PADI Divemaster Certification Practice Exam

What is a crucial procedure for preventing gas narcosis during a dive?

1. Stay well within planned depth and time limits

2. Use a backup dive computer

3. Increase the dive depth gradually

4. Avoid using dive suits

The correct answer is: Stay well within planned depth and time limits

Staying well within planned depth and time limits is a crucial procedure for preventing gas narcosis during a dive. Gas narcosis, often referred to as "the rapture of the deep," occurs when divers descend to depths typically beyond 30 meters (approximately 100 feet). At these depths, the partial pressure of nitrogen increases, which can lead to narcotic effects on the nervous system. By adhering to planned depth limits and controlling the time spent at depth, divers can mitigate the risk of experiencing these effects. Using a backup dive computer and increasing dive depth gradually are good practices for overall safety but are not directly aimed at preventing narcosis. A backup dive computer is helpful for redundancy in case of equipment failure, while increasing depth gradually primarily focuses on preventing decompression sickness rather than specifically addressing narcosis. Avoiding dive suits is not relevant to preventing gas narcosis, as suits are generally used for thermal protection and do not impact the effects of nitrogen in the body. Thus, the most effective way to prevent gas narcosis is to stay within the established depth and time limits during a dive.