A diving team is a group of people who work together to conduct a diving operation. A characteristic of professional diving is the specification for minimum personnel for the diving support team. This typically specifies the minimum number of support team members and their appointed responsibilities in the team based on the circumstances and mode of diving, and the minimum qualifications for specified members of the diving support team. The minimum team requirements may be specified by regulation or code of practice. Specific appointments within a professional dive team for which competences are specified and registration may be required are listed below. 
There is considerable difference in the diving procedures of professional divers, where a diving team with formally appointed members in specific roles and with recognised competence is required by law, and recreational diving, where in most jurisdictions the diver is not constrained by specific laws, and in many cases is not required to provide any evidence of competence. In recreational diving there may be no team at all for a solo diver, a dive buddy is the default arrangement, a three diver team is fairly common for technical diving, and a major technical dive or expedition may have a fairly complex team including surface support personnel made up to suit the requirements of the dive plan. Recreational diving instructors often use an assistant to increase the number of learners they can safely manage in the water, and dive guides may use an assistant to help keep the group together and assist the customers in an emergency.
Core diving team
These are the personnel that are generally required to be present at a professional dive site during the diving operation.
The diving supervisor is the professional diving team member who is directly responsible for the diving operation's safety and the management of any incidents or accidents that may occur during the operation; the supervisor is required to be available at the control point of the diving operation for the diving operation's duration, and to manage the planned dive and any contingencies that may occur.
Details of competence, requirements, qualifications, registration and formal appointment differ depending on jurisdiction and relevant codes of practice. Diving supervisors are used in commercial diving, military diving, public safety diving and scientific diving operations. A diving supervisor is required for every diving operation. The supervisor must remain in the control area and be in control at all times during the diving operation. This generally implies being able to communicate with the divers and other team members.
Also referred to as the diver, this is the person who does the underwater work planned for the dive. There may be more than one working diver, and the working diver and bellman may alternate during a dive. Diving skills required depend on the mode of diving and equipment used, and work skills required depend on the job to be done. A working diver is by default necessary for a diving operation. Without the diver there is no diving operation.
The diver who is at all times during the dive ready to go to the assistance of the working diver and perform a rescue to recover the diver to the surface if necessary. Diving competence requirements are identical to those of the working diver, but underwater work skills are not relevant while acting as standby diver. In surface oriented diving the standby diver may wait at the diving operation control point, and in saturation diving the bellman is the standby diver, though an additional surface standby diver may be required to assist with technical problems at shallow depths. A standby diver is required for every diving operation, though in some circumstances two working divers may act as standby to each other when working in close proximity, in an arrangement similar to the buddy system.
The diver's tender, or dive attendant, is a person who may or may not be a qualified diver who assists the diver or standby diver to dress in and out, assists them entering and exiting the water, boarding the stage or wet bell, and manages the diver's umbilical at the surface where applicable. The bellman acts as the working diver's umbilical attendant from a wet or closed bell.
In some circumstances, when untethered scuba is used, there may not be a requirement for a tender, and appropriate assistance may be provided by one of the other team members. In other cases, where the working diver is required to enter a confined space underwater, an additional underwater tender may be needed to handle the diver's umbilical at the entrance or other place where the risk of snagging is high. In some cases the stand-by diver may do this job. In these cases the underwater tender must be a suitably equipped and qualified diver, and will generally also need a surface tender in addition to the working diver's surface tender.
Diving medical practitioner
A registered diving medical practitioner competent to manage diving injuries may be required to be available on standby off-site during diving operations. The DMP should have certified skills and basic practical experience in assessment of medical fitness to dive, management of diving accidents, safety planning for professional diving operations, advanced life support, acute trauma care and general wound care. Depending on jurisdiction, a DMP may be required on telephonic standby for all commercial diving operations. For mixed gas and saturation diving the DMP should be competent to manage treatment for injuries associated with that class of diving.
Additional members depending on circumstances
The use of more complex equipment or diving modes may necessitate the inclusion of additional members in the diving team. Some of these are required to be registered operators, others are only required to be competent at their allocated tasks.
For surface-supplied air diving using a low pressure compressor a competent person is needed to set up, start run and check the compressor and air delivery to the distribution panel. There may also be a high-pressure compressor for filling scuba cylinders and high pressure reserve air cylinders for divers or decompression chambers, and this too should be operated by a competent person.
If an open or closed bell which provides gas to the diver from a bell panel is to be used to convey the divers to the worksite, a bellman is required. The bellman is a diver who acts as standby diver and diver's attendant from the bell during the dive, and may alternate as working diver during the dive if appropriately competent for the diving task. The bellman may be required to leave the bell to go to the assistance of the working diver, recover a disabled diver to the bell and provide first aid in the bell. Diving competence requirements are identical to those of the working diver, but underwater work skills are not relevant while acting as the bellman.
Launch and recovery system winch operator
A competent person responsible for operating the bell or stage lifting winch and launch and recovery system (LARS) is needed when such equipment is used. This is not a diving post.
A chamber operator is needed if there is a decompression chamber on site. The chamber operator is a person competent to operate a hyperbaric chamber with a compressed air atmosphere under the direction of a diving supervisor. This is not a diving post, but the chamber operator may also be a diver, and many surface supplied air divers are also qualified as chamber operators. The chamber operator is competent to prepare the chamber for an operation, blow it down to depth, communicate with the occupants and the supervisor, operate the main and medical locks, provide decompression gases on the built-in breathing system, monitor and maintain the chamber atmosphere composition and pressure within the prescribed limits, manage contingencies, decompress to follow a specified surface decompression or recompression treatment schedule, and perform basic maintenance procedures, including cleaning and inspecting the components for correct function.
A gas man, also called rack operator, is required when gas mixtures other than air are to be provided to the diver. This person controls the gas supply to the diver and may also handle communications as a direct assistant to the supervisor. The gas man may also be a diver, but the specific activity is not a diving post.
Diving medical technician
A diving medical technician is necessary where the diving operation is remote from hospital facilities, such as in offshore work. A diver medic or diving medical technician (DMT) is a member of a dive team who is trained in advanced first aid. A Diver Medic recognised by IMCA must be capable of administering First Aid and emergency treatment, and carrying out the directions of a doctor pending the arrival of more skilled medical aid, and therefore must be able to effectively communicate with a doctor who is not on site, and be familiar with diving procedures and compression chamber operation. The Diver Medic must also be able to assist the diving supervisor with decompression procedures, provide advice as to when more specialised medical help should be requested, and must be fit to provide treatment in a hyperbaric chamber in an emergency, and must therefore hold a valid certificate of medical fitness to dive. The diver medic may also be a diver, but this is not a diving appointment. Training standards for Diver Medic are described in the IMCA Scheme for Recognition of Diver Medic Training.
A person competent to maintain, repair and test the function of the diving and support systems and components for which they are appointed as systems technician. A systems technician would typically be required for a team operating a saturation system, or a surface supplied diving operation with a significant amount of support equipment, or relatively complex support equipment, or where a large number of dives are planned, and on-site maintenance and repair work is likely to be needed. This is not a diving appointment, though the technician may also be a diver.
The diving superintendent is the management position covering diving operations. The superintendent is usually a qualified supervisor, but depending on the organisation, may not be required to supervise dives. The superintendent may oversee saturation and surface oriented diving operations on air or mixed gases, develop and implement dive plans and diving related company procedures and manage diving related activities to minimise health, safety and environmental risks and impacts. This is not a diving appointment and the superintendent may not be directly involved in the actual diving operations.
Life support technician
A life support technician is a person registered as competent to operate the life-support systems of a mixed gas saturation diving system. Divers living in saturation conditions must be continuously monitored and the pressure, oxygen and carbon dioxide content of their breathing gas, and temperature and humidity of the environment must be monitored and controlled. Functions such as feeding and sewage disposal and locking stores and equipment into and out of the chambers are also controlled from outside by life support personnel. Responsibilities include communication with the divers in saturation, supervising transfer of personnel into and out of the accommodation chambers, maintaining the hyberbaric rescue craft and hyperbaric evacuation of the divers in an emergency. This is a non-diving post.
Life support supervisor
The life support supervisor is a senior life support technician appointed by the diving contractor to supervise operation of the saturation life support systems. This is a non-diving post.
Whenever a remotely operated vehicle is operated at a dive site when a diving operation is taking place, competent personnel are required to run the ROV, and as the safety of the divers is influenced, the ROV team is under the authority of the diving supervisor. The ROV can be both a hazard because of its mass, power and moving parts, and a benefit to diver safety, as it can monitor the divers on closed circuit video, and give some kinds of assistance in contingencies. There are a range of tasks where a ROV is more suitable than a diver, and others which a diver can do better. The ROV team are not necessarily divers, though it is possible. ROV operation requires a different set of skills and knowledge to diving.
A person trained and competent to operate a remotely controlled underwater vehicle. In diving operations the pilot must be competent to safely operate the ROV with divers in the water. ROV pilots are usually also trained in routine maintenance and minor repair of the ROV.
A senior ROV pilot appointed to supervise the ROV team. The ROV supervisor is under the authority of the diving supervisor when divers are in the water, but may work autonomously when there is no diving taking place.
When the minimum personnel in a diving team is regulated in terms of national or state legislation, the legal status and responsibilities of the members is generally defined in the legislation. These responsibilities often relate to occupational safety and health and specify a duty of care for the team members.
Technical divers may form teams where this is appropriate to support each other for complex or hazardous dives. This can include surface co-coordinators, equipment handlers, gas blenders, support and standby divers, and any other function that may seem useful to them. The team members are not usually contractually bound and have no duty of care beyond what they may have voluntarily assumed and that of ordinary citizens. The divers remain responsible for their own assumption of risk and are not under the direction of anyone other than themselves and the dive plan by group consensus. Technical divers may also refer to team diving where a group of three divers assume the roles of dive buddies to each other.
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