In which situations should a mayday call be initiated?

A mayday call is used in situations of grave and imminent danger requiring immediate assistance. This type of distress signal is appropriate when a vessel is facing life-threatening circumstances, such as a mob, fire onboard, or when there is a risk of dangerous grounding. Each of these scenarios represents a critical situation where the safety of individuals and the vessel itself is at high risk, making it essential to alert nearby vessels and emergency services for immediate help.

In contrast, minor accidents do not typically warrant a mayday call as they do not pose an immediate danger to life or the vessel. Likewise, while navigation assistance can be important, it doesn’t signify an emergency; therefore, it is not a reason to initiate a mayday. Mechanical issues can range from minor to severe, but unless they directly lead to imminent danger, they would require a different means of communication, such as a "Pan-Pan" call for urgency rather than an outright mayday. Thus, a mayday call should be reserved strictly for critical, life-threatening emergencies.