28 tips to conserve air when scuba diving; easy techniques to extend your dive time safely
I’m a big guy so I need to know how to conserve air while scuba diving, I’m 6’6″ tall and weigh around 113 kilos (249 lbs). Which means I’m much bigger than the average person. Why is that important? It’s important because I’ll consume more air than the average scuba diver. So with diving; size does matter! Sex matters too, but more of that later in the article.
Learning how to conserve air while scuba diving is one of the most important techniques to master. Mastering this will make your air last longer and will extend your dive time. The list of air saving tips I've created also includes tips to extend your dive time too.
Quick read tips to conserve air when scuba diving; Also includes extending dive time tips too:
- Keep warm and wear the correct insulation;
- Check your air contents gauge when you connect your dive tank to your regulators (Dive time extending tip);
- Use your own breath to fill your buoyancy control device (BCD) before you jump in;
- Check your equipment for leaks;
- Dive with the correct amount of weight;
- Use your snorkel on the surface;
- Be the last diver to leave the surface;
- Don't empty your BCD completely at the surface;
- Carefully slow your descent as you approach the bottom as you do with a car approaching a junction;
- Get your buoyancy right and leave your inflator alone;
- Adjust air in and air out of your BCD by using tiny amounts;
- Learn to relax and stay calm;
- Breathing correctly - slowly and deeply (Tip comes with a warning);
- Use your lungs for buoyancy;
- Streamlining your body;
- Take everything slowly;
- Dive shallower than the main group;
- Use great fins;
- Always swim with the current, not against it;
- Diving more leads to breathing less;
- Stay fit or get fit;
- Lose a few extra pounds;
- Trim your kit.
- Use a bigger dive tank - use a 15 litre (100 Cubic Foot) cylinder (Dive time extending tip);
- Use a twin set (Dive time extending tip);
- Sex plays a role in scuba diver air consumption;
- Using your buddy's alternative air source (Tip comes with a warning);
- Consider switching to a rebreather, not something I've done, but considering it (Dive time extending tip).
The context of why my techniques are worth noting for how to conserve air while scuba diving
For context and why I've had to master how to conserve air while scuba diving; I'm 27% larger than the average scuba diver. I stand in at 6'6" tall and weigh 249 lbs!
This means that I'd need to dive with a 15 litre (100 Cubic Foot) dive tank to stand a chance of my air lasting the save time as the average scuba diver.
However, most places I only dive with the same 12 litre (80 Cubic Foot) dive tank as everyone else. This is why my list is so long. Some you may already know, some perhaps not. But they work for me, as I tend to consume my air on average the same as the average scuba diver, despite being 27% larger.
The two main ways in which we consume air when scuba diving:
- The first is the air we breathe.
- The second is the air we use to remain neutrally buoyant.
If you aren't able to be as efficient as possible with both of these forms of air consumption, you'll not be able to conserve air and extend our dive time. But more importantly, the longer the dive time, the more fun you'll have diving!
But firstly, let's take a look at how scuba divers breathe underwater.
How do scuba divers breathe underwater?
Breathing when scuba diving for the majority of divers is achieved by using a standard aqualung. The basic kit for an aqua lung is a diving tank (either 12 or 15 litre (80-100 Cubic Foot)), together with a set of regulators (the bit that connects the air in your tank to your mouth so you can breath).
The air is delivered to your mouth via a mouth piece (the regulator or demand valve (DV)), which supplies air on demand. Hence the name 'demand valve.'
This means that there's only a finite amount of air for your dive. So for me, if there's anyway to conserve air or make my air last longer, then I apply any technique I can to all my dives.
Safe ways to conserving air when scuba diving, where conserving air begins on the boat or on land, before you jump into the water...
Tips to conserve air when scuba diving
1. Keeping warm by wearing the right protection and insulation
If you're cold, your body needs more energy to stay warm. Our bodies consume more oxygen when we burn energy, to help create that warmth. This is referred to as respiration.
It makes sense therefore that if we can keep our bodies warm, we'll burn less energy and therefore require less oxygen to fuel our bodily warmth.
Therefore, by keeping warm on a scuba dive by wearing the correct clothing or insulation (i.e. the correct thickness wetsuit or moving to a dry suit in colder waters), we'll require less oxygen and therefore use up less air.
Conclusion for air conservation tip 1 - Keep warm when you dive by wearing the right insulation, to conserve energy and use less air.
2. Check your air contents gauge - Dive time extending tip
When you first connect your regulators to your dive tank, you should always turn your air on and check your contents gauge.
This check serves two main purposes; the first is to make sure your regulators are in good working order. The second reason is to check the air contents of the diving tank.
If the contents are lower than it should be, change the tank for a new one. Check this new dive tank to make sure this has been filled correctly with air. If you start your dive on a dive tank that's less than full, you're automatically going to shorten your dive time.
Conclusion for dive time extension tip 2 - Check your dive tank contents when you first connect your regulator, to make sure you start your dive with as much air as possible.
3. Putting air into your BCD - Using your breath
Right from the start, my mind is on how I can conserve my air, even before I've jumped into the water. So conserving air starts on the boat.
When you're putting your kit together, you need to check the connection of the air hose to your buoyancy control device. When you do this, use as little air as possible, using just enough to see that it works.
Before you jump in the water you need to fill your BCD with air. So instead of using your air hose to do this, use the mouth piece instead and blow the BCD up with your own breath.
Conclusion for conserving air using tip 3 - Use as little air as possible when checking hose connections and use your own breath to fill your BCD before jumping in for your dive.
4. Check for leaks - Make sure your kit's not leaking air
Sometimes dive kit develops air leaks. These leaks will waste air on the dive. So always check that your hoses and your BCD have no leaks before you dive.
Having your kit serviced regularly also makes sure that leaks are kept.
Conclusion to conserving air tip 4 - Always check for lair leaks to avoid wasting air via leakage.
5. Diving with an over-weighted weight belt
For more efficient diving it's best to always dive with just the right amount of weight on your weight belt. The amount of weight you have will be affected by the insulation you are wearing too. The thicker the wetsuit, the more weight you'll need.
Diving with too little weight will cause you problems descending at the start of your dive. It will cause problems at the end of your dive, where you could ascend too quickly at the end.
Whereas, having an over-weighted weight-belt will mean you'll have to compensate the excess weight, by putting more air into your buoyancy control device to maintain neutral buoyancy.
Conclusion for air conservation tip 5 - Always wear the right amount of weight on your weight belt. Never be 'over-weighted' on a dive or you'll use more air to maintain neutral buoyancy. Having the correct weight will mean less air consumption.
6. Use your snorkel on the surface
Most divers don't use their snorkel at the surface, but instead immediately put their regulator into their mouth on the surface. However, I always use my snorkel, which is permanently attached to my mask.
You can sometimes spend 5-10 minutes waiting on the surface, especially if you're one of the first in.
If you're first in and if you're diving in a group that descends together, using your regulator at this point will use up valuable air.
So instead of using your regulator on the surface, always use your snorkel to breath. If the water is clear enough to see the bottom, you are effectively snorkeling. In this time you will often see things whilst you wait. I've seen turtles, sharks and other creatures this way, whilst all the time conserving my air for the dive itself.
Conclusion for conserving air tip 6 - Use your snorkel on the surface so you don't use your dive tank air until you begin your descent. Thereby saving as much of your air as possible for the dive itself.
7. Be the last to leave the surface
Leave your snorkel in until the very last minute. Wait for all the other divers to leave the surface first. Then once you drop below the surface yourself, dive down quickly and efficiently.
This way your're not left waiting for divers that faff on the surface consuming valuable air just below them.
Conclusion for conserving air tip 7 - Always be the last to leave the surface and leave your snorkel in to the last minute. This way you're the last to start consuming your air. This will help to extend your dive time as you started your air consumption last in the group.
8. Don't empty your BCD completely at the surface
If you are able, leave some air in your BCD at the surface. This will mean putting less in it as you approach the bottom to gain neutral buoyancy. Use your lungs as much as you can to help reduce your buoyancy at the surface by breathing out.
Also, to help start your descent, perform a surface dive (duck dive), as you would when snorkeling. This will overcome any added buoyancy you have to get you below the surface. As you surface dive, breath out at the same time. These two actions will work together to get your descent going.
Conclusion to air conservation tip 8 - By not emptying your BCD at the surface, you'll need less air to gain neutral buoyancy at the bottom, thereby conserving air.
If you approach the bottom slowly by using your BCD as a brake, you will use less air than you would by waiting until you are nearly at the bottom and pumping lots of air in to slow down quickly.
This is a bit like when you approach a junction in a car. As you approach the junction, you gradually apply the breaks bit by bit so you arrive at the junction slowly. However, if you wait to the last minute to apply your brakes, you may not stop in time, but you may also skid. You'll wear your brake pads out sooner too.
Apply these same techniques to slowing yourself down as your approach the bottom. What'll happen if you leave it too late to begin inflating your BCD, is you may bump into he bottom (which is not good, especially if it is coral you bump into).
You'll probably also pump too much air into your BCD. This will in turn make you over-buoyant, so that you'll begin to ascend again. To compensate you'll need to dump some air, which is a waste of air. And so on, and so on.
Conclusion for conserving air tip 9 - Carefully slow your descent as you approach the bottom by inflating your BCD using small amounts of air. Do this as you would in applying brakes on a car approaching a junction. This avoids over-inflating your BCD, which is what may happen if you leave it too late, thereby conserving your air.
10. Get your buoyancy right and leave your inflator alone
Not getting your buoyancy right is a major drain your your air supply. Get this right and you'll conserve air.
There are two reasons why uncontrolled buoyancy has an impact on air consumption. The first of these relates to using excessive energy on the dive. One of the best ways to conserve your air when you're diving is to move as slowly and as calmly as possible, using as little energy as you can (See separate tips on this below).
If you don't have your buoyancy under control, you'll either be vigorously kicking your fins to stay off the bottom, or to stop yourself from sinking to oblivion on a deep drop-off dive. Alternatively, you'll be fighting to stay down, where you're over-buoyant, to prevent yourself from floating to the surface.
Neither of these are good, and both will mean you use more energy that you should. Using more energy means you'll consume more air. Consuming more air means your air runs out much quicker and your dive time will be curtailed. So mastering buoyancy is key to conserving air.
Air is required to equalise your buoyancy
The second reason why uncontrolled buoyancy has an impact on your air consumption, is you'll end up using more air to equalise your buoyancy.
Where you're in control of buoyancy, you should be able to slowly inflate your buoyancy control device as you approach the bottom or dive depth of your choice (see previous tip), and then leave your inflator hose alone until the end of the dive.
The only reason you should be touching either your inflator hose or your dump valves, other than using the dump valves on your ascent at the end of the dive, is if you change the depth of your dive at some point during the dive.
Learn to set your buoyancy correctly when you arrive at the bottom or chosen depth of the dive, then leave your BCD controls alone. If you're having to constantly add air to or dump air out of your BCD, you're doing something else wrong.
Which could relate to the following tip.
Conclusion for air consumption tip 10 - Master buoyancy to save energy and avoid excessive breathing, but also to avoid excessive use of putting air into and dumping air out of your BCD. Both of these will have a major impact on reducing your air consuption on your dives.
11. Adjust air in and air out of your BCD by using tiny amounts
The art of buoyancy is all about control. Which is about mastering the use of the controls on your BCD. There are two controls to your BCD, which are air-in and air-out.
Controlling your inflator hose on your BCD
When you are using your BCD to increase your buoyancy (i.e. air-in), which will be when you're descending, you need to master the art of putting just tiny amounts of air in at a time. Your buoyancy takes a few moments to correct itself, so you need to manage this carefully and slowly.
By putting tiny amounts of air in each time, you only use the right amount of air to correct your buoyancy. Whereas, if you are over zealous with your air-in inflation, you'll probably over inflate your BCD and end up having to dump some air to corrected the over inflation. Doing this uses up precious air, which could have been used to extend your dive time instead.
Controling your BCD air dump valves
This leads onto controlling the amount of air you dump from your BCD.
The only time you should dump air and not be to concerned about a 'fast-air-dump' is when you're approaching the surface after your three minute safety stop at six metres (20 feet).
In your final few metres or feet of a dive, your ascent rate will increase. This is due to the rapid change in pressure at this depth (i.e. the pressure halves between 10 metres (33 feet) and the surface).
To slow this increasing descent down, you'll need to dump more air, to avoid ascending too fast, which is okay. Also, bearing in mind this is the end of your dive anyway, so conserving air at this stage of your dive is no longer your priority. Your priority now is to ascend safely and slowly.
Other than at the closing stages of your dive ascent, at all other times the amount of air you dump from your BCD should be in small controlled amounts. Learn to control this carefully, to avoid 'over-dumping' air, which will make you too negatively buoyant. This will result in having to add air to your BCD, thereby wasting precious air.
Practice and be patient with your buoyancy control
Don't get frustrated with your buoyancy if at first you can't seem to get it right.
If at first you don't succeed, try and try again!"
After a while, and by adopting the tips in this article, it will become natural to you. Like learning anything new, it takes practice. Be patient and over time, just like learning to walk or to ride a bike, this skill will come to you.
Conclusion for tip 11 to conserve air when scuba diving - Learn to control the amount of air you put into your BCD and dump from your BCD to tiny amounts each time. This will reduce the amount of air you use to control your buoyancy whilst diving, thereby reducing the amount of air you use. Resulting in an extended dive time.
12. Learn to relax and stay calm
One of the best ways to conserve your air on a scuba dive is to stay calm and relaxed. When you're not calm or relaxed you use more energy. When you use more energy you breathe more and you'll use more of your air.
Many beginner scuba divers are nervous when they start to scuba dive. This means they won't be relaxed. Any anxious state will result a higher heart rate, leading to a higher respiration rate.
Both of these will lead to a higher air consumption because with a higher heart rate and respiratory rate our bodies need more oxygen, as our bodies are expending more energy. As a result of this, more air will be consumed on the dive.
There are ways to help you relax on a dive. The first of which is to enjoy it. Diving should be fun and exciting. Sometimes by changing what we focus on, we change our mind state. This in itself can lead to a more relaxed state.
Learning to meditate or use self hypnosis can work well to relax the mind. If you are really struggling with this problem, consider using a hypnotherapist or psychotherapist to help you change your way of thinking, or your thinking style.
Conclusion for tip 12 to conserve air when you scuba dive - By learning to relax and stay calm will mean your body will use less energy. A body that uses less energy requires less oxygen for respiration. With a reduced respiration rate you will use less air on your dives and extend your dive time as a result.
13, Breathing correctly - Slowly and deeply (Tip comes with a warning)
WARNING: When you control the way you breath underwater; Never hold your breathe and don't over extend your lungs when you breathe in.
How do you breathe when scuba diving?
Scuba divers who are good at underwater air consumption are mindful about their breathing technique.
It's about paying attention to the way you are breathing. Breathing on land is one of the most natural things we do.
Most of the time we don't actually think about it, like we don't think about our heart rate. However, unlike our heart rate, we are able to control our breathing.
However, there are exceptions about being able to controlling heart rate, but that's a bit too deep for this article! If you've not done yoga or meditated before, you'll not be familiar with conscious breathing techniques. However, it may serve you well to learn about this, as it will have a positive impact on your air consumption when you dive.
Learning to control your breathing correctly could be one of the easiest ways of conserving air when you dive.
The way you breathe when scuba diving will be slightly different than when you breathe on land. On land we have no need to conserve our air, whereas underwater we do.
As noted in the above warning, never hold your breathe when you're diving. Also, don't over extend your lungs when you breath in.
Conclusion to tip 13 on conserving air on a scuba dive - Learn to control your breathing and conserve your air. Breath deeper and more slowly, thereby allowing your lungs to extract as much oxygen from the air as they can. But never hold your breathe!
14. Use your lungs for buoyancy (Tip comes with a warning)
WARNING: When using this technique, never hold your breath, as this is dangerous and can cause serious injury. Also, never use this technique to change depth of more than a few feet.
Your lungs represent a large buoyancy chamber. You'll find that as your lungs fill with air, you'll become more buoyant. Whereas, as your lungs deflate, you will become less buoyant.
Using your lungs carefully on a dive to adjust your depth is a common trick used by scuba divers. This avoids using you BCD to control those small ups and downs when exploring the bottom. It can also save a small amount of energy, where the alternative is to fin or use your arms.
If you want to dip down to look under a ledge or under an overhang, using this technique works well. Simply exhale air from your lungs as you manoeuvre into position. To maintain this lower position in the water, don't use such large intakes of breath.
Conclusion for tip 14 to conserve air when scuba diving - Use your lungs as buoyancy control to avoid using your BCD air. You are naturally breathing in and out in any case, so by careful control of your breathing at certain points in your dive will help with your depth. Don't use this technique to change depth by more than a few feet!
15. Streamlining your body
Moving through water is more difficult than it is through air. Water is around 800 times more dense than air is, so the resistance is more.
If you've ever tried to wade through deep water, you'll know how hard this can be.
Think about this concept when you are swimming underwater. Streamlining your body by having your arms down by your sides and keeping your equipment tucked away in neatly, will help with your streamlining. Always swim horizontally in the water and make sure your buoyancy is under control.
If you're more streamlined, it will take less effort to swim. As a result you'll use less energy and consequently, less air too.
Conclusion for tip 15 on conserving air underwater - As water is 800 times more dense than air, being streamlined is important to reduce drag on your body and equipment. Therefore streamline yourself to reduce drag, save energy and use less air.
16. Take everything slowly
A related tip to the last one. As water is so dense compared to air, it's important to take things slowly. The slower your movements, the less energy you'll need to complete each task. This includes swimming slowly, turning slowly and slowing down every other action performed underwater.
Imagine for a moment attempting to run through knee high water. The amount of effort and energy to do this would be many times that required to run on flat ground. This same principle applies to when you are scuba diving. But in this case, instead of being only knee high on water, you are completely surrounded by water.
Taking things slowly will require less energy and need less oxygen in your body to move. This in turn will reduce your air requirement and mean the air you have will last longer.
Conclusion for tip 16 on conserving air underwater - Take everything slower underwater than you do on land. Water is 800 times more dense than air so to moving takes more effort and more energy to do. Moving slower, reduces the amount of energy required and therefore the amount of air you consume reduces as a result.
17. Dive shallower than the main group
The depth you dive to has an impact on the amount of air you consume. The deeper you dive, the more air is consumed.
So when you're diving in a group, consider adjusting your depth slightly and swim above the rest of the divers at a shallower depth. By doing this you are unlikely to miss much and so long as you are still within a few fin strokes of your dive buddy or the group, this is safe to do.
I wouldn't recommend you dive at a drastically different depth to everyone else, as this would not work. But there's nothing wrong in diving at 1-2 meters (3-7 feet) shallower.
This will result in a slight reduction in the amount of air you consume on the dive. It will extend your dive time too.
Conclusion to tip 17 on air consumption improvement whilst scuba diving - Dive at a slightly shallower depth to the rest of your dive group, which will reduce your air consumption. Using less air will extend your dive time.
18. Use great fins
The main form of propulsion underwater as scuba divers is using our fins. If the fins we have are not as efficient as they could be, you'll use more energy swimming. Using more energy underwater means you consume more air and reduce your dive time.
Consider buying some better fins to improve your swimming efficiency.
Conclusion for tip 18 on improving air consumption underwater - Check how efficient your fins are as these are your main form of propulsion underwater. Improving your efficiency, will reduce how much energy you use. Conserve your energy and you'll reduce your air consumption underwater.
19. Always swim with the current, not against it
Often times when we dive there will be a current underwater. Even where the current is only slight, you are better off swimming with the current rather than attempting to swim against it.
As already discussed, water is 800 times more dense than air, so even without a current to swim against, it's hard work. Add a current and this becomes really hard work.
Swimming with the current or diving on a drift dive in particular is fun to do. You are pushed along with the water flow and it's like flying. Where the current is strong enough, you'll save loads of energy, as you don't have to fin at all.
Swimming with the current, rather than against it, will conserve energy and therefore conserve your air.
Conclusion for tip 19 on how to conserve air when scuba diving - Always swim with the current, rather than against it to conserve your energy. Doing so means using less air and therefore extend your dive time.
20. Diving more leads to breathing less
There's no doubt that diving more improves your air consumption whilst diving.
If you've ever been on a dive boat then you'll know that most, if not all, dive masters use hardly any air at all.
This is partly because most are extremely fit, but also because they dive day in, day out. As they dive so much, breathing underwater becomes much more natural to them. As a result, their air consumption improves. Many of the scuba dive masters I've dived with use one tank for my two tanks for two dives. This means they are twice as efficient as me at breathing underwater.
This goes to say, to improve your air consumption on your scuba dives, you simply have to do more dives. Not such a bad thing, if you have the money to afford it.
Conclusion for tip 20 on ways to improve air consumption whilst scuba diving - Diving more will improve your air consumption.
21. Stay fit or get fit
By being physically fit your body will be more efficient, and as a result consume less oxygen during its respiratory process. This will mean your air consumption will improve, the fitter you become.
You've probably been unfit at some point in your life, or perhaps you are unfit now. In a state of 'un-fitness,' I'm sure also you've walked up a flight of stairs. By the time you get to the top (or if you're really unfit, part the way up), you get out of breath.
Think in terms of how dense water is, i.e. 800 times more dense than air. If you are unfit and you have to swim underwater, you will get out of breath more quickly.
Your inefficient body will consume more oxygen than a fit body would, and therefore your air consumption will be higher.
If you are unfit, or could be fitter than you are, consider starting up a fitness regime, as this will make you healthier and it will improve your diving air consumption too.
There are other benefits of getting fitter when you dive. Diving is a strenuous sport, there's getting onto and off the boat. Carrying the kit also take energy, not to mention swimming through water on the dive. So by improving your fitness will make all these activities less of a physical challenge for you too.
Conclusion for tip 21 on consuming less air scuba diving - Staying fit or getting fit will help with the strenuous activities involved with diving and it will improve your body's respiratory system. This will lead to a reduction in air consumption and will improve the overall dive time of your dives.
22. Lose a few extra pounds
I am a big guy, standing in at 6'6" tall. However, although I'm heavy, I wouldn't say I'm overweight. Perhaps a few pound lost may not go a miss, but I'm presently working on this.
I'm not able to change my height, but I can control what I put in my mouth, how much exercise I do and how healthy I am.
I don't want this to be a weight loss site, but it's worth mentioning health and body weight, as both of these will impact your air consumption.
The bigger your body, the more energy it needs to sustain itself. The more energy needed to sustain your body, the more air it will consume.
This is one of the reasons for writing this article in the first place actually. Not because I am unfit or over weight, but because I am bigger than average scuba diver. On the whole I tend to consume air about the same as most average sized divers, but I have to work at this more than they do,due to the volume of my body.
I don't know how much extra oxygen my body burns compared to the average person, but whatever it is, it will be more. The average person weighs around 196 pounds. I'm 27% larger than that, but I have the same size dive tank as they do.
Funnily enough, if you do the maths, and add 27% to a 12 litre (80 Cu Ft) cylinder, you arrive at a 15 litre (100 Cu Ft) size of dive tank. So to be able to dive on a smaller tank and stay down for the same time proves my tips work!
Conclusion to tip 22 on conserving air when scuba diving - Size does matter when scuba diving. The bigger you are, the more oxygen your body consumes and therefore the more air you'll breathe. So unless you are able to consume less air by mastering air conservation tips, you will need to resort to diving with more air on your back.
23. Trim your kit
Each piece of kit you carry will increase your weight and change your buoyancy, but also potentially affect how streamlined you are in the water.
Always review what kit you take, as carrying extra pounds or kilos will affect your buoyancy and the amount of air you use.
In tip 15 about streamlining ourselves to help swim through water, where we have extra (perhaps unnecessary kit), this could interfere with how streamlined we are.
Conclusion for tip 23 on conserving air - Review the kit you take on the dive, as each extra pound or kilo you take will affect how much air you consume. Cut the weight and improve your air consumption.
24. Use a bigger dive tank - Use a 15 litre (100 Cubic Foot) cylinder - Dive time extending tip
Whilst this tip is not actually about conserving air, having a larger dive tank can be used by scuba divers who are struggling with their air consumption. This is a worthwhile tip to know, particularly when you're finding it difficult to master air consumption techniques.
This tip is about how you can extend your dive time, until such time as you've managed to perfect some of these tips and techniques to conserve air when scuba diving. Most beginner divers struggle with air consumption at the start of scuba diving, so to have access to every tip possible is great.
I didn't have the Internet when I first learnt to scuba dive, so I want to share as much of my wisdom and experience as I can with those that are new to scuba (or those looking to learn more), who are keen to learn and enjoy this fabulous sport.
Some of the techniques involved with conserving air on a scuba dive take time to perfect. For example learning buoyancy control is probably one of the harder ones to master.
In the mean time you want to be diving and learning to do these better, but at the same time enjoy nice long dives.
A larger dive tank will extend your dive time for you. A 15 litre (100 cubic foot cylinder) dive tank, instead of the more common 12 litre (80 cubic foot cylinder) dive tank, holds more air.
Therefore, with more air to consume, your dive time will automatically be extended. So using a 15 litre (100 Cu Ft) dive tank is a great way to extend your dive time, either permanently, or in the short term, whilst you perfect the art of conserving your air when scuba diving!
Important extra considerations when using a 15 litre (100 cubic foot) dive tank
However, there are a couple of considerations to review when using larger diving cylinders.
Larger dive tanks are heavier. Which means when you're kitting up, you will be heavier and a bit more cumbersome before entering the water. So be careful with the added weight, especially on a dive boat, and especially in choppier conditions. Watch out for your fellow divers too, as you don't want to be bashing into them!
It's not always easy to get 15 litre (100 Cu Ft) dive tanks on scuba diving boats. On all the dive boats in the Red Sea I've dived with, they've all had 15 litre (100 Cu Ft) cylinders. But in all the times I've dived in the Caribbean, most dive operators don't seem to use or have them.
With the larger dive tank, you'll also need to adjust your buoyancy. You'll be heavier when you first jump in, but more negatively buoyant in comparison on your ascent, when the cylinder is close to empty.
Conclusion to tip 24 regarding extending the dive time of scuba dive - Changing your dive tank for a larger one (i.e. 12 litre (80 Cu FT) to 15 litre (100 Cu Ft) will increase the amount of air you have and therefore extend your dive time. This is particularly useful when you're learning to dive and improving your air consumption techniques, but also for larger scuba divers too.
25. Use a twin-set - Dive time extending tip
As with the previous tip, this one isn't about air consumption as such, but more about having more air if you're struggling with your air consumption. As with adopting a larger tank, if you add an extra dive tank on your back, you double the amount of air you have to breath.
Using a twin-set of dive cylinders does tend to be used more for deeper diving, as the deeper you dive, the more air you consume. However, even if you're not going extremely deep, having a twin set of dive tanks will help.
As with the previous tip on using a 15 litre (100 Cu Ft) dive tank instead of the standard 12 litre (80 Cu Ft) dive tank, there are weight and buoyancy issues to consider. The weight of two 12 litre (80 Cu Ft) dive cylinders on your back is heavy. I used this setup when I was doing deeper dives around the coast of the UK (40-50 metres (131-164 foot) dives), as you consume much more air at that kind of depth.
The additional consideration of twin-set-cylinders is that it does require the addition of more scuba equipment. There's a special piece of kit which binds the two cylinders together. Also, with a twin-set you will need to buy an additional regulator set to attach to the second dive tank.
Conclusion to tip 25 on increasing your dive time - Double your dive tank air capacity by upgrading to twin-set dive tanks. With twice the air capacity your dive time will be extended. This is not recommended for beginner divers, but is a good idea for larger scuba divers.
26. Sex plays a role in scuba diver air consumption
This is not so much of an air consumption tip, but more of an observation and dive-buddy pairing tip.
There's a difference, and sometimes a huge difference, between the amount of air that men consume when scuba diving, vs the amount of air that women consume when they scuba dive.
There was a lady I loved to dive with when I was in the Red Sea. One of the reasons I loved to dive with her, she was great at spotting the wild life and we used to have so much fun diving together. There were many a time when my mask would fill with water through laughing so much! As I write this I realise how much I miss those dives with her.
When it comes to conserving air on a dive, think about respective scuba buddy air consumption rates
Anyway, the reason why this tip is important in the context of conserving air when scuba diving, is in diver pairing for dive buddies.
I would often joke with this lady, by saying that I'm sure she never actually breathed. The only way I could get anywhere close to staying down as long as her, was to either use my twin-set tanks or to dive with a 15 litre (100 Cu Ft) dive tank.
Even then, I'd return to the surface with the 50 BAR (500 PSI) recommended reserve, but she'd return with over 100 BAR (1,450 PSI) left in her 12 litre (80 Cu Ft) dive tank. And I was diving on a 15 litre (100 Cu Ft) cylinder!
So always consider who you're paired with on a dive. Of course if you're a couple and you want to dive together no matter what the difference in air consumption, then no problem. But if you're a woman diver and you get pair with a man, you will more often than not return to the surface sooner than you'd hoped, with more air left in your dive tank that he has.
This isn't such a problem if you're diving in a group and the dive master allows you to remain with the rest of the group, after sending your male buddy to the surface.
However, if as a female diver you dive in the Red Sea in buddy pairs in the way that I described above, your dive time may be curtailed when you dive with male divers.
Conclusion to tip tip 26 - Consider the difference between the rate of air consumption between males and females when choosing a buddy to dive with. Women tend to be more efficient with their air consumption underwater.
27. Using your buddy's alternative air source (Tip comes with a warning) - Dive time extending tip
WARNING: This tip or technique is not main stream and should only be done in certain circumstances. I would not recommend doing this if you're a beginner diver or if you are not diving with someone familiar to you. Only ever do this when you both have sufficient air to continue the dive on your own air supply. Plus be extra vigilant with the donors air supply and check their gauge regularly.
Going back to the time that I dived with the lady in the Red Sea, and as we were very familiar with each other as dive buddies and both very experienced, we would air share for periods of the dive. Well actually, I would air-share from her (not the other way around) and pinch some of her air!
I'd do this using her alternative air source or her octopus regulator. As it happened her alternative air source had an extended hose. This meant we could swim side by side quite easily with me using her air.
I wouldn't recommend this approach to beginners scuba divers or to buddy pairs that are not familiar with each other. You need to be totally confident in the water and have complete confidence in your dive buddy.
Extra safety tips if you consider using your buddy's alternative air supply
A few extra points regarding this tip about extending your dive time. You must be extra careful that you don't deplete the air in the dive cylinder of the dive buddy who is being 'used' as the host. The host or donor diver needs to be extra vigilant about their air consumption, as two divers are now consuming the air from the one dive tank.
If you are thinking about using this technique, consider buying an extra long hose for your octopus or alternative air source. Also, if you are diving in a group and with a dive centre, speak with the diver master beforehand about whether they are comfortable with you doing this. As most divers would assume that the one with the alternative air source in their mouth has a problem and has run out of air.
The dive master may or may not be happy, as this is not usually accepted to be done. However, they may be okay with it, but at least if they know before the dive, they'll not get concerned when they see the two of your breathing from the same diving cylinder.
Do not use this technique to extend your dive if your air tank is nearly empty. Only do this towards the beginning of the dive when you both have sufficient air to both return to the surface safely. You must be in a position that you can switch back to your own regulator and be able to continue the dive safely.
The added benefit of this exercise is that it provides practice for air sharing using an alternative air source. This is an exercise practiced in safety drills for rescuing a diver who's run out of air or who has a regulator that's stopped working.
Conclusion for tip 27 on extending dive time - Sharing your buddy's air by using their alternative air supply will extend your dive. This tip only works where there's a significant difference between two buddies air consumption. Please heed the above warning on this tip.
28. Consider a rebreather - Dive time extending tip
The concept of a rebreather works differently to a normal open air system. The way in which it works allows for a much longer dive time.
There are many pros and cons to a rebreather, which is cost, maintenance and potential danger in using them. Many improvements have been made on the design of rebreathers and it's not something I've personally used.
Conclusion to tip 28 on extending dive time when scuba diving - Consider investing in a rebreather to extend your dive time significantly. However, you still have the other constraints to contend with when you dive. For example, you will still have to consider depth and decompression.
What happens if you hold your breath while scuba diving?
Holding your breath while scuba diving is extremely dangerous. It's so dangerous that by doing so could actually lead to death in the worst case.
The main principle to understand is air expansion underwater versus the water pressure changes at the depth of water, which is explained using Boyles Law.
The easiest way to understand how dangerous holding your breath underwater while scuba diving can be, is to look at the pressure change between the surface and 10 metres (33 feet) down.
The water pressure at 10 metres (33 feet) is twice what it is at the surface. So conversely, at the surface (i.e. atmospheric pressure) the pressure is half what it is at 10 metres (33 feet).
If you fill a sealed container with air that holds five litres (1.09985 gallons) at 10 metres (33 feet) and brought this to the surface, the air would expand to 10 litres (2.19969 gallons). If the container was made of a non-expanding type material, the likelihood is that the container would explode with the pressure build up inside.
Now imagine this container we're talking about as your lungs. The average lung capacity is around 4-6 litres (0.879877- 1.31982 gallons). However, if someone were to inhale completely at 10 metres (33 feet). Then swim to the surface whilst holding their breath, and assuming this is an average person with a 5 litre (10.9985 gallon) lung capacity, the air inside the lungs would double.
The results of this would be catastrophic for your body. This would lead to problems such as a pneumothorax, a lung-over-expansion and/or an air embolism. All of which are not good problems to have.
What is the purpose of skip breathing?
Skip breathing is the method of holding your breath each time you inhale. The understanding behind skip breathing is that by breathing like this, the lungs will be more efficient at extracting oxygen from the air in your lungs. Skip breathing was originally thought to extend air time of an air cylinder, but there's no evidence to support this theory.
The research shows that by using the skip-breathing method, there will be a build up of carbon dioxide in the blood stream, which in turn will lead to an increased heart rate and respiration. The result of this will actually shorten your air time, rather than increase it.
As a word of warning, skip breathing is not recommended for scuba divers. In fact, I would positively advise against doing it. Because not only is there no evidence that it works (in fact the evidence is to the contrary), this could be dangerous for you to do.
I hope you enjoyed this article about tips to conserve air when scuba diving…
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