The dive guide ties a descent line into the wreck. In this case his support diver can be summoned using a voice communication system, but how many guides carry out similar tasks alone

OVER THE PAST 20 YEARS, many previously taboo diving practices have entered the mainstream. Dive computers are no longer reviled, they are now devices to be loved and encouraged, even for entry-level training. PADI (through DSAT) now believes that decompression diving does exist. BSAC, PADI and other sport-diving organisations now extol nitrox as being good for you, rather than a ticket to instant death.
Not only is trimix accepted as a means of diving deeper than air-diving limits, it is even encouraged within deeper air limits as a safety measure to reduce narcosis. Rebreathers, while too expensive to be commonplace, are generally accepted.
The funny thing is that the pioneering users of all of these ways and means have also historically been the greatest practitioners of solo diving: cave-divers.
Cave-divers have been diving solo for far longer than we have been using all these technology-based newcomers to recreational diving. Even more remarkable, their reason is that, when the caves are tight and muddy, diving alone is actually safer.
Never dived solo Think again. In normal open-water sport diving, many divers are effectively diving solo even when they have a buddy.
Many dive guides lead groups of divers who would not be capable of rescuing the guide if the guide should get into trouble. Before the customers enter the water, dive guides often have to secure a descent line, check the placement of a shot or make a quick reconnaissance of the dive site and conditions. And they nearly always do it solo.
When an underwater photographers is concentrating on taking pictures, he may have a
buddy looking out for him, but who is looking out for his buddy
The same can be said of any diver concentrating on a task, be it surveying marine life or filling a lift-bag. This situation is recognised at the very core of commercial diving practices. Rather than buddy teams, each diver at work has a support diver, whose sole purpose is to be ready to assist the diver at work.
When an instructor is teaching a beginner, could the beginner rescue the instructor Professional instructors in the UK are required to have a supporting divemaster, so that this situation does not arise. But such rules do not apply overseas, where an instructor is often teaching a group of students with no divemaster to assist.
Even in the UK, most instructing within dive clubs is done without the support of an experienced buddy for the instructor. An instructor in a BSAC or SAA club could effectively be diving alone.
Getting away from the specific cases of instructors and divemasters, when a parent is diving with a child, he or she may be there to look after his or her offspring, but, should that parent have a problem, is the child physically capable of lending assistance
Then consider an average holiday dive, with or without the services of an inwater dive guide.
When you turn up at the dive centre and are paired up with a buddy you have never met before, it could be the perfect partner for you or, at the other extreme, it could be the buddy from hell. In the latter case, you may effectively be diving solo.
Quite likely, it will simply be an average buddy who pays the same amount of attention to you as you do in return. When conducting your leisurely dive, will you be close enough to assist each other if needed, or will the pair of you be subscribing to the same ocean buddy system
Scuba Diving International, the sport diving arm of TDI, has a course entitled Solo Diving, though UK manager Stephen Phillips stresses that this is not a qualification for diving alone.
It is training in self-sufficient diving practices to make sure that, should you end up without a buddy to assist, you have the best preparation to sort yourself out. Its the self-sufficient approach technical divers take for granted, but geared towards sport divers.
Whether you plan to dive alone or simply want to prepare for the worst case when diving with a buddy, planning your dive with soloing in mind is a survival skill from which we can all benefit.

A good staring point is a risk assessment (Plan Like A Pro, July 2007), a formalised way of listing what the hazards are and how they could affect us, with a corresponding analysis of what we could to do about them.
In the context of diving solo, having identified the hazards, we have to analyse how they could be controlled should a buddy be able to help, then make a second analysis on how they could be controlled should we have to sort ourselves out.
Where these differ represents the change in risk.
It may be greater, it may be smaller, or it may simply be different.
The sort of things that will change in the risk assessment are running out of gas, regulator failure, entrapment and entanglement, physiological problems such as hyperoxia, hypercapnia, barotrauma and decompression sickness while under water, and medical problems like heart attacks while under water. An experienced diver may also want to consider the risk of a problem with a buddy leading him into trouble.
As taught in any rescue course, far the best strategy is to avoid having a problem in the first place. Preventative measures are even more important to the solo or virtually solo diver, where the assistance of another diver cannot be assumed.
Here are a couple of examples to point you in the right direction. The buddy-based control measures have been left out, because all divers should already be familiar with these.

Running low or out of gas can lead to:
width=100% Drowning.
width=100% Decompression illness through missed deco.
width=100% Barotrauma through rapid ascent.

width=100% Conservative gas planning.
width=100% Ensure that cylinder-pressure gauge is accurate and does not stick on the way to zero.
width=100% Regularly check cylinder pressure.
width=100% Be aware of a regulator feeling tight when cylinder pressure is getting very low.
width=100% Stay within a depth/time from which a free- swimming ascent is possible and an
acceptable risk.

width=100% Free-swimming ascent.
width=100% Switch to back-up or redundant supply.

Note here that older and lower-performance regulators often give a better feel for when a cylinder is nearly empty than modern high-performance regulators.
Regulator failure can lead to accelerated or sudden loss of gas, leading rapidly to the same consequences as running out of gas.
As for running low or out of gas, in addition:

width=100% Use reliable and well-maintained regulators.
width=100% Regulators should be dived-in, that is, not new or fresh from a service.
width=100% Use regulators suited to the environmental conditions.
width=100% Inspect hoses regularly for wear or damage.
width=100% Be aware of unusual regulator behaviour.
width=100% Check for creep before diving.
width=100% Check for leaks before diving and at the start of the dive.

width=100% Control free-flowing gas using cylinder tap

Notes here would include the fact that creep of inter-stage pressure may show up as a hissing of gas being released by the second stage if the cylinder is left on and the regulator is undisturbed for a few minutes before kitting up.

Kit configuration needs to be self-sufficient. Solo divers need to carry one of everything and two or more where the risk assessment dictates.
They must be capable of using it unassisted, so their kit needs to be configured so that they can reach everything without the help of a buddy.
A buddy pair may be in the habit of carrying one delayed surface marker buoy and reel between them, helping each other to send it to the surface at the end of a dive.
Self-sufficiency means that each diver should carry his own DSMB and reel, and be capable of retrieving it from a pocket, launching it proficiently without the assistance of a buddy, and managing his own ascent.
Each diver should also have a full set of instruments, and be capable of monitoring them to manage and navigate the dive. The standards say this anyway, but how often have you seen a buddy pair with one compass between them
On a night dive, it means that each diver should carry a back-up light, rather than one between each pair. We need to qualify this; the recommendation for the number of lights carried on a night dive varies greatly between training agencies and between dive centres and clubs within the auspices of any single training agency.
When something works loose, like a weightbelt or cylinder camband, self-sufficiency dictates that divers should be competent to sort it out themselves, rather than relying on the assistance of a buddy. If a regulator begins to free-flow, they should be capable of reaching the cylinder tap to close it down or control their use of what remains.
All divers should already be carrying a knife, shears or other means of cutting a net or line.
Self-sufficiency means that, should they become entangled, they can remain calm and carefully cut themselves clear.
In some entanglements, this may actually be safer than allowing a buddy to approach the entanglement hazard and do the cutting. One of the first rules of rescue is that rescuers should not put themselves at undue risk.
On a wreck in low visibility where risk of entanglement is greater, a second or even a third knife may be a wise precaution. At the same time, prevention is always the first line of defence, and a clean and streamlined kit configuration is less likely to become badly tangled in the first place.

Carrying redundant gas supplies in a twin-set, or bail-out in a pony cylinder, is a specific case of self-sufficiency. However, neither of these is a pre-requisite for all solo-diving situations.
On a shallow dive that stays well clear of decompression and overhead environments, a free-swimming ascent may be a perfectly realistic option. On a very shallow dive, simply standing up could restore an infinite supply of fresh air.

One thing I wont do is encourage any individual to dive solo. Assuming that you are an experienced diver - or you wouldnt be considering diving solo - only you can decide if solo diving is for you.
Nevertheless, being self-sufficient in case you end up as an effectively solo diver makes sense for everyone. To quote Stephen Phillips: Every diver needs the skills taught in Solo Diving, but not every diver has the correct make-up to dive alone.
If you are tempted to go it alone, do so on dives well within your comfort zone, dives where the diving skills come automatically and there are no undue stresses to distract you from the first priority of rescue skills, staying out of trouble.
Weigh this up against the one undoubted virtue of buddy-diving: it is more sociable.

If you strayed into this net, could you cut yourself clear without assistance
Diver with a 7-litre independent twin-set
Twin take-off in a Y-valve.
Releasing a delayed surface marker buoy.
In the USA, where divers have been sued by a buddys relatives for not being able to complete a rescue when their buddy got into trouble, some divers advocate solo-diving to avoid litigation. While this may protect them from the relatives of a lost buddy, it does not necessarily protect the dive centre from the divers own relatives.
Such extremes are not the norm in the UK, but do check your insurance. Most insurance policies cover diving accidents when diving within your qualifications.
If you have a fatal accident while diving alone, will your life insurer pay up It may not matter to you, but it could matter a lot to your family. Check the small print.

(recent Divernet Forum poll of 26 divers)
Sometimes (10)
I regularly solo dive (6)
No, because its contrary to safety philosophy (6)
No, but sometimes Ive considered it (2)
No, because its contrary to all Ive been taught (1)
You must be joking! (1)

The objective of this course is to train divers in the benefits, hazards, and proper procedures for diving solo. Upon successful completion of this course, graduates may engage in solo-diving activities. This is from the SDI solo diver course standards.
The entry requirements are Advanced Diver with at least 100 dives. Kit must include a second regulator from an H-valve, pony or twin-set - not an octopus.
Course content includes gas-planning, contingency planning, equipment selection and configuration, self-reliance and self-rescue, managing stress, avoiding and dealing with entanglement.
Contact TDI/SDI UK, 02844 832992,,

Both BSAC and DAN conclude from incident-report statistics that a disproportionate number of incidents involve solo divers, and that a much greater proportion of incidents involving solo divers end up being fatal.
There could be some truth in the statistics, but as so often, it all depends on the data collected. While rescuing an out-of-gas buddy may be a reported incident for a buddy-pair, it would be a non-event and not reported by a solo diver who simply switched to a redundant or bail-out supply.
How many of the solo-diving incidents occurred on properly planned and equipped solo dives This information is not in the data.
How many of the solo incidents involved dives on which a buddy-assisted rescue would not have been possible, or where a rescue attempt would have resulted in a dual fatality Again, this information is not available.
For an evenly matched, properly equipped buddy pair on an average dive, the intuitive conclusion is that buddy-diving is safer. But these are the dives on which things are least likely to go wrong in the first place.
Solo diving does is potentially riskier, but with proper planning and equipment, it may be less so than incident reports suggest.
Even without such precautions, is solo diving really that dangerous If it were, there would be a stack of dead dive guides at just about every resort you visit.