Deep Sea Diving : Useful information..


There’s something exciting and mysterious about exploring deeper dive sites. While scuba diving. It may be the draw of exploring what few have seen at first hand. Discovering the marine life that is down there or exploring a wreck. Whatever the draw of deep diving is for you. We will take you through some points you will need to consider & be aware of. Along with some interesting facts.

How to get started

Well there is a little bit more to it than a normal scuba dive. Firstly you should ensure your first deep dive. Should be under the supervision of a dive instructor. You will be able to achieve this during your advanced open water dive course. You will be trained to dive to a depth of up to 100Ft (30 meters). Most dive centers will provide you with an option to enroll in a deeper dive specialty course. Wherein you will be trained to dive as deep as 140 feet (40 meters)

What is considered Deep Diving

In effect deep diving is anything deeper than 60ft (20 meters). But a technical dive is a dive deeper than 200ft (60 meters). Most recreational diving has a maximum depth of 130ft (40 meters).
If you have ever dived at a reef edge and looked down over the edge of that vertical wall. Then wondered what will it take to get down there and explore further? Well here are some details you may find helpful.

Deep diving

Deep diving or underwater diving to a depth beyond what is considered the norm. Accepted by the associated community. In most cases this is a prescribed limit established with a level of certification or training. Which may depend on whether the dive is recreational, technical or even commercial.
Deep diving can mean something else in the commercial diving field. For instance early experiment carried out by Comex S.A. (Compagnie maritime d’expertises). Using hydrox & trimix attained greater depths than any recreational technical diving. One example was an open sea dive to 1644ft (501 meters). That was in 1977.
Divers who dive this deep will need to breathe special gas mixture. Because they are exposed to very high ambient pressure. (more than 50 times atmospheric pressure).
An atmospheric diving suit allows very deep dives of up to 2000 ft (610 meters). These suits are capable of withstanding the pressure. Permitting the diver to remain at normal atmospheric pressure. This eliminates the problems associated with breathing high pressure gases.

Tips & rules for a Safe Deep Dive


  • Plan your dive. Always establish your maximum depth & bottom time.
  • Always perform the pre-dive safety check before diving.
  • Regularly monitor your depth & pressure gauge. Make sure that you have plenty of air in your tank for a safe ascent.


  • Don’t plan your dive so that it exceeds the no decompression limits of the dive table.
  • Never dive alone & always have an experienced buddy with you.
  • Never go beyond your planned depth nor exceed your bottom time.

Risks in Deep Diving

Deep diving is a relatively safe activity as long as you follow all the rules & procedures. Yet, it is important that you are aware of the inherent risk associated with diving at greater depths.

The bends

Also known as decompression sickness. As you breathe in air which is composed of oxygen, nitrogen & other gases. Your body uses the oxygen up but nitrogen is eventually released over time since our body does not need it.
So when pressure suddenly drops when you carry out a rapid ascent. Nitrogen gas inside your body expands & develops into bubbles. These bubbles are usually trapped in the joints causing severe pain. A diver with decompression sickness. Will be treated using hyperbaric oxygen therapy inside a recompression chamber.

Nitrogen narcosis

With nitrogen narcosis. You will experience a narcotic effect when you accumulate too much nitrogen. The first symptoms are usually tingling of the fingers along with dizziness & disorientation. It also affects your sight by experiencing  tunnel vision. Which makes reading gauges & instruments difficult. The deeper you go, the worse the effect of nitrogen narcosis will be.

Rapid air consumption

As you go deeper, due to increasing pressure, the air you breathe will become denser. So you will consume more air while you dive deep. In comparison to when you dive at a more shallow depth. So it is very important to constantly monitor your pressure gauge. As the deeper you go the quicker you consume it.
A good idea is to bring an additional small cylinder or what is called a (pony bottle). You can also stage a decompression tank at the safety stop line.

Equipment adaptations for deeper diving

The equipment you will use for deep diving does depend on both the depth & the type of diving. Scuba is limited to equipment that can be carried by the diver. The dive team can also deploy equipment as well. Surface supplied diving equipment can be more extensive. Much of it stays above water where it is operated by the support team.

  • Scuba divers carry larger volumes of breathing gas. To compensate for the increased gas consumption and decompression stops.
  • Rebreathers manage gas much more efficiently than open circuit scuba. But are inherently more complex than open circuit scuba.
  • A diving shot. Which is a decompression trapeze or a decompression buoy. This can help divers control their ascent. So they return to the surface at a position which can be monitored by their surface support team at the end of a dive.
  • Decompression can be accelerated by using specially blended breathing gas mixtures. Containing lower proportions of inert gas.
  • In-water decompression can be minimized by using dry bells and decompression chambers.
  • Hot-water suits can prevent hypothermia. Due to the high heat loss when using helium based breathing gases.
  • Diving bells and lockout submersibles expose the diver to the direct underwater environment for less time. They provide a relatively safe shelter that does not require decompression,. With a dry environment where the diver can rest. Then take refreshment, and if necessary, receive first aid in an emergency.
  • Breathing gas reclaim systems reduce the cost of using helium based breathing gases. Along with recovering and recycling exhaled surface supplied gas. analogous to rebreathers for scuba diving.
  • The most radical equipment adaptation for deep diving. Is to isolate the diver from the direct pressure of the environment. Using armored atmospheric diving suits. That allow diving to depths beyond those currently possible at ambient pressure. These rigid, exoskeleton suits are sealed against water. They withstand external pressure while providing life support to the diver. This can be up to several hours. At an internal pressure of approximately normal surface atmospheric pressure.
  • This avoids the problems of inert gas narcosis. Decompression sickness, barotrauma, oxygen toxicity, high work of breathing. But at the cost of reduced mobility and dexterity. Logistical problems due to the bulk and mass of the suits, and high equipment costs.

Worlds Deep Diving record

While connecting an underwater pipeline. A team of commercial divers reached a depth of 1752 ft (534 meters). They used a specially mixed breathing gas for this project in 1988. Off the coast of the Mediterranean sea.
There has been a scuba dive record as well. This deep scuba dive was recorded at 1090.45 ft (332.5 meters). This was  achieved by an Egyptian diver Ahmed Abel Gabir in 2014. This dive is in the Guinness world record for mankind’s deepest dive.
The worlds deepest wreck dive at Yolanda wreck in Egypt was performed at 676ft (205 meters). By Leigh Cunningham & Mark Andrews.

Ultra-deep diving

Amongst technical divers. There are divers who take part in ultra deep diving on scube below 660ft (200 meters). This practice requires high levels of training, experience, fitness & surface support. Not to say also with a great deal of discipline.
Only 35 people are known to have ever dived below a depth of 790ft ( 240 meters). On a self contained breathing apparatus. Yet  the holy grail of deep scuba diving was a staggering 980ft (300 meters). Which was first achieved by John Bennett in 2001 & has only ever been achieved seven times since. You have to be made of some serious stuff to carry out dives like this!
The difficulties involved in ultra deep diving are numerous. Although commercial & military divers often operate at those depths or even deeper. They are almost always supplied by the surface. All of the complexities of ultra deep diving are magnified. By the requirement of the diver to carry or provide for their own gas underwater.
These can lead to rapid descents & bounce dives! Unsurprisingly, this has led to  high mortality rates amongst those who practice ultra deep diving.

Animal that can deep dive

As divers, we spend a lot of time thinking about depth. How deep can we go before we experience nitrogen narcosis? Or exceed no-decompression limits? How deep before the oxygen in our dive cylinder becomes toxic? As a community, we’re always testing the boundaries imposed on us by depth. But several remarkable marine species have adapted to reach much greater depths. With comparatively little effort. Here are a few of the deepest diving animals. All air-breathing birds or mammals, for whom extreme diving is a way of life.


The deepest diving of all seabirds, the emperor penguin feeds primarily on fish. However, their diet also includes deep-dwelling squid and other cephalopods. Records show that they’ve dived down to 1,755 feet (535 m) in pursuit of prey. The emperor penguin is perfectly adapted to survive these deep dives. Its wings are flatter and stiffer than those of other birds. Enabling extra propulsion. Its bones are solid, rather than air-filled, to reduce the risk of barotrauma. These penguins can also slow their heart rate to just 15 to 20 beats per minute while diving. In order to minimize oxygen use. To counter the icy temperatures of the Antarctic waters. Emperor penguins have the highest feather density of any bird species. They have a layer of sub-dermal fat that measures over an inch thick.


The leatherback turtle is unique among turtles. In that its carapace is made of toughened skin. Hence the name leatherback, rather than a bony shell. This adaptation gives the turtle added flexibility under pressure. It signals the leatherback’s status as one of the deepest diving animals. Scientists have recorded leatherbacks at depths of 4,200 feet (1,280 m). Following the daily daylight migration of the jellyfish they eat. In order to cope with the incredible pressure at such depths. These turtles have developed several other important adaptations. These include collapsible lungs, which reducing the risk of the bends. They have the ability to slow their heart rate to conserve oxygen. Along with pulmonary sphincter. That circulates blood away from the lungs while they are collapsed. The ability to regulate body temperature so that it remains constant. Regardless of the surrounding water temperature.


Reaching lengths of up to 66 feet (20 m), sperm whales are the world’s largest toothed predators. They sustain their huge size by diving to incredible depths. In search of their preferred prey, squid. Scientists have recorded sperm whales at depths of up 7,380 feet (2,250 meters). They can remain submerged for as long as 90 minutes. They have also evolved to survive under extreme pressure. One of their most important physiological features is a flexible ribcage. This allows for the lung to collapse.  The reduced absorption of nitrogen. Like elephant seals, their blood carries extra myoglobin and red blood cells. They are able to direct their bloodstream away from non-essential organs. While diving in order to make the most of depleted oxygen levels. In the pitch black of the abyss, sperm whales find their prey through echolocation.


Both species of elephant seal can hold their breath for more than 100 minutes. This makes their dives as remarkable for their length as they are for depth. Male elephant seals often dive for more than 60 minutes at a time. With a depth record for this species is an incredible 7,835 feet (2,388 m). Like the leatherback turtle and the emperor penguin. Food is the incentive for the seal’s astonishing dives. They prey  on deep-dwelling species including skates, rays, squid and octopus. Elephant seals are a deep-diving success. Because their bodies hold a large volume of blood. This allows them to store more oxygen. They also have increased levels of myoglobin. Allowing them to store oxygen in their muscles. A larger percentage of oxygen-carrying red blood cells. Along with exceptionally thick blubber to protect them from the cold at depth.


There is a lot to think about when deep diving, the lure of the unknown is certainly appealing. However even the bigger thrill seekers out there need to install some discipline. When approaching deep diving as there is a lot to consider & just as much to potentially go wrong. However if you follow the procedures & guides laid out. It is a fantastic & safe activity that can produce an experience like no other. So all the training & dedication is absolutely worth it.

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