by Steven M. Barsky
Surface-supplied diving gear is one of the safest types of diving systems available to the properly trained public safety diver. The benefits of a hard-wired communication system with an unlimited air supply cannot be denied. It’s simply hard to beat the proven reliability of this type of dive equipment, especially when you are diving deep, in contaminated water, or diving at night
The very first commercial diving job I went on I was assigned to the night shift, diving from a 250-foot long supply ship in the North Sea in 8-foot seas. It did not matter to the diving crew whether it was day or night; the diving went on around the clock. As the first diver climbed the ladder and kicked off his expensive Jet Fins, abandoning them to the sea so he could get out of the water, I realized just how serious professional diving is, and how danger is always present. Public safety diving is no less risky, but every opportunity must be taken to minimize risk. Admittedly, commercial divers sometimes accept risks that no right thinking public safety diver would take.
Probably the most difficult part of learning to dive with a surface-supplied diving system is coming to grips with the management of the diving hose, or “umbilical.” Whether you are diving in black water or night diving, knowing where your hose is at all times is fundamental to safe diving with an umbilical system. The corollary to this is that your umbilical must never go under any obstruction that would prevent a direct ascent to the surface; since as a surface-supplied diver, you are obligated to follow your hose back to its origin.
If you manage to take a turn around your descent line (down line) or go under an obstruction, like a wreck or a pipeline, in the event of an emergency, you will be prevented from making an unimpeded ascent. In these circumstances, especially in black water, it’s unlikely you will be able to sort out this situation if you are panicked. This is part of the reason it is so vital to always know where your umbilical is located. Prevention is key; always go over any obstruction you may encounter, and when ascending, always come up on the same side of the down line you made your descent on.
Most umbilicals used by public safety divers today are made with a thermoplastic hose that not only is highly chemical resistant but also floats readily. This combination of characteristics makes them ideal for surface-supplied diving and will help to prevent entanglement. While some people think the risk of entanglement might be higher with surface-supplied gear, this is simply not the case.
Of course, it’s always essential to wear a bailout bottle whenever you use a surface-supplied diving system and using one while diving at night or black water is vital to your safety. Use the largest bailout bottle you can comfortably carry. For dives deeper than 60 feet of seawater, the cylinder should be an 80 cubic foot bottle.
Surface-supplied night diving need not be more hazardous than diving during daylight hours. Like any working dive, the job must be approached with the right training, the right equipment, and sufficient practice to help ensure the diver’s safety. Trying to make a rescue or recovery without adequate training and practice is always a recipe for disaster.
About the author:
Steven M. Barsky is a TDI/SDI instructor and has authored diving textbooks for SDI and other training agencies. He is the author of Diving in High-Risk Environments and Investigating Recreational and Commercial Diving Accidents. He also produced the DVD video, Choosing and Using Full-Face Masks. You can reach Steve through his web site at www.marinemkt.com.
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