What are common depths for beginner scuba divers and how deep can a beginner go?
It’s important as a beginner scuba diver to become confident underwater, before you go too deep. One of the most important things to remember as you learn to become a scuba diver is the scuba diving environment is to be respected. When scuba diving you are not in your natural breathing environment.
The common depths for beginner scuba divers is between 9-20 metres (30-67 feet) whilst learning to dive. At the next stage of scuba certification, the most common depths are between 18-35 metres (59-115 feet). Once certified, the depth limit for most recreational scuba diving is 40 metres (131 feet). But with experience and more training this depth can be exceeded.
A dive is considered deep at depths greater than 18-20 metres (60-67 feet). The deeper the dive the more impact it has on you. This is due to increases in pressure as you descend. The deeper you dive the greater the risk of decompression sickness or the bends, the possibility of nitrogen narcosis and even the risk of oxygen toxicity.
Why is depth an important consideration for scuba divers?
Firstly, before I explain what are the common depths for beginner scuba divers, I want to explain why depth is important.
There are a few reasons why depth is important for scuba divers. But I first need to explain the concept of depth and pressure underwater.
Understanding the concepts of pressure and depth underwater
Most people understand that water is more dense than air. For example one litre (1.76 pints) of air vs one litre of water, most people understand that the one litre of water would be much heavier.
The deeper you go underwater, the more pressure that is exerted on your body. For example the weight of air at sea level is referred to as 'one atmosphere.' This pressure at sea level is exerted though gravity, and as you ascend through the atmosphere, the pressure decreases.
If you've ever been up in an aeroplane or climbed a large hill or mountain, and as a result your ears have 'popped,' this is due to the change in air pressure. The reverse happens when you land or come back down the hill or mountain.
As you descend in a aircraft, you'll feel pressure on your ears, until you equalise the air pressure. This is because the pressure of the air when the plane is on the ground is higher than it is when you're flying.
Pressure increases as you descend underwater
Using the same concept as the flight one above, but underwater instead. As you descend underwater the pressure increases. If you've ever dived down in a swimming pool to the deep end, you will probably have felt the same ear-pressure sensation as you would when you fly. This is due to the increase in water pressure on your ear drums in the same way.
The deeper you go, the higher the pressure. For example, if you were to descend to 10 metres (33 feet), the pressure at this depth would be the equivalent to that of two atmospheres or double what it is at sea level. If you descend further to 20 metres (66 feet), the pressure of the water is equivalent to three atmospheres. ?Or three times the pressure at sea level. And so on.
Here's a quick summary of the pressure of water down to 50 metres (164 feet) deep:
- 10 metres (33 feet) - Two Atmospheres or 2-bar. Where 1-bar = 1 atmosphere.
- 20 metres (66 feet) - Three Atmospheres or 3-bar.
- 30 metres (100 feet) - Four Atmospheres or 4-bar.
- 40 metres (131 feet) - Five Atmospheres or 5-bar.
- 50 metres (164 feet) - Six Atmospheres or 6-bar.
Why is the pressure of the water important?
Now that I've explained how the pressure increases as you go deeper, let's take a look at why the pressure is so important to scuba divers.
Scuba divers breath air in the normal way underwater. Except that the air is delivered from a tank on their back. For the majority of scuba divers, and in particular beginner scuba divers, the air that is breathed is normal atmospheric air. Or in other words it's the same air as you are breathing now whilst reading this article. Unless of course, you're reading underwater!
However, the only difference is that the air has been compressed. But the composition is still the same, where roughly 79% is nitrogen and 21% is oxygen.
Reason no. 1 why depth and water pressure matters to scuba divers - Oxygen toxicity
The first reason why scuba divers need to be aware of how deep they dive is due to the fact that at depth oxygen in the normal percentages of atmospheric air becomes toxic to humans at depth.
The depth at which oxygen toxicity occurs is after around 60 metres (197 feet). It may not happen immediately and it does also depend on circumstances, but any depth beyond 60 metres (197 feet), scuba divers face an increasing risk of oxygen toxicity
Having explained this, beginner scuba divers will not be going anywhere near this depth to begin with. But also, scuba divers that dive to depths of 50+ metres (164+ feet) are classed as highly advanced and technical divers. These types of divers will then be using a different air mixture to that of atmospheric air. Thereby reducing the percentage of oxygen and avoiding the risk of oxygen toxicity.
Reason no. 2 why depth and water pressure matters to scuba divers - Boyle's Law
The other concept to understand as a beginner scuba diver is whereby the deeper you dive, the quicker you use up your air supply. This is about understanding the concept of Boyle's Law.
Boyle's Law explains how the volume of a gas, which in this case is air, changes with the surrounding pressure. So to put this law in simple terms: If the pressure surrounding a gas is increased; the volume of the gas will get smaller. Conversely, if the pressure surrounding a gas is decreased, the volume of the gas will become greater.
This means that at depth at let's say at 10 metres (33 feet), for the lungs to inflate to the same size as they do at the surface, where the pressure is twice that of atmospheric pressure, because the volume of air has halved in size you'll have to breath twice the amount of air. That means you'll end up breathing twice as much air at 10 metres as you do at the surface.
Don't worry too much about this concept at this stage of your leaning to scuba dive. It took me a while to understand. But the most important thing to remember is that the deeper you go the faster you'll consume your air.
Other factors affected by Boyle's Law
There are other factors relating to diving that are affect by Boyle's Law. These include not holding your breath as a scuba diver and how the deeper you go the heavier you become.
You must not hold your breath as a scuba diver, as the air in your lungs is affected by pressure using the concept of Boyle's Law.
If you were to hold your breath at say 10 metres (33 feet) and return to the surface, without breathing out, the air in your lungs would double in size. This is because by applying the principles of Boyle's Law the water pressure at the surface is half that of what it is at 10 metres. That means the pressure applied to the air in your lungs has halved. If you were to hold your breath in this way, your lungs would simply burst.
The other factor I mentioned that affects scuba divers as they descend is they effectively become heavier, the deeper they go. This is because all the air spaces get squeezed, and as they do this results in lower buoyancy for the scuba diver. Scuba divers have to compensate for this reduced buoyancy. This is done by pumping additional air into their buoyancy control device, or BCD.
Reason no. 3 why depth and water pressure matters to scuba divers - The bends or decompression sickness
One of the most known reasons why scuba divers need to be concerned about depth, is the affect it has on the amount of nitrogen that gets dissolved in their bodies as they dive.
The oxygen content of air during the dive is used in metabolism, as it is on the surface. But the nitrogen is not used by the body and is usually breathed out again. But the nitrogen at pressure is dissolved into the bodily tissues, it's dissolved into the blood stream and so on.
The deeper you go, the greater the pressure, the more nitrogen is dissolved. Also, the deeper you go, the faster the nitrogen is absorbed by your body too.
When you reverse the pressure by coming back to the surface, if you were to return too quickly, the nitrogen would escape too fast. Fast escaping nitrogen would result in the formation of tiny bubbles. It's these bubbles that are the danger to you. Depending on where they form, how large they are and how many are formed, will depend on your fate.
This process is referred to as decompression. Where the nitrogen is decompressing out from your body. If you were to ascend too quickly, and without the proper safety stops, you would simply 'fizz-up.' This 'fizzing-up' is referred to as either decompression sickness or the bends.
Reason no. 4 why depth and water pressure matters to scuba divers - Nitrogen narcosis
The final reason why depth matters to a scuba diver is also related to nitrogen. At around 30 metres (66 feet), the amount of nitrogen that's absorbed into the body can begin to have strange affects on you.
This strange effect is referred to as nitrogen narcosis. Not all scuba divers are affected by nitrogen narcosis. Plus different divers are affected in different ways too. Some scuba divers can feel drunk and behave in strange and funny ways. Whilst others can become extremely depressed and have fearful thoughts.
The reason for explaining the above four reasons, before coming onto the original question, which was 'what are common depths for beginner scuba divers,' is to put why depth is so important into context.
How deep do beginner scuba divers go and what are common depths?
Now that I've explained why depth is important to scuba diving, lets take a look at 'what are common depths for beginner scuba divers.'
Beginner scuba divers commonly start off their training either in a swimming pool or in very shallow, but in a sheltered body of water. This could be a lake or a sheltered beach.
If the initial training is done in a swimming pool, then this is obviously very shallow and not deep at all. But if the beginner scuba divers are being trained in the sea, this could be anything up to about 9 metres (30 feet). But the area must be very sheltered, where there are no tides or currents.
During the training stages of learning to become a certified scuba diver, you will normally train to a depth of between 18-20 metres (59-66 feet).
Whether the maximum training depth is 18 metres vs 20 metres will depend on the scuba diving school. For example, PADI have a limit of 18 metres, whereas BSAC have a limit of 20 metres.
PADI Open Water Diver
If you decide to train with PADI, which is the largest scuba diving organisation world-wide, the first stage is to become an 'Open Water Diver.'
This training course includes both theory exams and underwater training. The water training usually begins in a swimming pool and progresses to open water.
How deep can you go with open water certification?
At the Open Water Diver level of certification with PADI, you are advised to not dive any deeper than 18 metres (59 feet). It's recommended to build up your experience at this level by diving as many dives as you can. Before moving on to the next diver certification level.
With BSAC this stage of certification is referred to as Ocean Diver, but an Ocean Diver can Dive to 20 metres (67 feet) when certified.
For PADI, the next stage in the training is Advanced Open Water Diver or AOWD. The recommended depth for an AOWD is 30 metres (100 feet).
My recommendation is to do at least 20 dives before progressing beyond the Open Water or Ocean Diver stage
I’d recommend that you complete at least 20 dives at 18 metres as an Open Water Diver or an Ocean Diver, before you progress to the next stage. It's not a race and remember that scuba diving can be dangerous if the water is not respected.
Things can go wrong. If you don't have the right level of experience when it does go badly wrong, you could put yourself and your buddy at risk.
PADI only require you to complete 4 open water dives at the Open Water Diver stage. Plus a further 5 dives on the Advanced Open Water Diver training. This makes a total of 9 dives.
For me this is too few, when you can go to 30 metres (100 feet) at the next certification level of AOWD.
My advise is to be careful and be safe. Don't rush it. For example, SSI requires 24 logged dives before you are able to progress to their equivalent Advanced Open Water Diver stage.
For me using the word 'Advanced' in the name of the next PADI level is misleading. I think it should be intermediate or similar instead.
For example, an Advanced Diver at BSAC will need to have completed many more dives. This would probably be recommended at over 100 dives. Plus the training involved in becoming an Advanced Diver at BSAC is much great. Before this level you need to qualified first as a Sport Diver, then as a Dive Leader first.
BSAC Ocean Diver Course
The equivalent BSAC course to the PADI Open Water Diver is the Ocean Diver Course. As already mentioned, once certified as a BSAC Ocean Diver, you would be able to dive to 20 metres (67 feet).
As with PADI, I then recommend that if you decide to train with BSAC instead of with PADI, that you do a minimum of 20 dives before you beginning the next level of training.
The second stage of training under BSAC is to become a Sports Diver. Once a Sports Diver, you'd be able to dive to 35 metres (115 feet). But like I've already advised, I don't think that an inexperienced scuba diver should be diving any deeper that 18-20 metres. At least until they've completed 20 dives or more at or around that depth.
How many dives do you need for open water certification?
To become a certified scuba diver with PADI it takes four open water dives to obtain your Open Water Diver certification.
The pool session or sheltered or confined water session, with pool-like conditions, are not specified in terms of number of dives with PADI. Instead PADI specify what needs to be learned, and subject to how quickly this is learnt, will govern how many dives are carried out in the sheltered water.
The same is true of BSAC. For you to become a certified Ocean Diver you need to complete at least 4 open water dives. With BSAC you are also required to carry out at least five pool sessions or sheltered water dives too.
In these initial 5 lessons you are taught similar skills to those taught by PADI.
How long does it take to become a certified scuba diver?
The time it takes to become a certified scuba diver is partly dependent on you. If you're a confident swimmer and if you're able to do the mask clearing task quickly and easily, then it may take between 2-3 days.
The theory lessons and exam will be down to you and how long you take to learn. If you're a quick learner and take the exam and pass, this could easily be done in a couple of days too. Perhaps even shorter, especially if you're a quick reader.
You can either choose to run the theory lessons alongside of the practical water-based lessons and dives. Or you can choose to do this beforehand.
Many choose to learn the theory first, especially if they are learning to scuba dive on holiday.
Nobody really wants to be stuck learning theory on a holiday or doing an exam when they are away on vacation.
How deep is the average scuba dive?
Most recreational scuba divers don't dive much deeper than 40-50 metres (131-164 feet), depending on the organisation they trained with and their level of diver certification.
But in terms of how deep the average scuba dive is, I'd say this would be somewhere between 15 and 25 metres (49-82 metres).
Always remember that diving deep or deeper is not necessarily better. Often times there's more to see in the shallower depths.
For example, I recently wrote an article on Bahamas tiger shark diving, which included details about Tiger Beach. Tiger Beach, which is a renowned scuba dive for seeing tiger sharks, is only at around 6-10 metres (20-33 feet). For me that's the perfect dive, but it's not deep.
One of my favourite dives in Barbados is at a depth of just 10 metres (33 feet). Some of the best diving in the UK in my opinion is in the Farne Islands with seals, most of these dives are at around 14-15 metres (46-49 feet).
Deep may be different, but not necessarily better.
But having said that, there are equally some excellent scuba dives at depth too. There are many ship wrecks at depth. If you decide that diving on wrecks is your thing, you may find that you have to dive to a certain depth for your chosen wreck.
So how deep do divers usually go, is very much dependent on the diver and what they like to dive for. For example, in my earlier scuba diving days, I used to do a lot of deep dives to see wrecks around the UK coast. Some of these wrecks were sitting in up to 50 metres (164 feet) of water. But now I prefer not to dive much deeper than about 30 metres (100 feet).
How deep can you dive before being crushed?
A question people sometimes ask is 'how deep can a human go underwater before being crushed?' This depends on whether or not you are diving freely as a scuba diver or in a submarine.
In a submarine, man has been able to dive to a depth of 10,930 metres (35,858 feet) below the surface of the ocean. This is as deep as the oceans goes on planet earth.
But also, with the right equipment like a Newtsuit, developed by Canadian scuba diver Phil Nuytten, divers are able to dive extremely deep. The Newtsuit functions like a submarine. Thus allowing the diver to work at normal atmospheric pressure, even at depths of 300 metres (1,000 feet).
The deepest scuba diver
A scuba diver made a record-breaking scuba dive in the Red Sea off the coast of Dahab, Egypt.
The dive was done by Ahmed Gabr, who plunged about 332 metres (1,090 feet). This is the deepest scuba dive ever and at that depth he wasn't crushed.
I hope you enjoyed this article about what are common depths for beginner scuba divers
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Have fun and be safe!