Who defines the ascent rate and required decompression stops for a dive?

• A. The diver's personal preference.
• B. The surface operations manager based on schedule only.
• C. The weather briefing and sea conditions.
• D. The Dive Plan or decompression schedule.

Answer: (D)

The ascent profile and decompression stops come from the Dive Plan or decompression schedule. This plan is created by qualified dive professionals (or by the decompression model built into a dive computer) and intentionally map out how fast you ascend and when and where you pause to off-gas inert gases. It uses depth, bottom time, gas mix, and a chosen decompression model to calculate safe stop depths and durations, ensuring a controlled, gradual pressure change. Relying on personal preference, or on surface crew schedules or weather/sea conditions alone, can ignore the physiological limits of gas exchange and lead to dangerous outcomes. The weather or sea state mainly affects site choice and general safety, not the specific decompression requirements, which are defined by the planned ascent profile.