Diver Down - A Runaway Dive

She knew if she let go, she would pop to the surface, 100 feet above her, with possibly life threatening results. But, she did not know how to solve the problem. As she tried to signal for assistance, her grip on the rail began to slip.

Lessons for Life - Dive Accidents, Close Calls & How You Can Avoid Them

By Mike Ange

Each Diver Down case presented on Seaduction.com is based on a true case that has been and thoroughly investigated using both official sources and through interviews with participants and witnesses. Names and some minor details have been changed to protect victims and their families.

A Runaway Dive

Sarah clung to the wreck’s side railing for dear life. She was battling a current and now her BC was, inexplicably, continuously inflating. She knew if she let go, she would pop to the surface, 100 feet above her, with possibly life threatening results. But, she did not know how to solve the problem. As she tried to signal for assistance, her grip on the rail began to slip.

The Diver

Sarah was an active diver in her late thirties who was enrolled in an advanced diving program to improve her skills and understanding of the sport. She was in reasonably good health with average to slightly-below-average fitness and she had logged around 50 dives in the several years that she had been certified. Most of her experiences were in the warm tropical waters of Florida or the Caribbean.

The Dive

Sarah and her husband/dive buddy were enrolled in an advanced training program that included deep diver training. They had been diving in South Florida for several days when they departed the dock for a dive on a deep wreck just offshore. Sea conditions were very good with a mild wind out of the southwest and gentle two- to three-foot swells. They arrived on the site without incident and moored to the wreck in what seemed to be a very slight surface current. The divers and their instructor suited up and entered the water to begin their descent in 86 degree water with very good visibility. As the divers descended the current picked up significantly. In fact, between 50 feet and their planned depth of 100 feet, the current was running at speeds of up to 1 knot.

The Incident

As the divers reached the bottom, they let go of the mooring line and began swimming forward along the ship’s deck, somewhat sheltered from the main thrust of the current. As the divers made their way forward, Sarah reached for her power inflator to add a short burst of air to her BC and achieve neutral buoyancy. Unfortunately, her inflator stuck in the open position and continued to add air after she released the button. She swam forward for several more feet before realizing that she was battling to stay down. Recognizing that she was too positive, Sarah attempted to dump the air from her BC, but was unsuccessful. Fortunately, she was close to the superstructure of the wreck and was able to grab onto the railing to keep herself from rocketing to the surface.

Her BC was nearly full now, with almost 50 pounds of positive buoyancy, and staying down required her to keep both hands on the wreck. Fighting the current on descent had left her winded and now the struggle with her BC was seriously taxing her physical endurance. Worse, she could not signal that she was having a problem because letting go of the wreck with either hand, she send her shooting to the surface.[private_Supporting]

The Intervention

When Sarah’s instructor noticed her erratic behavior, he swam over to investigate what was happening. Sarah felt the instructor grab her gear and knowing that she was in good hands, let go with one hand, nearly wrenching herself out of the instructor’s grip. Realizing the problem, the instructor was able to push Sarah underneath a platform on the wreck while he disconnected the inflator hose so that the BC would stop filling with air. They were then able to deflate the BC and get the dive under control preventing what could have been a runaway ascent, possibly decompression sickness or worse an embolism.

Analysis

Just before the incident, Sarah had her BC serviced at a local dive center. Unfortunately, BC inflators are often overlooked in routine preventive maintenance. It seems that many divers and even some shops do not consider the inflator mechanism to be the vital piece of safety equipment that it is. As a result, inflator problems, ranging from leaks, failure to activate or sticking in the open position, are all too common. Inflator failures of this type can deplete a diver’s gas supply very quickly, leave him with the inability to achieve positive buoyancy or force him rapidly to the surface.

When Sarah realized that her valve was stuck in the open position, she attempted to deflate her BC by lifting the corrugated hose and depressing the deflate button, but this technique did not vent air fast enough to overcome the stuck inflator. She was fortunate enough to have a solid structure to grab onto to prevent an uncontrolled ascent, but having done so, she could not let go of the structure to disconnect her inflator hose. Soon, the BC was fully inflated and venting air from its overpressure relief valve.

Sarah’s BC inflator hose was also equipped with a pull dump; a device consisting of a stainless steel cable that passes through the corrugated hose and activates the shoulder dump valve. Normally used to vent air from the BC when a diver is in a head-up position, the pull dump can also be used as a safety mechanism to stop a runaway inflator. Unless the diver is turned completely upside down and standing on his head, the “remote dump” is positioned so that it will effectively prevent a BC from filling with air. When the pull dump is open, the air from the inflator simply travels up the corrugated inflation hose and exits through the valve, never entering the BC bladder. Had Sarah recognized this, she might have regained control of her buoyancy by pulling down on the inflator with one hand and disconnecting the inflator with the other.

As a general preventive, have your BC inflator serviced annually. This includes, at a minimum, a thorough inspection, cleaning and lubricating of the interior mechanism. Although rare, it may be necessary to replace internal o-rings or valve components. Be sure to clean your inflator mechanism after every dive by flushing it with clean fresh water.  Divers should also make it a point to activate and release the inflator mechanism a few times as a part of their pre-dive gear assembly. It is clear that Sarah took her inflator to a qualified source for servicing just prior to her dive, but it is not clear whether she actually tested the inflator on the boat before the dive.

The reason that this was an incident and not an accident is that Sarah maintained a cool head. Grabbing the wreck prevented a runaway ascent and gave her instructor time to respond effectively.

Lessons for Life

• BCs are a vital part of the diver’s life support equipment and must be treated as such. Be sure your BC is serviced annually.


• Inspect and test your inflator by activating it several times before every dive.


• Thoroughly clean your inflator after every dive trip to keep it functioning properly.


• Learn how your equipment operates and what safeguards can be used to deal with unexpected problems during the dive.


• Do something. When the unexpected happens, many divers do nothing making themselves a simple victim of fate. A calm head and a rational response will generally reduce the risk in a situation.