What should a vessel display if it has lost its communication capabilities?

A vessel that has lost its communication capabilities should display a distress signal indicating it is unable to communicate. This is in accordance with the International Regulations for Preventing Collisions at Sea (COLREGs), which establish guidelines for vessels in distress to communicate their situation effectively to other vessels.

Displaying a distress signal is crucial because it alerts nearby vessels and entities of the situation, enabling them to provide assistance or take appropriate action. The distress signal may take various forms, including visual signals such as flags or lights, and is internationally recognized, so other mariners understand the urgency of the circumstance.

In contrast, simply displaying a white flag or using a signaling mirror does not convey the specific message of an inability to communicate. A white flag might indicate a request for a cease of hostilities or a truce in some contexts, but it is not explicitly recognized as a distress signal. Similarly, a signaling mirror can be used for emergency signaling, but it does not serve the same purpose as a formal distress signal for lost communication. Displaying the vessel’s name and number might help identify the vessel but does not communicate the urgency of its communication failure. Thus, the choice of displaying a distress signal to indicate communication loss is the most effective action for ensuring assistance.