Loitering is when a single vessel exhibits behavior indicative of a potential encounter event. Loitering is estimated using automatic identification system (AIS) data, including vessel speed, duration in a given location, and distance from shore. Loitering occurs when a vessel travels at average speed of < two knots, while at least an average of 20 nautical miles from shore. To reduce noise in the carrier vessel portal, only loitering events greater than one hour are shown.
It is possible that loitering events do not indicate a potential transshipment, but another event in which a vessel may remain fairly steady, including maintenance or waiting outside of port for permission to dock.
Due to the individual definitions of loitering and encounter events, it is possible for a loitering event to overlap with encounter events and to encompass one or more encounter events.
In our map and carrier vessel portal, we focus on loitering events by carrier vessels. In the carrier vessel portal, for both encounters and loitering events, the duration can be filtered between one hour and greater than 48 hours based on your preference. This filter can enable you to restrict possible transshipment events to those you consider more likely based on duration of transshipment events.
In some specific API integrations, we send loitering events data for all vessel types. Contact [email protected] for more information.