Dive enthusiasts need to be proficient in their skills before indulging in deep diving. As compared to recreational diving, deep diving entails a descent up to depths of 60 and 130 ft. The risks in this type of activity are much greater than conventional diving, thus the need to exercise greater caution.
The lure of the deep is one of the most fascinating aspects of recreational diving. For the new diver, the deep zone represents a multitude of questions. What’s down there? What does it feel like? Will I be able to do it? Will I run out of air? What will I encounter? The thought of deep diving is both exciting and intimidating.
While 90 percent of all the fish, coral and marine life can be found between the surface and 60 feet, there are some valid reasons for going deeper. Yet, diving deeper than 60 feet should not be undertaken lightly. To be a responsible deep diver requires knowledge, experience, understanding and skill.
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Deep Diving Defined
Deep diving is defined by most scuba training agencies as descending to depths between 60 and 130 feet. This definition can be further broken down into three distinct zones: 1) Surface to 60 feet – scuba training and basic diving; 2) From 60 to 100 feet – recommended zone for normal recreational diving; and 3) From 100 to 130 feet – limited to graduates of advanced open water and specialty deep diver courses.
The basic prerequisite for engaging in deep diving training is that you must have completed a minimum of 20 open water scuba dives after becoming open water certified. In other words, you must have gained sufficient diving experience to feel comfortable at depth (to 60 feet) and be able to demonstrate proficiency in all of the basic scuba skills. For some people, that may require 20 dives while others may take longer – 30 or 40 dives. The important point to remember is that you should never undertake a dive deeper than your personal comfort zone.
For most scuba training agencies (PADI, SSI, NAUI) an advanced open water course includes at least one deep dive to 100 feet. Yet, this is only the beginning of deep diving training rather than the completion. The next obvious step is to enroll in a deep diving specialty course.
Why Deep Dive?
Deep diving is done for a specific purpose – to see something, explore something or encounter something that one would not find at lesser depths.
Deep diving is not done just for the thrill of it. Bottom time is too precious for that. Deep diving requires making a sacrifice – you must be willing to give up significant dive time (bottom time) in order to experience something special. Here are a few examples.
Wall diving: The exploration of vertical drop-offs is perhaps the single most compelling reason for deep diving. Wall diving has become immensely popular in the warm water regions of such areas as The Bahamas, Caribbean, Red Sea and the Pacific. At deeper depths of 80 to 120 feet, divers encounter huge sponge formations and gigantic gorgonian fans in spectacular colors. The beauty and splendor of these marine life formations are awesome. Wall diving is a major activity in places such as the Cayman Islands, Belize, Palau and Fiji.
Wreck diving: Shipwreck exploration is the second most popular reason for deep diving. Many of the best wrecks (especially in warm water) lie at depths ranging from 90 to 130 feet – a quiet zone where these ships are undisturbed by the battering forces of storms or hurricanes.
A good example of intact shipwrecks are the twin wrecks of the Duane and Bibb that lie off Key Largo in the Florida Keys. Both vessels are ex-Coast Guard Cutters measuring 327 feet in length. The Duane sits upright in 118 feet of water while the Bibb lies on her starboard side in 130 feet. Perched on the edge of the Gulf Stream, these wrecks offer crystal clear visibility and 80oF water temperature.
Other intact vessels that attract divers to the 100 foot zone include Theo’s Wreck off Freeport, Grand Bahama; the Stavronikita off Barbados; the RMS Rhone in the British Virgin Islands; and a dozen WW II Japanese shipwrecks in Truk Lagoon.
Pinnacle diving: A lesser known activity that is growing in popularity is pinnacle diving. Pinnacles are church spire-like formations of rock or coral that rise from the depths to within accessible scuba limits.
Good examples of this type of diving are the many pinnacles off Saba Island in the eastern Caribbean. Dive sites such as Outer Limits, Third Encounter and Shark Shoals rise from the deep blue to within 90 feet of the surface. The formations are loaded with colorful marine life.
Some coral pinnacles lie just off the main vertical drop-off of certain Caribbean islands. A good example is Three Sisters, which lie off the East End of Grand Cayman and Ghost Mountain, off the North Wall. Most of these formations rise from the deep to within 70 feet of the surface.
Seamount diving: Still another reason for deep diving is seamount diving, the exploration of offshore mountain tops that rise from the deep to within 90 or 100 feet of the surface. Seamounts such as El Bajo and Gorda Banks, both in the Sea of Cortez, attract an enormous amount of fish life. It is not uncommon to encounter giant schools of pelagic fish on these deep formations.
Marine life encounters: Many of today’s divers engage in deep diving for the specific purpose of possibly encountering or photographing pelagic fish not normally found in shallow water. A good example is the incredibly graceful Spotted Eagle Rays that cruise along the vertical face of Grand Cayman’s North Wall. These splendid creatures are often encountered at depths of 80 to 100 feet – sometimes swimming in a formation of four to six rays.
Other deep water inhabitants include the schools of Hammerhead Sharks that can be encountered off Cocos Island and on the seamounts of the Sea of Cortez. Deep diving at night in the waters of Australia is one way to encounter schools of Flashlight Fish. Visitors to New Caledonia make nighttime deep dives to find the elusive Chambered Nautilus.
There is one more benefit of deep diving that is certainly worth mentioning. By learning and practicing deep diving techniques, you will improve your skills at every diving level.
The Price Of Deep Diving
So far, we have discussed the benefits and rewards of deep diving. What about the down side? As with many things in life, deep diving has its price. You will have to make some sacrifices and overcome challenges in order to engage in this form of diving.
Shorter dive times: Deep diving involves significantly decreased bottom time limits – 60 to 80 percent shorter. Compare the no decompression time limits in our sidebar for 60 feet versus 130 feet and 50 feet versus 100 feet and you will quickly see the difference.
Increased nitrogen narcosis: While some people begin experiencing nitrogen narcosis at as little as 80 feet, the official Red Line Limit is 130 feet for recreational diving. Beyond this depth, the risk and effects of nitrogen narcosis increase rapidly and the results can be fatal. The worst effect of narcosis is sudden, unexpected blackout.
Increased risk of DCS: Deep diving increases the risk of decompression sickness. So does repetitive diving, especially over a period of several days. Don’t push the limits of the tables or your computer – use them conservatively. Researchers are finding that decompression sickness is not purely a mathematical formula based on the laws of physics. Residual nitrogen bubble nuclei can change the blood chemistry and set you up for a case of unexplainable bends.
Engaging in deep diving is a matter of personal choice. Should you decide to undertake this activity, you must do so with the knowledge that you may be increasing the risk of DCS.
Increased anxiety: During the first few deep dives, you may experience anxiety, stress, nervousness – all normal human reactions. Your thoughts may mull over a variety of dilemmas. The surface seems a long way away. What if my regulator stops working? What if I run out of air? What if I get separated from the others?
What About Going Deeper?
There is no law in the U.S. that prohibits you from descending beyond 130 feet. You may hear of divers going deeper. You may be invited to join others on a deeper dive. Let your conscience and knowledge be your guide.
Once you descend beyond 130 feet, you have left the realm of recreational diving. You are now engaged in an entirely different activity, described by many names: commercial diving, professional diving, technical diving and so on.
If you choose to enter this other world, first consider some of these aspects. The risk is much greater. Any life or accident insurance you have is invalid. You may be barred on many dive boats that strictly adhere to the 130 foot rule. You may not be welcome in some countries or islands where a recreational dive depth limit has been made law.
When it comes to deep diving, equipment selection is crucial. Buy equipment made by reputable manufacturers who are members of the Diving Equipment Manufacturers Association (DEMA). These companies manufacture their equipment to standards set forth by DEMA and the American National Standards Institute (ANSI) to ensure it functions as intended. If you travel, choosing gear from a dive equipment company with a world-wide network of dealers and distributors is a good idea – should you need emergency repairs or a replacement for something accidentally left behind, you have a better chance of finding a local shop to supply it.
Regulator: Your regulator must be in good working order – smooth breathing, no leaks, no stickiness. The best kind of regulator for deep diving is one with a balanced piston first stage that will maintain a consistent intermediate pressure. The second stage should be a high performance unit with servo-assist or adjustable valve so you can reduce breathing resistance to a minimum and maximize air flow. At depth, breathing becomes more of an effort. Some regulators have knobs that allow them to be adjusted by the user to provide greater air flow at depth. (This same knob allows them to be detuned on the surface to avoid freeflow.)
Extra second stage: In deep diving, it is essential that you carry an extra second stage, also known as an octopus. Make sure the extra second stage is in good working order and positioned in the “safety triangle” between your chin and two elbows – so it can be easily recognized by your dive buddy, should an out of air emergency occur.
Submersible pressure gauge: In deep diving, your air supply diminishes rapidly and you must have an accurate submersible pressure gauge that is easy to read at a glance. A luminous dial face with fluorescent markings is helpful, especially in the dim light of the depths.
Your SPG must also be in perfect working order. If it is leaking air (a slow trickle of bubbles) or shows signs of being flooded (water or droplets in the dial face), replace it before making the dive.
Power inflators eliminate the need for removing your second stage mouthpiece at depth in order to put air in your BC by means of an oral inflator. Removing your mouthpiece at 100 feet is the last thing you want to do.
Depth gauge: As with the pressure gauge, deep diving requires a highly accurate depth gauge with a dial face that is easy to read – especially at depth, where slight narcosis may make things fuzzy. A luminous dial face can be very helpful in the dimly lit world of the deep.
Dive timer: In deep diving, time is your most precious commodity. Your entire bottom time (at the deepest point) may be only four or five minutes. You will need a dive watch or other type of instrument that clearly displays elapsed time. You cannot afford any sort of confusion or ambiguity. Some manufacturers offer depth gauges that also keep track of and display dive times and surface intervals. And, of course, this an integral function of dive computers.
Electronic dive computer: The electronic dive computer has become the most welcomed innovation in the world of deep diving. This sophisticated instrument automatically tracks and displays such vital data as: maximum depth, current depth, elapsed dive time and remaining dive time for a no decompression dive.
The most important function of these instruments is to automatically calculate the no decompression limits for the dive profile – taking into consideration the multi-level aspect of the dive you are making. Such instruments guide you through an entire dive.
One of the most interesting innovations is that many of these computers now monitor your rate of ascent – displaying it graphically and setting off an audio alarm if you exceed the maximum rate of ascent. These instruments are incredible! Choose one that is easy for you to understand and read. Keep in mind there is less light at depth and you may be slightly narced.
Computer backup: If you plan to make your deep dives with a dive computer, you should have a backup system. While these computers are very reliable, there have been occasions when a battery goes dead or something is broken owing to a severe blow.
Many instructors recommend you carry a set of plastic dive tables in a BC pocket, along with an extra timing device/depth gauge, for emergency use.
BC with power inflator: The buoyancy compensator has become mandatory for most all forms of diving. There is an additional requirement for deep diving – the BC should be equipped with a power inflator (sometimes called a pressure inflator). This is connected to the regulator first stage by means of a low pressure hose and allows you to inflate the BC with the touch of a button.
Dive suit: Selecting a suit for your intended deep dive requires careful consideration. If you are diving in cold water, you will want a neoprene wetsuit of the appropriate thickness. The effects of cold tend to accelerate the onset of nitrogen narcosis, as well as becoming a contributing factor for DCS.
If you are diving in warm water, you may choose to wear a tropical dive suit made of nylon/Lycra or a 1/8 or 3mm neoprene wetsuit. Wetsuits are available in a variety of configurations, including full length jumpsuits, with short arms and/or legs and in farmer john pants with jackets. Wetsuits offer the greatest thermal and body protection.
Dive light: While not essential for open water deep diving, a small dive light comes in handy for reading your instruments at those dimly lit depths. You can carry it in the pocket of your BC where it will not be in the way or become entangled in your other equipment. A dive light will also help to reveal the brilliant colors of many deep water sponges and gorgonian fans.
If you intend to explore the interior of a deep wreck, you should carry a large dive light – as well as a small one for emergency backup.
Dive knife: In deep diving, a knife is considered emergency safety equipment. For example, wrecks attract fish and fish attract fishermen, thus monofilament line is always a potential problem when wreck diving. A sharp knife is a must.
Slate with pencil: While not mandatory, an underwater slate with a pencil serves as an excellent backup system for underwater communications. While hand signals are the primary method for communicating, there are some things that cannot be described with them.
Preparation for the deep dive is just as important as the dive itself. In some ways, it is more important because your preparation involves safety backups that may be required if something goes wrong.
Let us assume your deep dive is being made from an anchored boat – the normal setup for this type of diving. First, check to see there is an appropriate descent line. The anchorline will suffice, but a straight down descent line is preferable.
Next, make sure a full scuba tank with a well-functioning regulator is lowered over the side of the boat to a depth of 15 feet. This hang tank becomes your emergency air supply should you run low on air during safety decompression.
While you and your dive buddy are underwater, there should be an experienced crew member remaining aboard the boat to lend assistance in case of emergency. The boat should also carry emergency oxygen and first aid equipment. With everything in place, you can begin to set up for the dive. Make sure the tank you have selected is filled to maximum capacity – usually 3,000 psi for an aluminum tank.
Attach the BC and regulator to the tank and turn on the valve. Listen carefully for any sign of air leakage between the O-ring on the tank valve and your regulator. If you detect a leak, replace the O-ring with a new one or switch to another tank.
Once your regulator is connected, check your submersible pressure gauge to make sure it is functioning and not leaking air. Check both air sources by breathing a few cycles on both your primary second stage and your octopus. Next, switch on your dive computer(s) and check the displays to make sure everything is functioning correctly.
Once you are sure that your breathing equipment and instruments are functioning correctly, you can make a dive plan. The plan should be made as close to the time of the dive as possible so none of the details is forgotten.
Select a specific objective for the intended dive. It may be on a wall to a certain sponge formation or a visit to a certain part of a wreck or exploration of a specific coral crevice. Discuss the details of your intended dive with your partner – carefully noting depths and times. Allow yourself enough safety margin in case you are delayed during the course of your dive. Also, review the underwater hand signals you intend to use in communicating with your dive partner.
Have a backup plan in case you become separated from your buddy. The typical fall back plan for separation is to go back to the top of the wall or the anchorline or any other major reference point.
Finally, take your time in dressing for the dive. Rushing with your gear and hurrying to get into the water often lead to mistakes.
Diving The Plan
The key to safe and enjoyable deep diving is attention to detail and consistency. You need to develop a step by step routine you repeat dive after dive, until it becomes second nature to you.
Monitor your descent to ensure all instruments are working. Maintain eye contact with your dive buddy and stay alert for signs of problems (ear clearing difficulty, water in the mask, etc.).
Use the down line as a reference and a way of controlling your descent. The line will help you remain in position despite current conditions. It will also help you adjust buoyancy. Keep one hand on the line and the other on your BC inflator (in case you need a shot of air to compensate for wetsuit squeeze).
Make the first part of the dive the deepest part of the profile. Upon arriving at the deepest point, compare instrument readings – depth, tank pressure, time – with your dive buddy.
Swim with your dive buddy. Never stray more than 10 feet from his or her side. You need to be close to provide assistance – or to receive it. Check visual contact with your buddy every 60 seconds. Exchange hand signals frequently, both to provide assurance and check for narcosis. Be aware of your elapsed dive time and air consumption. Check your dive time and tank pressure every two minutes.
Make sure your buoyancy is neutral – be cautious about sinking or rising. Being too heavy or too light requires extra effort to stay in place and thus accelerates air consumption.
Be alert for subtle currents that may push you away from the boat or descent line. Make periodic visual checks of the bottom topography, selecting unusual coral formations as reference points. You may wish to use an underwater compass to track the direction of your swim.
Be aware of your remaining dive time. Depart from the deepest part of your dive profile with at least a five minute margin of safety. Start moving gradually up the reef or wall to lesser depths.
If you are using a dive computer that is equipped with audible alarms, be alert for a repeated beeping. It could be coming from either your or your partner’s computer. The audible alarm (beeping) means you have violated some portion of your dive profile. It could be one of several violations: exceeding your no decompression limit for a specific depth; exceeding the rate of ascent; or bypassing a mandatory decompression stop. Pressure integrated dive computers are equipped with additional audible alarms.
Begin your ascent from the reef or wreck with a minimum of 1,000 psi in your tank. Make a slow ascent using the descent line to control speed and buoyancy. Never exceed an ascent speed of 60 feet per minute but you can ascend slower. In fact, an ascent speed of 30 feet per minute is more desirable in shallow depths (60 feet and up).
Make a safety stop at 15 feet for 5 minutes. If you think you violated your dive profile by exceeding your no decompression limit or ascending too fast, double your safety stop – stay at 15 feet for 10 minutes. If you know you really blew it, triple your safety stop or stay at 15 feet as long as your air supply will allow.
Sticking close to your dive buddy is one of the key factors in safe deep diving. You must be in a position to maintain visual contact with your dive partner in order to detect early symptoms of nitrogen narcosis or deep diving anxiety.
These symptoms are often created by anxiety, stress or possibly the initial effects of nitrogen narcosis. If any of these symptoms are noted or recognized, begin a slow ascent to shallower depths.
The code of the responsible diver:
As a responsible diver I understand and assume the risks I may encounter while diving. Responsible diving begins with:
- Diving within the limits of my ability and training
- Evaluating the conditions before every dive and making sure they fit my personal capabilities
- Being familiar with and checking my equipment before and during every dive
- Knowing my buddy’s ability levels as well as my own
- Accepting the responsibility for my own safety on every dive
The following is a list of unusual symptoms that may indicate the onset of a problem:
1 Rapid heavy breathing when unnecessary
2 Jerky movements of hands, arms or head
3 Slowness to respond to hand signals
4 Wide-eyed panic appearance in facemask
5 Preoccupation with instrument displays
6 Jumpiness or sudden recoil from familiar objects
7 Uncontrolled rapid ascent