Which depth has a single depth limit of 15 minutes?

• A. 25 fsw
• B. 40 fsw
• C. 30 fsw
• D. 50 fsw

Answer: (B)

Understanding no-decompression limits at a given depth helps you plan a dive that stays within safe limits without needing decompression stops. A single-depth dive means you plan to stay at one depth for your entire bottom time and then ascend directly to the surface without any decompression stops.

In the dive tables used for this course, the depth that allows a bottom time of 15 minutes without decompression is 40 fsw. That’s why 40 fsw is the correct choice: it matches the 15-minute single-depth limit on the table. At shallower depths, the no-decompression limit is longer than 15 minutes, and at deeper depths, it’s shorter than 15 minutes, so they don’t fit the 15-minute single-depth criterion. If you stayed at 40 fsw for more than 15 minutes, you’d exceed the no-decompression limit and would need to plan decompression stops.