Diver training
Diver training is the set of processes through which a person learns the necessary and desirable skills to safely dive underwater within the scope of the diver training standard relevant to the specific training programme. Most diver training follows procedures and schedules laid down in the associated training standard, in a formal training programme, and includes relevant foundational knowledge of the underlying theory, including some basic physics, physiology and environmental information, practical skills training in the selection and safe use of the associated equipment in the specified underwater environment, and assessment of the required skills and knowledge deemed necessary by the certification agency to allow the newly certified diver to dive within the specified range of conditions at an acceptable level of risk. Recognition of prior learning is allowed in some training standards.
Recreational diver training has historically followed two philosophies, based on the business structure of the training agencies. The not-for profit agencies tend to focus on developing the diver's competence in relatively fewer stages, and provide more content over a longer programme, than the for-profit agencies, which maximise profit and customer convenience by providing a larger number of shorter courses with less content and fewer skills per course. The more advanced skills and knowledge, including courses focusing on key diving skills like good buoyancy control and trim, and environmental awareness, are available by both routes, but a large number of divers never progress beyond the entry level certification, and only dive on vacation, a system by which skills are more likely to deteriorate than improve due to long periods of inactivity. This may be mitigated by refresher courses, which tend to target skills particularly important in the specific region, and may focus on low impact diving skills, to protect the environment that the service provider relies on for their economic survival.
Diver training is closely associated with diver certification or registration, the process of application for, and issue of, formal recognition of competence by a certification agency or registration authority. The training generally follows a programme authorised by the agency, and competence assessment follows the relevant diver training standard.
Training in work skills specific to the underwater environment may be included in diver training programmes, but is also often provided independently, either as job training for a specific operation, or as generic training by specialists in the fields. Professional divers will also learn about legislative restrictions and occupational health and safety relating to diving work.
Sufficient understanding of the hazards associated with diving activities is necessary for the diver to be competent to reasonably assess and accept the risk of a planned dive. The professional diver can to some extent rely on the diving supervisor, who is appointed to manage the risk of a diving operation, and a diver in training can expect the instructor to adequately assess risk on training dives. Certification agencies minimise their responsibility by limiting the conditions in which the diver is considered competent.
Comparison between recreational and professional diver training
Both recreational and professional diving occur in the underwater environment, which presents the same basic hazards to both groups. The professional diver has a job to do in this environment, which may expose them to additional hazards associated with the work. The recreational diver usually has no legal duty of care to other divers. The duty of care to a recreational dive buddy is poorly defined and with some exceptions, the diver is not legally obliged to dive with a buddy unless they choose to. The professional diver is a member of a diving team and has legally defined duty of care to other members of the team.Recreational diver training prepares the diver for low stress diving in an environment similar to the one they were trained in, using equipment similar to that used in training. Professional diver training prepares the diver for a working environment in which the diver is expected to work as a member of a team, and be involved in organisation, planning, setting up of the infrastructure, selection and maintenance of the diving and work related equipment, where conditions may be less than ideal, and there may be time constraints. The professional diver must be able to make a realistic and informed decision on acceptability of risk.
Recreational diver training is regulated within the recreational diver training industry, within each certification agency, and tends to be kept to a minimum to keep costs down in a competitive environment, and because of customer pressure to minimise the effort involved. Consequently, the entry level certification for most recreational divers advises them to dive only in conditions similar to those in which they were trained, and to a maximum depth of 18 m, with no decompression obligation. This also encourages the diver to attend further training if they wish to achieve more than minimum competence. The training is short, convenient, and minimal. The cost is low in absolute terms, but accumulates with further training, for those few who undertake it. Professional diver training, and the associated assessment and certification of competence, are usually based on occupational health and safety legislation, and also covered by the employer's duty of care. The training standards are usually aligned with internationally recognised standards, and are expected to follow quality assurance procedures. The professional diver with entry level qualification is expected to perform duties as working diver, diver's attendant, and standby diver, and must be competent and fit to perform all these tasks, as well as the basic skills of staying alive underwater and not getting injured, and the work involved in setting up the site and demobilisation after the job.
Prerequisites
The entry requirements for diver training depend on the specific training involved, but generally include medical fitness to dive.Fitness to dive,, is the medical and physical suitability of a diver to function safely in the underwater environment using underwater diving equipment and procedures. Depending on the circumstances it may be established by a signed statement by the diver that he or she does not suffer from any of the listed disqualifying conditions and is able to manage the ordinary physical requirements of diving, to a detailed medical examination by a physician registered as a medical examiner of divers following a procedural checklist, and a legal document of fitness to dive issued by the medical examiner.
The most important medical is the one before starting diving, as the diver can be screened to prevent exposure when a dangerous condition exists. Other important medicals are after some significant illness where medical intervention is needed. This has to be done by a doctor who is competent in diving medicine, and can not be done by prescriptive rules.
Psychological factors can affect fitness to dive, particularly where they affect response to emergencies, or risk taking behaviour. The use of medical and recreational drugs, can also influence fitness to dive, both for physiological and behavioural reasons. In some cases prescription drug use may have a net positive effect, when effectively treating an underlying condition, but frequently the side effects of effective medication may have undesirable influences on the fitness of diver, and most cases of recreational drug use result in an impaired fitness to dive, and a significantly increased risk of sub-optimal response to emergencies.
Formal educational prerequisites are variable. Diving skills are largely physical, but for professional diving a measure of literacy and numeracy is necessary to allow a reasonable chance of success with the theoretical knowledge requirements, and for effective on-site communication within the dive team. The international lingua franca of offshore diving operations is English.
Some training standards include an ability to swim as a prerequisite.
Format
Diver training is a form of competency-based adult education that generally occurs at least partly in a formal training environment for the components specified by diver training standards and for which certification is issued. There are also non-formal and informal aspects where certified divers extend their competence and experience by practicing the basic skills and learning other complementary skills in the field.Prior learning may be recognised where applicable and permitted by the training standard. This is typically done by assessment against the requirements of the standards using the same methods as in formal training programmes for safety-critical skills and knowledge, and by accepting verifiable evidence of experience, as in signed and witnessed logbook entries.
Diving theory
Diving theory is the basic knowledge of the physical and physiological effects of the underwater environment on the diver.Diving physics
Diving physics are the aspects of physics which directly affect the underwater diver and which explain the effects that divers and their equipment are subject to underwater which differ from the normal human experience out of water. These effects are mostly consequences of immersion in water, the hydrostatic pressure of depth and the effects of the pressure on breathing gases. An understanding of the physics is useful when considering the physiological effects of diving and the hazards and risks of diving.Diving physiology
Diving physiology is the physiological influences of the underwater environment on the physiology of air-breathing animals, and the adaptations to operating underwater, both during breath-hold dives and while breathing at ambient pressure from a suitable breathing gas supply. It, therefore, includes both the physiology of breath-hold diving in humans and other air-breathing animals, and the range of physiological effects generally limited to human ambient pressure divers either freediving or using underwater breathing apparatus. Several factors influence the diver, including immersion, exposure to the water, the limitations of breath-hold endurance, variations in ambient pressure, the effects of breathing gases at raised ambient pressure, effects caused by the use of breathing apparatus, and sensory impairment. All of these may affect diver performance and safety.Immersion affects fluid balance, circulation and work of breathing. Exposure to cold water can result in the harmful cold shock response, the helpful diving reflex and excessive loss of body heat. Breath-hold duration is limited by oxygen reserves, and the risk of hypoxic blackout, which has a high associated risk of drowning.
Large or sudden changes in ambient pressure have the potential for injury known as barotrauma. Breathing under pressure involves several effects. Metabolically inactive gases are absorbed by the tissues and may have narcotic or other undesirable effects, and must be released slowly to avoid the formation of bubbles during decompression. Metabolically active gases have a greater effect in proportion to their concentration, which is proportional to their partial pressure, which for contaminants is increased in proportion to absolute ambient pressure.
Work of breathing is increased by increased density and viscosity of the breathing gas, artifacts of the breathing apparatus, and hydrostatic pressure variations due to posture in the water. The underwater environment also affects sensory input, which can impact on safety and the ability to function effectively at depth.