8 lbs
-7mm: 5-6 kg/ 10-12 lbs
Generally though, you can test how much weight you should be carrying before performing the free fall. If you get into the water and stay on the surface, you can play around with different weights, testing how much weight will still keep you afloat after your inhalation.
Overloading your weights can limit your dive and have dangerous repercussions. First of all, being overweighted makes it harder to rest on the surface, and breathe up properly before your dive. In limiting this, you will result in a shortened breath hold, and therefore have a shorter and more limited dive.
Secondly, if you blackout and your diving buddy goes to get you, the extra weight will make it harder for them to assist you and bring you back to the surface, which could lead to health implications. While it may be tempting to add more weight in order to get a better dive, it is far more likely to have the opposite effect. So start smaller, and build gradually.
Get your body into the Right Position.
Even when all your breath work is done, there is still a lot to do on the surface. You should flood your wetsuit to make sure that there are no air bubbles trapped inside. After all of that work to empty your lungs, you certainly don’t want any oxygen hiding inside of your wetsuit either!
Then, to get started with the free fall, you will need to be facing down towards the bottom of the water. Keep your body in a straight line, with your arms at your sides, ad your knees slightly bent. You want to maintain a relaxed posture, and your head should stay looking straight ahead, not up, down or to the side. You can kick your legs to propel yourself down faster.
When you reach your neutral buoyancy level, your body should begin to sink to your desired depth. Your neutral buoyancy level will be at around 10-15 metres, which is around 32.8-49.21 feet. At this point you should give two final, slightly stronger kicks, or arm strokes. This is known as CNF. It is important to conserve your energy as much as possible at this point, and since you have reached your neutral buoyancy point, struggling against the water will not be necessary.
Once you stop kicking, you should change your posture, to be as streamlined as possible. This means stretching your knees, your ankles, keeping your head neutral, and your neck aligned. Slightly tuck your chin into your chest. This aids equalisation, and prevents against trachea squeeze. Slightly round your shoulders forward, and relax your belly. This releases any tension in the upper body, and allows you to relax, which is key.
While you were kicking, you will have held a more relaxed posture, and your legs were moving, however, now you need to be steady and still. A lot of free divers like to have their arms outstretched in an arrow position, however, they do not have their arms actually aligned with their body. This only actually results in a loss of energy and tension in the shoulders, meaning it is not always worth your while. Your focus should just be on keeping your body in a perfectly straight line, to stay as streamlined as possible.
If you are holding onto the line while freefalling, keep a loose hold with your index finger and your thumb. Do not hold on too tightly, as this will drag you, and make you fall slower. Do not have your arm over the top of your head to hold the rope. Instead, keep your arm by your side, and the rope running down the side of your body near to your shoulder.
Stay Safe and take someone with you.
Before you get in the water, before you buy the equipment, before you even consider where, why or how you might want to freedive, you have got to ensure that there will be somebody there with you. Diving alone exponentially increases your risk of death, and many of the free diving deaths and incidents which occur when someone dives alone are not even recorded.
Take someone with you, and make sure that they have the right diving equipment to assist you if they spot you struggling. It can be a matter of life or death.
Once you understand the steps, it is important to find the right equipment. In a sport which can be as lethal as freediving can be, it is not possible to cut corners when finding your equipment. It is far better to wait a while until you can afford everything that you need before giving it a go, rather than potentially ending up paying with your life instead.
While it may sound morbid, the free diving death rates for recreational dives are astoundingly high compared to other diving or water sports, so it is important to take it seriously. Have a watch of this video to get a good understanding of what is needed, and then read through my recommendations of some good brands:
- A buoy and lines. This is for you to hold on to while at the surface, and are absolutely essential to help you to breathe up, and preserve your energy between dives. Think about it, do you really want to tread water after holding your breath underwater for four minutes, and before preparing to do the same thing again? The XS Scuba Universal Floating Object is a good option, since it also comes with its own flag and line, which help ships see you, and prevent any collisions with them.
- A free diving computer. This is good to track your free diving depths, which is good for personal growth, and also to make sure that you aren’t attempting to go too far. It also sound alarms to prevent you from going too deep or running our of oxygen, therefore also preventing issues such as decompression sickness, and most importantly, blackouts. The Oceanic F10 Free diving computer has water temperature recordings, alarms, depth tracking, surface interval recording, and much more. It is specifically tailored to free diving as well, which is much better than getting a scuba diving watch for example, and trying to use it for free diving.
- An Air Restriction Device (ARD). As we have covered, your breathe up is one of the most integral parts of your free fall. What a lot of people don’t realise is that your lungs and diaphragm are like muscles which can be trained up over time. ARDs are small, hand held devices which are used to train your lungs and breathing muscles, therefore allowing you to breathe up better, and dive deeper. The PowerBreathe Plus 2 Fitness is internationally famous within freediving communities to dramatically improve your breathing muscle strength and stamina. Like a lot of free diving equipment, it is costly, however, entirely worth it if you are serious about free diving responsibly.
- Monofins or Bifins. As we also mentioned earlier, to free fall before you find your neutral buoyancy, you will be best to kick. All free diving fins essentially serve the same purpose, with a closed rubber heel, and a long blade design, to propel you further down. The Beuchat Mundial Elite Freediving Fins have a stiff full foot construction with dynamic propulsion, ideal for providing both comfort and power.
- A Wetsuit. Even though it may seem warm on land, the deeper that you sink, the colder that the water will become. A Cressi Apnea Neoprone winter wetsuit with a thickness of around 7mm will keep you warm in the water. Keeping warm is not just for general comfort, but for your breathing as well, because you do not want to hyperventilate, or do anything that could lead to a blackout.
- A Weighted Belt. The most popular choice for beginner free divers is the rubber weighted belt, which fits tightly around the hips, and therefore does not interfere with any belly breating or diaphragmatic breathing, and you can then attach your weights there. Other, more experienced divers may prefer a neck weight, either instead of or used together with the waist weight belt. The neck weight streamlines the body, and helps with the correct body positioning during freefall. However, strong neck muscles are important to avoid any injury, therefore neck weights are absolutely not recommended for anyone who is not an advanced free diver. This Riffe Rubber Weight Belt with Nylon Buckle is a good 5place to start.
- A Mask. Obviously, your face cannot be exposed when you are free diving, and this is actually one of the most essential pieces of gear. If your mask leaks, holds too much volume, or provides a challenge to equalise, it will massively impair your dive, which again, could be fatal. The Cressi Nano 2 is compact and dynamic, and is one of the most popular free diving masks around. Made from high quality silicone, split-type straps, and easily adjustable buckles helps it to naturally cut through water as you swim, fall, or navigate small, tight spaces.
- Ear plugs. In free diving, you do not swim as deep or for as long as you would for a scuba dive, however it is important to still equalise your ears early and frequently to avoid an ear injury. Too much or too little pressure in the middle chamber of your ear can lead to barotrauma, which is not only painful, but will limit you diving in the future. Free diving ear plugs are actually vented, which compensates for any changes in pressure inside or outside your ears while freediving, while regular earplugs (meaning any type of ear plugs that are not specifically designed for free diving) create a sealed area of air inside your ear that cannot be equalised. This means that if you think you do not need to splash out on a good free diving pair, because you have some random ones lying around at home somewhere, you are mistaken. Doc’s ProPlugs Vented Ear Plugs are vented, and specifically designed for free diving, and are not that expensive either, when you think about what you are paying to avoid.
Why is it necessary to Freefall?
For a lot of swimmers, it is confusing as to why we can’t simply swim downwards, why is it necessary to go through all of that when we could swim? Simply put: we do not have the energy or oxygen supplies to be continually moving our bodies throughout the entire dive. Free falling allows us to conserve our oxygen by limiting muscle activation massively, which therefore places more emphasis on our body relaxing, which is essential for a good dive.
Also, the science-y part aside, free falling is actually really fun! Chances are that you have already tried swimming, and scuba gear can feel quite overbearing and restrictive. Free falling literally allows you to let go, and relax your body as much as you physically can, and then just… fall. It can’t even really compare to the free falling of a skydive or bunjee jump either, because in the water you are truly in your own world, and it creates quite a dream-like experience with the water rushing past you.
So hopefully this has shed some light on the mechanics of how to master free falling when diving. It is important to understand the physics of what you are about to do before you attempt to do it, and make sure that you are well equipped with everything correctly, in order to avoid an injury that is likely to completely put you off free diving altogether.
Make sure to read the advice carefully, and if you have any queries, speak to a trained diving instructor for help. While it is technical, it is entirely worth it once you understand the foundations of free fall, and it will bring to you an experience which you will never forget.