The pre-dive safety check must not be carried out only with first-time divers, or only with those who have not yet acquired sufficient confidence with diving procedures and diving equipment. The use of check lists or flows is useful for divers of any grade to reduce the problems resulting from forgetfulness or moments of inattention that can affect every individual regardless of the level of competence achieved.
Forget the belt of the lead on boarding, do not completely close the hinge of a half-tank or, even worse, of a watertight, overlap the belt straps or do not carefully fasten the closures of the bump on the tank, are some examples of forgetfulness in which it is not difficult to incur at least once in your life.
The Padi IDC Australia procedure should be recommended for each pair of dives as it achieves the dual purpose of carry out a double check. Even those who are subjected to control follows the various phases, thus being able to see if something is missing or out of place.
Be sure that both members of the couple (or carer) know the type of equipment of the other (buttons on the gav, taps, etc.) and its precise location (2nd regulator, quick stop, belt buckle of ballast, etc.).
Based on this knowledge it is possible to assign specific responsibilities and draw up the composition of the groups. The country’s diving federations and associations accept in their regulations at most a ratio of 1 Instructor + 1 Instructor Help (or companion with Underwater Salvage Patent) every 6 students.
This 2 to 6 Padi IDC Australia ratio is extended in the agreements of the RSTC (Recreational Scuba Training Council, together with the 9 US agencies that teach scuba diving) to 1 Instructor + 1 Certified assistant every 10 students (but un instructor alone can accompany up to 8). More similar to the country’s indications are the directives of the BSAC (British Sub-Aqua Club, reference organization for Anglo-Saxon diving) which suggest a maximum of 1 instructor for every 6 students if the environmental conditions are optimal: calm sea, warm waters, good visibility; however, the use of an escort is recommended to close the dive group.
Therefore there are no univocal indications regarding the correct relationship between instructors and students. Even less clear are the indications relating to the relationship between carers and accompanying persons, if the latter are already patented. In fact, there are too many variables: patent level, course date, sea state, previous knowledge of individuals.
A valid advice in general is to accompany only a few divers at a time, possibly getting help from another companion. The importance of having 2 people with the qualification to accompany is evident in several cases.