According to NAUI, a repetitive dive is defined as more than one dive within a period of ______ hours.

• A. 6 hours
• B. 12 hours
• C. 48 hours
• D. 24 hours

Answer: (D)

A repetitive dive is defined by doing more than one dive within a 24-hour period. NAUI uses this 24-hour window to determine when a second dive on the same day is influenced by residual nitrogen from the first dive, affecting surface intervals and nitrogen loading calculations. Practically, if you finish a dive and then dive again before 24 hours have elapsed, that second dive is considered repetitive; if you wait longer than 24 hours, the second dive is treated as a new session with its own surface interval. The 24-hour period is the only option that aligns with this definition, whereas shorter windows would blur the boundary too much and a longer window would delay recognizing repetitive nitrogen loading within a day.