第1页
An Insanely Dangerous Activity Agnes Milowka was one of the foremost cave divers in the world. Female, photogenic, and experienced, she had gained international recognition for her exploratory work in many underground caverns around the world. In early 2011, she entered Tank Cave, near Mount Gambier, a seven-kilometre maze of narrow tunnels - yet ones she had explored many times before. Deep inside, she parted company from her
第2页
dive buddy to explore a tight passageway through which only one person could pass. What happened next will never be exactly known, but the nature of the cave suggests that she became disoriented during a 'silt-out'. Unable to manoeuvre quickly, with visibility almost zero, she could not find her way back, and her air ran out.Thinking of these last moments is disturbing, but illustrates the obvious dangers of cave diving. When
第3页
anything goes wrong, divers cannot swim vertically to the surface, but must instead navigate the entire way back. The dive is immediately abandoned, but even with the full team at hand, the return is complicated by narrow tunnels, often lined with sand, mud, or clay, all of which can be easily disturbed - the dreaded 'silt-out' - where, in a few seconds, the diver is in a panic-inducing soup of sediment, virtually blind. Arti
第4页
ficial light is swallowed in the pitch blackness, and there always needs to be sufficient breathing gas. In short, cave diving seems an insanely dangerous activity.Yet the cave-diving community disputes this, arguing that their sport is actually safer than normal open-sea recreational diving. This is due to the much greater degrees of experience and training, and the special equipment used. Most fatalities that have occurred a
第5页
re a result of breaking accepted protocols, where improperly trained and inadequately equipped divers take on caves well beyond their capabilities. Cave divers maintain that, if the rules and guidelines are followed, their sport becomes acceptably safe. In the rare cases where deaths have happened while following these, there have typically been unusual circumstances, such as unexpected currents or rock falls.So, what are thos
第6页
e protocols? There are five major ones, all decided upon after extensive accident analysis (the breaking down of accident reports to find their most common causes). Firstly, a cave diver should be trained and experienced. This is done in carefully documented components, each dealing with increasingly complex facets of cave diving, and accompanied with relevant, dive time before progression onwards is allowed. The next rule is
第7页
the same as with all diving, whether open-sea or cave. It concerns the maximum depths and the decompression stops needed to allow the release of dissolved nitrogen from the blood. This is all carefully calculated in a dive plan before entering the water, and every diver must strictly adhere to this.The next two protocols each concern a vital piece of equipment. Firstly, a guide rope is an absolute necessity. This is secured at
第8页
the cave entrance, and fed into the cave by the lead diver. Sufficient tension is always maintained, and often the rope is tied up at regular lengths within the cave interior to ensure this. In the event of a silt-out, all divers, in theory, can find this rope, using it to guide their way back to the cave entrance. Equally crucial are the lights. A diver without lights is effectively marooned, unable to go anywhere. Each dive
第9页
r is therefore required to have three independent sources: a primary, and two backups.
