What is the main subject of operational instructions in regards to diving?

The main subject of operational instructions in regards to diving focuses on safety protocols and procedures. These instructions are critical because they provide divers with guidelines to ensure their well-being and enhance the safety of the dive operation. This includes essential information such as pre-dive briefings, dive plans, communication signals, limits for depth and time, buddy system protocols, and measures to prevent accidents such as decompression sickness and equipment failures. Safety is paramount in diving, as it directly impacts the health and safety of every participant.

While equipment maintenance schedules, historical records, and emergency response training are important aspects of diving operations, they serve as supplementary components to the overall safety framework. Maintenance schedules ensure that diving equipment functions correctly, historical records may help understand trends in divers' experiences, and emergency response training prepares divers for unforeseen situations. However, without a solid foundation of safety protocols and procedures, none of these elements can effectively contribute to a safe diving environment.