A diver dives to 50' for 30 minutes, surfaces for 8 minutes, and then dives to 40' for 45 minutes. What will the diver's letter group be at the end of these dives?

To determine the diver's letter group after the dives, it's essential to understand how nitrogen loading works during consecutive dives within specific depths and times. Each depth and time of immersion contributes to the diver's nitrogen saturation, which is tracked using tables or computers that translate dive profiles into letter groups.

In this case, the diver first goes to 50 feet for 30 minutes. At this depth, the diver will accumulate a certain amount of nitrogen based on the dive duration, which will push the diver into a specific letter group after surfacing.

After surfacing for 8 minutes, the nitrogen in the body begins to off-gas, particularly because the surface interval provides some time for nitrogen to dissipate. However, since the surface interval is not very long, the diver retains a significant amount of nitrogen.

Then, the diver dives again to 40 feet for 45 minutes. This second dive will further increase the diver’s nitrogen saturation. The longer duration at this less deep depth, combined with the previous nitrogen load, plays a critical role in determining the letter group after completing both dives.

Ultimately, the calculations based on these dive profiles indicate that the combined nitrogen absorption from both the dives, in conjunction with the short surface interval, results in the diver ending