What is the main purpose of a diver down flag?

• A. Indicate fishing zone
• B. Mark a diver's area and require vessels to keep distance
• C. Show no-wake zone
• D. Mark a swimming area

Answer: (B)

A diver down flag communicates that divers are in the water and nearby boats must stay well clear. The flag serves as a warning to prevent collisions or injuries, since divers may be submerged and hard to see, and the boat wake or propeller can be dangerous to them. In most places, boats are required to keep a safe distance—often about 100 feet (30 meters)—from the flag and any diving activity.

This isn’t about marking fishing zones, no-wake zones, or swimming areas. Those needs are indicated by different signs or markers, whereas the diver down flag specifically signals diving operations and the need for other vessels to maintain a safe distance.