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.
AIS is a cooperative maritime VHF information-sharing system for identifying and tracking ships. It enables equipped vessels and shore facilities to automatically exchange identity, position, course, speed, navigational status and other safety-related data.
Read BriefingAIS is used to identify ships, track targets, support search and rescue, and exchange safety information. As a cooperative VHF data system, equipped vessels and shore facilities automatically broadcast identity, position, course, speed, and navigational status.
Read BriefingAIS and radar can disagree because AIS position and motion come from the target's equipment while radar supplies own-ship measurements. The Automatic Identification System transmits data directly from the target’s sensors, whereas radar provides measurements relative to the vessel itself.
Read BriefingAIS matters because it makes selected vessel information available to ships and shore users, supporting situational awareness and coordination.
Read BriefingShips vanish from AIS due to range limits, terrain, lack of carriage, permitted switch-off, malfunction, or bad sensor data.
Read BriefingAIS claims are verified by cross-checking them against independent observations, primarily radar and visual evidence, to confirm accuracy.
Read BriefingAIS is a cooperative VHF system for exchanging ship data. Equipped ships and shore facilities automatically exchange identity, position, course, speed, navigational status and other safety-related information.
Read BriefingThe main limitations are incomplete carriage, switch-off, gaps, errors, manipulation, and over-reliance on AIS data.
Read BriefingYes, AIS can be spoofed through deliberate manipulation that broadcasts false identifying information or conceals a vessel’s true movement. This intentional act is distinct from ordinary equipment errors, poor transmission quality, or the legitimate disablement of units.
Read BriefingNo, it cannot identify every vessel at sea due to equipment gaps and data limitations.
Read BriefingYes, AIS can show the wrong ship position because connected sensor data may be inaccurate even when equipment integrity tests report no failure. This discrepancy arises from two primary sources: internal sensor errors and external target inaccuracies.
Read BriefingYes, 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.
Read BriefingNo, AIS does not prevent ship collisions by itself. It serves as a supplementary tool for identification and situational awareness that supports bridge judgement but never replaces visual lookout, radar plotting, or compliance with the COLREG.
Read BriefingMarine AIS typically reaches 20 to 30 nautical miles between ships, though no universal distance is guaranteed.
Read BriefingIf AIS is unavailable or wrong, use radar and visual lookout instead of relying on it. This response ensures safety by acknowledging that AIS targets may be incomplete, incorrect, or entirely missing due to equipment limitations or intentional disengagement.
Read BriefingAIS broadcasts information in three broad categories: static, dynamic and voyage-related. Shipborne AIS uses static data, dynamic data that is automatically updated by sensors apart from manually entered navigational status, and voyage-related data that is maintained manually.
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