What should you do if you see a vessel displaying a gray flag?

When you see a vessel displaying a gray flag, it indicates that the vessel is involved in a dive operation or is conducting underwater activities. This flag serves as a warning to nearby boaters to be cautious and aware of potential divers in the water.

Choosing to slow down and proceed with caution is the appropriate reaction in this situation. By doing so, you minimize the risk of an accident or injury to the divers while also ensuring that you maintain control of your vessel. This cautious approach allows you to observe the area and react if necessary, as well as to ensure the safety of those who may be submerged.

Maintaining speed and continuing on your course may lead to dangerous situations if divers are present, while signaling back with a whistle or changing your course immediately could either confuse the other vessel or potentially lead to unforeseen hazards. Slowing down and being vigilant is a responsible and prudent choice when you encounter a gray flag.