A PRIMARY SKILL THAT ALL DIVERS require for open-water diving is the ability to navigate under water.
While maintaining positional awareness may be a simple matter in clear, calm waters and at relatively shallow depths, the demands increase dramatically when divers have to contend with environmental challenges such as reduced visibility or currents.
The process of maintaining orientation and getting around in the underwater world can be tricky, but it is of course essential to safe, stress-free diving.
All too often, divers are unable to maintain positional awareness, and have to take steps to re-orient themselves.
To get a better handle on the navigational challenges faced by divers, Scuba STAR Network recently conducted a safety survey. This looked at the types of navigational techniques and tools used by divers, and at the difficulties they occasionally encounter.
Some preliminary results were what we might have expected, but there were a few surprises as well, and some valuable lessons to be learned.
Roughly half the respondents to the safety survey (many of whom were DIVER readers) usually engage in beach diving from the shore, with the rest split fairly evenly between those who engage in stationary (anchored or moored) boat-diving, and those who more often participate in drift or "live" boat-diving.
The respondents represented a spectrum of training and experience, with the majority having logged more than 250 dives.
Forty per cent were instructors, and a similar number held advanced certifications such as Rescue Diver or Divemaster.
Some 60% of respondents reported that they were responsible for navigation on most or all of their dives (7-10 out of 10 divers).
Another 30% reported that they were responsible for the navigation either sometimes (on 3-6 out of 10 dives) or occasionally (1-2 out of 10 dives).
Divers primarily use three navigation techniques - natural, compass or a combination of the two.
Natural navigation, the most basic, involves using underwater landmarks to maintain orientation. Compass navigation is more applicable to environments lacking in landmarks, and is often used when visibility is reduced or limited. Divers use the compass to navigate along a course, employing various techniques to measure distance travelled.
According to the survey, more than 70% of the divers use natural navigation as their primary technique on some or most of their dives. Compass navigation is reportedly used less frequently (55%) on some or most dives. A similar percentage of divers report that they combine the two techniques on some or most dives.
Very few of the respondents appeared to take advantage of electronic navigation devices - 83% said they never used them.
Those who did use them were usually referring to electronic compasses, watches and dive computers rather than sonar-based systems.
The three primary means of measuring distance under water are timing, counting kicks, and monitoring air consumption. While each method can be used successfully, each has inherent limitations as well.
The greatest number of divers (51%) reported having the most success using timing to measure distance, 21% preferred using air consumption, and 11% favoured counting their kicks.
As we all recognise, underwater navigation can be a challenge. Only 2% of the respondents claimed that they never had problems.
Nearly 90% reported that they experienced problems either rarely (fewer than one in 10 dives) or occasionally (1-2 out of 10 dives).
The most common results of navigational problems include difficulty locating the boat or exit point (reported by 68%), and not having the precision they would like (reported by 64%).
Nearly a quarter of the divers said they had experienced running low on air before reaching the boat/exit point, and 13% reported having difficulty interpreting or using the compass.
A variety of factors can influence our success with maintaining underwater orientation (see the table below).
It is little surprise that poor visibility and currents contribute to navigational errors and, considering the high reliance on natural navigation techniques, it is also no surprise that an environment lacking underwater landmarks should complicate divers' navigational efforts.
Perhaps more surprising are the number of divers who report buddy-related problems (32%) and distraction (42%) as contributing factors.
Surprisingly, about one in five divers reported distraction as the top factor causing errors in underwater navigation. While the high reporting of this factor might be due to the fact that so many of the respondents are instructors, it is nonetheless a factor that divers should consider as part of their overall dive plan.
Naturally, other factors than those listed below can come into play on a dive. These include the effects of large iron deposits such as shipwrecks, which can interfere with the operation of a magnetic compass.
Obviously, changing conditions during a dive (alterations in currents or visibility) can greatly influence even the best-laid navigational plans. One diver commented that one of his legs seems to be stronger than the other, and that his asymmetrical kicking tended to make him go in a circle unless he was paying close attention.
Navigation can be a significant stressor for divers. One in three divers reported having experienced anxiety or panic as a result of navigational problems under water.
One potential consequence of navigation problems on a dive is the need for divers to surface at some point to regain orientation.
Surfacing in the middle of a dive can alter the profile in a negative manner, perhaps increasing the risk of DCI or pressure-related injuries.
If only one diver in a pair surfaces for a navigation check, this might heighten the safety risks for the remaining (solo) diver.
The results of the Scuba STAR Network safety survey suggest that underwater navigation is one area in which many divers can improve their skills and comfort.
While 30% report that none of the navigation techniques is more challenging than the others, one in three reported that they found compass navigation the most challenging method.
More than 10% of respondents reported that
a lack of underwater references was the most common problem in navigation, suggesting a need to shift from natural navigation to greater reliance on compass techniques.
Divers certainly have a lot to gain from sharpening their compass navigation skills, especially considering that poor visibility is reported as the most common factor adversely affecting navigation.
Such skills can be honed on underwater navigation courses, as well as through practice drills conducted on land or under water.
The results of the survey might also suggest that divers can enhance their navigational abilities by focusing on certain other aspects of their diving. Having to resolve problems with
a buddy (or student) on a dive can be a major distraction, and can throw a monkey wrench in the navigational gears of any diver.
Our navigation capabilities might also be improved by making efforts to limit other forms of distraction, as well as maintaining workload at a reasonable level for the diver charged with navigation.
Just over 50% of the respondents to the Scuba STAR survey reported that they included a discussion of underwater navigation as part of their pre-dive briefing.
Perhaps by putting more emphasis on this aspect of safe diving we can stay on course, and get where we're going with safety and confidence.
Robert Rossier invites divers to visit www.scubaSTARnet.com to participate in future safety surveys and to report equipment, training and procedure-related diving incidents.
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