Although never, ‘The Silent World’, the physical limitations of a water environment continue to pose problems for divers intent on communicating effectively with their companions, or with the surface.
While advances in surface-to-diver, diver-to-diver voice communications systems have had an enormous impact on occupational diving safety, the use of such devices by the recreational/technical diving community has met with limited success; not least because few recreational divers require such complex – or costly – communication systems; especially when there already exists a variety of time-honoured techniques that usually prove adequate to their needs.
Although able to be adapted to suit a variety of environmental conditions, the worth of each method is only as good as the diver’s understanding of the ‘language’ being used and – through practice – their proficiency in its use. In that regard the more ‘languages’ that a diver understands, the better equipped they will be to communicate their intentions effectively with others when the need arises.
Diving communications – whether between divers under-water, or between divers on the surface and the control position – fall under three broad headings: manual, visual and sound.
MANUAL
Line Signals
The widespread introduction of voice communication systems has, in many instances, made the use of line signals almost redundant. Often considered an anachronism that has little place in today’s high-tech world of diving – particularly by free-swimming divers engaged in scuba operations – a good knowledge of life-line signals should still be a part of every serious diver’s basic repertoire of skills.
For tethered divers line signals provide a back-up communications method should the primary system fail. Divers on scuba, particularly in reduced visibility, can communicate their intentions via the buddy-line or by tactile pressure, ie. hand squeezing. If using a surface marker buoy or safety float a surface observer can visually monitor the diver by the bobbing of the marker or, from a boat, transmit messages through the safety line to the diver below.
Whenever life- or safety lines are used there are a number of considerations to bear in mind. The line should be secured to the diver’s safety harness using a bowline knot. The inboard end of the line must be similarly secured, either to the vessel or surface marker buoy, and the line kept free of slack. (A good tender should be able to ‘feel’ the diver at all times without putting an undue strain on the line.)
Signals made with a line are of two types: The PULL – a long, steady and very distinct tug on the line, and the BELL – a short, sharp pull with the same timing and sequence as that of striking a ship’s bell (i.e. 5 bells = Ding-Ding: Ding-Ding; Ding)
Any communication via the line, either surface-diver, or diver-surface, must be acknowledged by returning the same signal. (Except for the emergency signal, a succession of pulls, which must be acted upon immediately.)
All of the signals are preceded by one pull on the line to attract attention and are then made once either the diver or the attendant has acknowledged with a return pull. When a signal is received it is repeated back to the sender to indicate that it has been properly interpreted. (Although it should be remembered that a working diver may not always be in a position to respond immediately, requiring the tender to wait a short while before again repeating the signal.)
The beauty of line signals is that not only are they easy to learn – and remember – but they can be readily adapted to underwater sound communication, either between the surface and the diver or diver to diver, by simply tapping ‘Pulls and Bells’ on suitable metal objects beneath the surface.
SINGLE-LIFELINE CODE
Attendant to Diver – General Signals
1 Pull – To call attention prior to sending a message, or
to check that diver is OK?
2 Pulls – Am sending down a rope’s end (or as previously arranged.)
3 Pulls – You have come up too far.
Go down slowly till we stop you.
4 Pulls – Come Up.
4 Pulls followed by
2 Bells – Come up, hurry up.
4 Pulls followed by
5 Bells – Come up to your safety float.
Direction Signals
1 Pull – Search where you are.
2 Bells – Go to the end of distance line or Jackstay.
3 Bells – Face shot line then go right.
4 Bells – Face shot line then go left.
5 Bells – Come into the shot line or turn back if on a jackstay.
Diver to Attendant – General Signals
1 Pull – To call attention.
Made bottom.
Left bottom.
Reached end of jackstay.
I am well.
2 Pulls – Send me down a rope’s end (or as previously arranged)
3 Pulls – I am going down.
4 Pulls – May I come up?
4 Pulls followed by
2 Bells – I want to come up. Assist me up.
4 Pulls followed by
5 Bells – May I come up onto my safety float?
Succession of Pulls (must
be more than 4) – EMERGENCY SIGNAL. Pull me up IMMEDIATELY
Succession of 2 Bells – Am foul and need the assistance of another diver
Succession of 3 Bells – Am foul but can clear myself if left alone.
4 Pulls followed by
4 Bells – Attend telephone.
Working Signals
1 Pull – Hold on or stop
2 Bells – Pull up.
3 Bells – Lower
4 Bells – Take up slack lifeline, or
You are holding me too tight.
5 Bells – Have found, started, or completed work.
Buddy Lines
Although there’s seldom a need for their use in ‘normal’ recreational diving, buddy lines that link a pair of divers together offer the same facility for passing messages back and forth between them as does a surface-to-diver umbilical.
Tactile Signals
There would be few divers who, at one time or another, have not experienced some minor degree of anxiety about the dive. In those situations contact with another human being will usually have a positive and re-assuring effect.
In certain situations, (such as a silt-out; a catastrophic failure of a primary and back-up light; or an equipment failure) it may often be necessary for divers to swim together side-by side. Holding hands may not do much for a macho diver’s image, but it does help maintain contact; can have a calming influence on the diver being assisted, and does allow for communication through hand pressure.
Once again the Pulls and Bells code used in line signals can be readily adapted to hand squeezes.
— ENDS—
Categories: General
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