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How deep can you go?

Ever since people have been able to scuba dive, the quest to dive deeper has always been a fascination, with stranger fish to see, deeper shipwrecks to explore and discovering hidden places that no one has ever set eyes on before. But how deep can we go and what are the limitations?

The deep wreck, El Carbonero at 38m

There are many reasons people learn to Scuba Dive, exploring a new world, the excitement of adventure, learning a new skill, traveling the world and meeting new people are some of the most common. But one of the questions new divers are always keen to know the answer to is “how deep can I go?”.

Of course, this is a very important question when diving, but also its important to understand why we can dive to the depths we do. It would be amazing to be able to put the dive equipment on and sink to bottom of the sea, have a swim around and then come back to the surface, but sadly for us humans we are limited to laws of physics and have to apply these to our diving! These very laws are what dictate how deep and also how long we can spend underwater.

Deeper dives require multiple tanks

When you learn to Dive on the Open Water diver course you will learn in some detail why we can dive to the depth we do, what the limiting factors are, and how we can stick to these limits in a safe way. You will also learn that the maximum depth for a newly qualified Open Water diver is 18 metres. Now that doesn’t sound particularly deep when we consider that the deepest ocean is over 10,000 metres deep and the Titanic is at a depth of 3,800 metres! But rest assured that 18 metres is quite deep enough and when we also consider that that most of the oceans marine life lives in these upper sunlight zones we know we will always have something interesting to see when we dive!

If you want to dive a bit deeper you can take the Advanced Open Water Diver course which qualifies you to dive to 30 metres, here you find the light is slightly less and the marine life changes a little bit too, with the potential to see larger animals and deep water creatures! However, there is a trade-off to get here, as you go deeper the time you can spend here is dramatically reduced meaning less time to explore these new depths.

This trade-off or compromise is one of the reasons Scuba Divers are fascinated by the deep. We can’t spend long there, so we have to come back again and again to enjoy the delights of the deep and explore more each time.

There are other reasons our depth and time is limited, some of those include the amount of air we need to breathe and how much we can carry with us. The deeper we go, the more we need to take with us, so eventually we reach a point where we can’t carry enough. Also, there is the physics catching up with us again, the deeper we go the more decompression time we need during our accent (stopping periodically on the way back to the surface) to allow excess gas bubbles in our body to escape. The longer we stay and the deeper we go, the more decompression we need to do. Of course, we need to take the breathing gas for this part of the dive too, meaning more tanks to carry!

Decompression spent hanging on the line

With the Deep diver Speciality, you can extend your dive depth to 40 metres, you can only stay for a few minutes at this depth before you exceed your No-decompression time, but with limited time the excitement is amplified.

If you want to extend your depth and times further than this then you need to become a Technical Diver. These are the recreational diving elite and can dive to depths greater than 100 metres. By breathing a mixture of gases (Nitrox or Trimix), not just air, and by using a variety of diving technology including rebreathers, these greater depths can be reached and explored. The Advanced Nitrox and Decompression diver course is the first step towards reaching these depths, with a depth limit of 45 metres. A very high level of fundamental dive skills are needed to start these courses enabling you to learn new diving techniques, equipment set up and crucial dive planning and team work procedures.

There are other reasons that time and depths are limited, for example the Narcotic effect of the gasses we breath and how increased water pressure affects us and key safety aspects of deeper water. These are all things that you will learn about on the courses you can take, and with more training, knowledge and experience you will be able to dive deeper.

We don’t need to dive to these extreme depths to see wonderful things, the light zone is the most colourful and diverse but its fascinating to know that it is possible, and it’s a journey we can make if we want to dedicate the time and effort to learn.

So how deep can we go?

As long as you have the training, equipment and knowledge to do it safely, you can get all the way to the bottom!

Ed Smith is a TDI, PADI & PSAI Technical and recreational diving instructor with over 25 years of experience in the water. The views expressed in these blog posts are personal opinions based on many years of diving experience and teaching, however they may differ from other instructors or professionals. These blog posts are for information only and nothing should replace proper, professional training.

Dive safe.


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