What limits should be established prior to every scuba dive?

Establishing limits prior to every scuba dive is critical for safety and planning purposes. The chosen answer encompasses three vital parameters: maximum bottom time, maximum depth, and minimum air pressure.

Setting a maximum bottom time is essential to prevent exceeding the no-decompression limits, thereby reducing the risk of decompression sickness, which can occur if a diver stays underwater too long and ascends too quickly. The maximum depth guideline is equally important, as deeper dives increase the level of risk due to factors like nitrogen narcosis, increased pressure, and more severe effects of decompression.

Additionally, establishing a minimum air pressure, typically set above a certain threshold like 500 psi, ensures that divers maintain a safe reserve of air for emergencies or unexpected situations. This collective approach helps divers adhere to safe diving practices, planning their dives effectively and making informed decisions underwater.

In contrast, the other options do not fully address the crucial aspects necessary for a comprehensive dive plan, making the selection of maximum bottom time, maximum depth, and minimum air pressure the most complete and appropriate choice for pre-dive limits.