Scuba diving is a rewarding and adventurous sport that allows us to explore the underwater world. How else would we be able to see sunken ships, underwater caves, beautiful marine life, and so much more without scuba diving?
Many scuba divers, especially the newbies, are concerned or curious about just how deep they can dive or are allowed to dive. It’s not rocket science that you can’t dive infinitely. After all, your scuba tank doesn’t have an infinite amount of gas. But how deep you can dive isn’t entirely dependent on the amount of gas in your tank.
In this article, I’ll be comprehensively answering the question on the minds of many scuba divers – ‘How deep can you scuba dive?’
Short answer: How deep you can dive depends on your training and level of experience. Recreational divers can dive to a maximum depth of 40 meters/130 feet, technical divers can go up to 100 meters/ 330 feet.
To understand the limits of your diving, you have to understand diving physiology and diving physics.
Understanding the Limits of Diving
Diving Physiology
The human body didn’t evolve to be underwater and the high pressure underwater has an effect on the systems in the body, especially the circulatory and renal systems. The fluid balance of the body is also affected. When you are underwater, more blood is sent to your brain and heart and this necessitates the need to keep your core warm while you dive. Wearing appropriate scuba gear will help with this.
Despite the fact that the physiology of your body is affected during a dive, it doesn’t directly affect how deep you can dive. Other factors, which will be discussed below, come into play.
Diving Physics
Diving physics directly affects how deep you can dive and the most important limiting factor affecting how deep you can go underwater is nitrogen consumption. As you may already know, pressure increases the farther you go underwater – there’s an increase in pressure by one atmosphere for every 33 feet underwater.
This increment in hydrostatic pressure means the partial pressures of the gases in your tank also increase. And the effect of this is that some of the gases are stored in the tissues and they remain so until you start to make your ascent.
Pressure decreases as you start to ascend and the gases in the tissues get the chance to escape. But there’s a limit to how much nitrogen the body can absorb until nitrogen necrosis sets in which is similar to a state of drunkenness and can lead to divers making poor or wrong decisions. There’s also an increased risk of decompression sickness the deeper you dive.
Nitrogen can be replaced with oxygen to decrease nitrogen absorption but this also increases the risks of oxygen toxicity as the body may absorb more oxygen than it needs. This is why different gas blends for scuba diving have maximum operating depth, limiting how deep a diver can go.
Air Consumption
Your personal air consumption affects how deep you can dive. The deeper you go underwater, the faster you’ll need to breathe and this increases the rate at which you consume air.
Different divers will have different air consumptions due to different lung capacities. But with more experience and better overall fitness, you will be able to better manage your air consumption.
Level of Training / Experience
Your level of training and experience will ultimately determine how deep you can dive because each diving course comes with a maximum depth limit. To reach greater depth, you’ll have to take advanced courses to learn more about diving at deeper depths.
A basic open water diver has a limit of 18 meters / 60 feet. If you want to go a little deeper, you’ll have to take the advanced open water course that teaches you how to make it beyond 60 feet. You can be taught how to reach the maximum depth limit for recreational divers which is 40 metres/130 feet.
Technical diving will teach you how to dive deeper than 40 metres/130 feet. By taking a technical diving course, you’ll learn how about decompression procedures, how to use specialized gas mixtures, wreck penetration, cave and cavern diving, as well as how to use a rebreather, doubles and/or sidemount to extend your bottom time.
What Happens to Your Body if You Dive Too Deep?
Water / Pressure Effect
As I mentioned earlier, the increasing water pressure underwater has an effect on your body’s physiology. And if you dive deeper than you’ve been trained for, the increasing water pressure can compress your lungs and start to cut off your air take. Eventually, your heart rate will diminish and your blood vessels may burst.
Nitrogen Narcosis
Compressed gas builds up in your body the deeper you dive. Nitrogen, especially, has an intoxicating effect on the body and this can cause you to lose control of your senses. Unless you are able to regain control of your senses and return to the surface, you can get killed.
Nitrogen narcosis is significant around 100 feet as the high pressures at this depth cause the scuba diver to inhale more compressed air, and consequently, more compressed nitrogen. The 100 feet mark is generally beyond the limit of recreational divers and this means most recreational divers are at a lower risk of nitrogen narcotics.
But still, recreational divers are taught to make a 3-minute safety stop when returning to the surface to allow absorbed gases to escape. Better to be safe than sorry. If you start feeling drowsy at any point when scuba diving, start to make your way to the surface.
How Deep Can Divers Go with Scuba Gear?
You now know that there are different limits for the recreational diver and the commercial diver. However, it’s possible for a diver to go as deep as 1000 feet with the right training and equipment. Commercial divers with specialized equipment such as atmospheric suits are capable of reaching 2000 feet.
What Gas Mixes Do You Need to Dive Really Deep?
Very deep dives require special gas mixes and this is one of the things you’ll be learning when you take a technical diving course. The need for special gas mixes is to make breathing comfortable and counteract the effects of nitrogen narcotics. For this purpose, nitrogen is usually replaced with helium or hydrogen.
Traditional scuba diving air mix, which is compressed air containing 21% oxygen and 79% nitrogen, is only suitable for dives not exceeding 40 meters (130 feet). Using this gas beyond this limit significantly increases nitrogen narcosis.
While some technical divers may use pure oxygen, it is rarely used because of the risk of oxygen toxicity. Below are some common gas blends used for diving.
Nitrox
Nitrox mixes consist of 22-40% oxygen and it’s more common to see blends having 32-36% oxygen. The main benefit of nitrox is its lower nitrogen composition which lowers the risk of nitrogen narcosis. Also, the decompression limit of the diver is increased. Note that nitrox is meant for shallow diving and should be used by recreational divers. Care must also be taken to use a dive computer that can deal with nitrox.
Trimix
Trimix consists of a mixture of oxygen, nitrogen, and helium. The purpose of the helium is to reduce the amount of nitrogen in the blend. You already know the reason for this. Trimix blends may contain 21% oxygen, 44% nitrogen and 35% helium (some contain 45% helium).
What is Saturation Diving?
Saturation diving is one of the most advanced forms of diving that revolves around the premise that the pressure of the gas dissolved in your blood and tissues is equivalent to the gas in your lungs. The reason for this is to reduce decompression time and make it irrespective of the time of the diving.
Large-scale underwater repairs or construction are done by saturation divers. These divers reside in a high-pressure ship or barge during the duration of their work and stay spend a few days out at sea. Here’s an interesting read about saturation diving.
Frequently Asked Questions
How Deep Can 10 or 11-Year-Olds Dive?
The maximum depth for a 10 or 11-year-old diver is 12 meters / 40 feet and they must dive with a certified adult diver.
How Deep Can a 12 to 14-Year-Old Dive?
A 12 to 14-year-old Jr. Open Water Diver can dive up to 18 meters / 60 feet. After getting a Jr. Advanced Open Water Diving Certification, he/she can go a little deeper and reach a depth of 21 meters / 70 feet. 12 to 14-year-olds must dive with a certified adult diver.
What’s the World Record for Deepest Dive?
As of today, the deepest scuba dive anyone has made from the surface is 332.35 meters/1090 feet and 4.5 inches. It was accomplished in 2014 by Egyptian diver Ahmed Gabr, in the Red sea, in Egypt. It broke the 2005 record of 318.25 m (1044 ft) held by Nuno Gomes – but some doubts have since appeared as to the validity of Gabr’s record.
Final Thoughts
As a recreational diver, it’s important to know your limits and stay within them. You don’t need to go super deep to enjoy the wonders and beauty of the underwater world. Commercial divers may go far deeper but their journey is far from a joy ride as their focus is on getting work done and the great depths may have a toll on them physically and mentally.
