Underwater magnetometers are old fashioned tools that have come into the new age of affordability and portability. J.W Fishers and other companies produce low cost but effective systems that can detect metal objects underwater and, sometimes, up to 20 inches beneath sediment or further. Advances in handheld units and underwater metal detectors have been readily accepted by teams and routinely deployed as standard equipment. They are cost effective and allow divers to perform sweeping searches while looking for smaller metallic objects like handguns, jewelry or shell casings.
Finally, surface supplied air delivery units have quickly become the standard for dive units. These systems are comprised of an approved oil-less air compressor and a series of in-line filters that scrub and clean the air. They create clean, breathable air at a pressure and flow rate capable of sustaining a diver at depth for extended periods of time. They also pump clean air to the diver's full face mask or helmet by means of a tether and umbilical system.
Umbilicals consist of at least three but sometimes four individual components: A hose that transports the compressed air to the diver; a safety line to connect the diver to the surface; hardwired communication lines for the divers' earphones and microphone; and a device called a pneumofathometer, which allows the surface to monitor a diver's depth at all times.
Adopting surface-supplied air into public safety diving requires advanced training and understanding of diving physics and physiology. But the system also allows for longer dive times, safer air quality, and also eliminates the gauges and loose hoses that can entangle and endanger divers. In the event of entrapment, a diver has the extended air supply while he slowly and safely frees himself.
Public safety divers vary drastically from their sport diving counterparts. As technology continues to advance, improvements in design, material selection and functionality are sure to come, and future offerings are sure to have a direct impact on the continued safety and capabilities of these dedicated individuals.
Michael S. Glenn teaches Forensic Sciences and Underwater Diving Operations at North Carolina Justice Academy. He welcomes comments at email@example.com.