What is the maximum allowable bottom time for a dive to 20 meters (66 feet) according to IANTD air dive tables?

The maximum allowable bottom time for a dive to 20 meters (66 feet) according to IANTD air dive tables is indeed aligned with the reference material for recreational diving. At this depth, the accumulation of nitrogen in the body increases, requiring careful management of bottom time to prevent decompression sickness.

The 60 minutes identified as the correct answer balances safe dive practices with the physiological limits imposed by nitrogen uptake. This value is generally supported by the need to allow for adequate surface intervals and provisions for safety stops on ascent. By adhering to these guidelines, divers can minimize the risk of nitrogen narcosis and ensure better safety during their dives.

The context provided by the other options indicates varying times that either exceed the safe limits established in the dive tables for this depth or do not align with the recommended practices for safe diving durations. By understanding these parameters, divers become more equipped to plan dives effectively, ensuring safety and enjoyment underwater.