Yes, a ship can switch off its Automatic Identification System (AIS) under specific safety or security conditions. While equipment can be turned off, international guidelines require it to operate normally unless continual use compromises safety or security. A master may deactivate the system if a security incident is imminent, provided the action and reason are reported and recorded in the logbook. Operation must resume once the danger has passed. Not all ships carry AIS, and fitted units may be switched off in these limited circumstances. Consequently, received data may be incomplete, unavailable, or wrong. The loss of reports does not prove intent to deceive; it simply reflects a temporary cessation due to valid operational reasons. Furthermore, AIS does not prevent collisions by itself and does not replace visual lookout, radar plotting, use of all available means, or compliance with the COLREGs.
