If a dive team went to 60 feet for 40 minutes and surfaced for one hour, how long can they dive if they want to do a second dive to 50 feet?

To determine the allowable duration for a second dive to 50 feet after previously diving to 60 feet for 40 minutes and surfacing for one hour, it’s important to consider residual nitrogen levels in the body and the use of a dive table or computer.

After a dive, the body absorbs nitrogen, and it takes time for the body to off-gas that nitrogen, which occurs during the surface interval. Based on recreational diving guidelines, the more time spent at depth during the first dive and the deeper the dive, the more nitrogen is absorbed. The one-hour surface interval allows for some off-gassing but may not be sufficient for longer or deeper dives following a previous dive.

When planning the second dive to 50 feet, specific recommendations often suggest limiting dive time based on the residual nitrogen from the first dive. The data shows that, typically, allowable dive times may be shorter after deeper or longer previous dives. Given that a dive to 60 feet can have a considerable residual effect, a more conservative dive limit would be expected for a dive to 50 feet.

In this case, it is deduced that 30 minutes would be the maximum safe duration for the second dive when considering the previous nitrogen absorption and surface time. Therefore, the selection