by Dr. Thomas Powell:
Imagine you are 15 feet underwater in a zero visibility environment, alone, and searching through the unknown for the remains of another human being. You do not know the layout of the underwater environment, nor are you aware of any potential obstructions or tangle hazards. These are the moments that public safety divers deal with around the world every day. The public safety realm is one in which safety is critical and redundancy is the norm. Moments like the one described above show why equipment and action redundancies are designed, planned, and implemented.
Communication is often the thing that can calm the nerves of a public safety diver. A new diver settling into black water for the first time may be filled with anxiety and breathe so hard he or she burns through air too fast to perform a legitimate search pattern. Tenders often discover that one of their primary roles is to calm the diver on the end of their tethers. A friendly and supportive voice can help center a diver and bring him or her back to reality and back on track. When voice communications fail, the ability to help a diver remain calm may falter. For this reason, both divers and tenders need to understand and be able to perform communication activities using various redundant methods.
Voice communication is the most simple and modern version of diver communication. Essentially, a diver can use a voice activated or push-to-talk system to speak openly to a base station, receiver, or tender. Surface personnel can also communicate back to the diver. In the case of wireless communications, or multiple divers with hardwired communications fed into the same surface system, the divers may also have the ability to communicate between one another. Voice communication systems allow divers to discuss plans, actions, and events as they arise. Surface personnel can be apprised of what is taking place underwater and provide direction as needed using real-time explanations. The problem with voice communication systems is that sometimes electronic systems fail underwater.
Line signals are another form of communication. They are a signaling method used among different types of public safety organizations to signal actions and well-being. Because so many organizations use line signals, they become an action set that can easily be transitioned into a diving environment. Line pulls are based upon the idea that the tether between a tender and diver remains taut. A certain sequence of pulls from any direction is pre-planned to have a certain meaning. Using these pull sequences, the diver and tender can remain in communication when voice-based systems fail. To remain competent in the use of line signals, they must be practiced by divers and tenders. Divers must work search patterns and practice keeping the tether line tight. Simultaneously, the diver must practice relying on the tender for directional cues. Without directional cues, the diver may perform an improper search pattern if he or she does not have the ability to see. If these actions are not practiced, both divers and tenders will forget line-pull sequences and perform poorly during critical situations.
The availability of voice communication systems often make dive teams lazy in the sense that they rely too much on the electronic systems and do not practice redundant communication methods. The other factor that must be remembered is that divers are rarely tethered together barring situations such as ice dives. This reality suggests that line pull signals are not often available for divers to communicate between one-another unless a diver-to-diver tether is put into place. For this reason, hand signals are essential as a redundant form of underwater communication between divers.
Finally, hand signals are one of the most basic forms of underwater communication. All divers know them and practice them throughout all forms of scuba training. Hand signals work between divers underwater when all other forms of communication fail. The catch is that divers choosing to dive together must work to understand what certain hand signals mean. Different divers may choose to use imperial or metric gauges (different measurements to signal), or to express information using different methods. To prevent confusion or misunderstanding, divers must verbally and visually walk through hand signals on the surface before entering the water.
Public safety divers must also practice tactile hand signals. In the public safety world, black or brown water environments are common. Environments such as these often eliminate visibility and the potential use of common diver-to-diver hand signals. Tactile hand signals are based on the idea of one diver touching another diver in a certain manner that has pre-determined meaning. When divers cannot see, tactile hand signals allow those divers to communicate through basic touch. Again, these types of hand signals must be practiced to ensure understanding and basic use prior to diving.
Communication is critical for public safety divers. Divers must know they are supported by a surface team that understands the situation, and surface personnel must know how best to protect and support divers under the water. When one method of communication fails, the failure may be based on an incident endangering a diver. For this reason, redundancies are essential when communication is involved. Line and hand signals allow a diver to communicate with other divers or a tender when electronic communication systems fail. To remain safe and competent, divers must practice and train in the use of redundant communication methods. Practice will ensure muscle memory and clear mental recall of communication methods. Safety is critical in the public safety world, and with practice and training public safety dive teams can set themselves up for success.
– Dr. Thomas Powell
Owner/Instructor Trainer – Air Hogs Scuba, Garner, NC