Skin divers need to practice emergency swimming ascents to reduce the risks involved in such a maneuver. Several important factors to remember in executing such ascents are discussed.
When you are out of air and ascend directly to the surface, that’s an emergency swimming ascent. Usually this occurs in a life-threatening situation, when there is an equipment malfunction, the diver is out of air, experiencing a medical abnormality or threatened by the environment. There is an immediate need to reach the surface.
A common reason for a diver to bolt toward the surface is running out of air, which is usually as senseless as running out of gas in a car. When it happens, the diver is warned when it becomes harder to breathe, then the tank seems empty. At this first warning, immediately stop what you are doing and start toward the surface. As you rise in the water column, the pressure is reduced, the remaining air in the tank expands and you may get a few additional breaths. In addition, the air in your lungs will expand on ascent, allowing you to continue exhaling. It is critical to continue a purposeful, steady exhale against all temptation to hold your breath and streak toward the surface.
An out of air emergency is only very rarely caused by regulator failure, which could lead to rapid depletion of the air supply. If you have a concern about this type of failure, consider installing a Y – slingshot style – valve on your tank. This has two orifices for attaching separate regulators accessing one air supply. If one regulator fails but there is still air in the tank, a diver may use the other regulator.
During an emergency swimming ascent, the diver ascends directly to the surface without voluntary safety stops or required decompression stops. Given the choice of drowning or getting the bends, choose the surface and air! This is one reason sport divers are encouraged to plan all dives as no decompression dives. It is not possible to perform an emergency swimming ascent and make decompression stops.
There are several choices you must make about your emergency ascent in an instant, including whether it will be independent (solo) or dependent (buddy assisted).
These can be the best choice in some circumstances. If you are in shallow water (less than 40 feet) or cannot make immediate contact with your buddy or have an extra/redundant source of compressed air, simply swimming to the surface on your own may be the prudent choice.
Redundant air systems are small, compressed air cylinders that divers carry in addition to their main scuba cylinders. Sometimes called pony bottles, these small cylinders have a separate regulator and are mounted next to your normal scuba tank. You have probably seen pictures of cave or wreck divers with these backup bottles. They vary in size from 15 to 40 cubic feet. While necessary pieces of equipment for a closed environment diver, a pony bottle adds substantial expense, maintenance, weight and underwater drag to a casual reef dive.
Smaller cylinders such as Spare Air offer one to two cubic feet of air. They have a regulator built into the valve and are carried in a holster. The diver pulls the unit out of the holster, places it in his/her mouth and holds it there while ascending. While they are easy and convenient to use, the tanks may not have enough air to allow a diver to ascend slowly from significant depths at a normal rate.
Buoyancy compensators may offer a source of emergency air. If you have inflated your BC with scuba tank air, the air is accessible through the oral inflator and breathable, although probably not germ-free. Most people do not clean the insides of their BCs well enough to be assured there is no mold or bacteria. In an emergency, given the choice of germ-laden air or no air, bacteria probably will not be your biggest concern.
To breathe air from a BC, first clear the water from the inflator hose. Blow into the inflator mouthpiece while in the face down position. Then, roll away from the inflator hose and onto your back. Look toward the surface, extending your arm overhead with the inflator in hand. Exhale into and inhale from the mouthpiece, while holding the valve open. Breathe continuously while you swim toward the surface at a normal slow rate of ascent.
Using your BC as a source of air takes practice. Use the technique first in confined water, before attempting practice in open water. If you roll in the wrong direction, your first breath will be water, not air.
Buoyant ascent is another option. While it does not provide any air to the diver, it may make movement toward the surface speedier. If you remove your weightbelt, drop heavy tools, game bags or retain the expanding air in your BC or drysuit while ascending, you will become more buoyant. Controlling your ascent rate can be difficult, however.
The deeper you are when initiating these steps, the smaller the changes in buoyancy. If you are wearing a one-quarter inch wetsuit and remove a lightly weighted belt at 100 feet, your buoyancy may not seem to change. You will need to begin swimming toward the surface and decreasing the compression of the wetsuit before you feel a positive buoyancy change. The closer you get to the surface, the more buoyant you will become.
As you feel your rate of ascent increasing, you will want to slow down. Arch your back and flare out in a spread eagle position to increase the drag on your body. Remember that expanding air may become available in your tank or BC as you near the surface. The flaring technique is important because your speed will increase as you near the surface. You may feel out of control but remember to focus on continuously exhaling.
Dependent ascents require the assistance of a buddy who is ready, willing and able to share air. How the buddy shares air is determined by available equipment, extra air, skill of the divers and the dive’s circumstances.
In the ’70s buddy breathing was performed with one regulator mouthpiece on a short hose, passed between two divers. It takes a lot of practice and composure to make this work smoothly. Hopefully, you learned one regulator buddy breathing in your scuba course and the experience made you a believer in octopus regulators. Old fashioned buddy breathing, sharing one mouthpiece, is difficult to do with an anxious diver, in moving water and/or for any length of time.
In the ’90s we have superior equipment available, which makes sharing air much more practical. Whether it is called an extra second stage or an octopus, the concept is the same. Each diver’s regulator has a primary and secondary mouthpiece. The diver uses one during the dive and has the second mouthpiece available should the buddy need it. The extra mouthpiece often has a longer hose so it can bend and reach the diver in need. If the hose is too short, the divers kick each other and are forced to assume body positions where they cannot maintain eye contact.
When one buddy signals a need to share air, the optimal situation is to:
1) Immediately offer and accept the extra mouthpiece
2) Establish breathing control
3) Calm down and assess the situation
4) Face each other for best eye contact and hold onto each other’s forearms to assure constant contact
5) Look toward the surface
6) Begin slowly kicking toward the surface
7) Adjust buoyancy as needed to maintain a slow, controlled rate of ascent
8) Breathe normally
9) Move toward the surface at a proper pace. Recognize that if one diver ran out of air, his/her buddy may also be nearly out of air so there is no time to waste.
Among different instructors and agencies there has been a long running discussion about which mouthpiece gets passed to the diver in need. Some say the diver with air keeps his/her own first stage and passes the extra second stage. Others say it is faster to hand the person in need the regulator out of your mouth, then the calmer donor diver finds his/her own extra second stage and begins using it. Divers in this situation have commented that the diver in need wants a regulator he or she sees is working and if you don’t offer it, it may be taken anyway. You and your buddy – for each dive – need to review which procedure you plan to use.
Regardless, it is critical you both know where and how the extra second stage is located and attached. The spare mouthpiece should be visible and accessible someplace in the chest area. Avoid putting the regulator in a BC pocket or underneath the BC, where it will be hidden. Secure the mouthpiece to your BC with a holder or clip so it is not dangling and crashing into the reef.
When you brief for a dive, show your buddy where your octopus is, point out if the hose is color coded and show how it is clipped to the BC. Depending upon your plan, make the hose that gets passed the longer of the two. Your buddy should know how to unclip your spare mouthpiece. If you dive with gloves, be sure you can operate the clip with gloved hands. You should be able to locate and unclip your own spare mouthpiece completely by touch. Shut your eyes after you gear up for a dive and see if you can locate and unclip your octopus by touch.
During the pre-dive briefing is also a good time to check your air. Is the valve turned all the way on and then one-quarter turn off? Sometimes new divers get confused and turn the air all the way on, then turn the handle back several turns so the air supply ends up nearly off.
Diver error is a frequent cause of out of air emergencies. A regulator fails occasionally but not often. It is usually a case of a diver getting engrossed in an activity and forgetting or ignoring gauges. It is silly to endanger yourself and your buddy in this way. Make it a practice to monitor your own gauges, as well as your buddy’s, several times throughout the dive. A good dive plan includes a turnaround psi number. For example, plan to swim along a reef using 800 pounds of air, then turn around and head back on 800 pounds of air, ready to exit the dive with 650 pounds of air for ascent and safety stops. Then, watch your air consumption and stick to the plan.
No matter what combination of redundant air equipment or shared air techniques you use, practice with your buddy. After being out of the water for a time, you will need sharing air practice to smoothly execute the skill.