by hausen » December 16, 2010, 12:50 am
Keeping the AIS's destination/ETA reading up to date is either not yet mandatory or if it is such rules aren't really yet enforced. I'm sure somewhere in some bit of regulation it might say some or all vessels are to keep the AIS as up to date as possible at all times but in my experience it's been up to the mates and/or captain to decide what that exactly means. For a vessel on a regularly scheduled weekly round trip up and down a river, for instance, it ended up being useful just to enter data for the furthest upstream and downstream points on the voyage instead of entering the ETA for each of the numerous ports/stops made by the vessel each week. On another coastal vessel with a very flexible and dynamic schedule it was essentially pointless to even bother with trying to keep updating that bit of information beyond entering in the one port every 7-10 days we knew we'd be visiting, and even then the exact ETA was sometimes an unknown factor until we were almost there.
As for lake or ocean vessels w/ respect to boatwatching; in some rare cases a lack of updates might be sheer forgetfulness, in some cases it might be that a vessel has yet to receive orders as to her next destination, or in some cases I'd imagine it might be advantageous for a vessel not to display destination and ETA too precisely in the interest of keeping private/company info. out of the hands of competitors.
For a vessel crew the safety/navigation benefits of AIS have a lot more to do with the vessel particulars and real time data about course, speed, heading, bearing, etc. than an estimated destination/ETA. After working in a given region/area for a while, any bridge personnel/watchstander will start to get a feel for what AIS destination/ETA data is decently up to date and what should be totally disregarded. Even in the best case any watchstander will understand and sympathize with fellow colleagues on another vessel regarding the fact that one of the only sureties in running a vessel is that destinations/ETAs can change at any time for a multitude of reasons.
Keeping the AIS's destination/ETA reading up to date is either not yet mandatory or if it is such rules aren't really yet enforced. I'm sure somewhere in some bit of regulation it might say some or all vessels are to keep the AIS as up to date as possible at all times but in my experience it's been up to the mates and/or captain to decide what that exactly means. For a vessel on a regularly scheduled weekly round trip up and down a river, for instance, it ended up being useful just to enter data for the furthest upstream and downstream points on the voyage instead of entering the ETA for each of the numerous ports/stops made by the vessel each week. On another coastal vessel with a very flexible and dynamic schedule it was essentially pointless to even bother with trying to keep updating that bit of information beyond entering in the one port every 7-10 days we knew we'd be visiting, and even then the exact ETA was sometimes an unknown factor until we were almost there.
As for lake or ocean vessels w/ respect to boatwatching; in some rare cases a lack of updates might be sheer forgetfulness, in some cases it might be that a vessel has yet to receive orders as to her next destination, or in some cases I'd imagine it might be advantageous for a vessel not to display destination and ETA too precisely in the interest of keeping private/company info. out of the hands of competitors.
For a vessel crew the safety/navigation benefits of AIS have a lot more to do with the vessel particulars and real time data about course, speed, heading, bearing, etc. than an estimated destination/ETA. After working in a given region/area for a while, any bridge personnel/watchstander will start to get a feel for what AIS destination/ETA data is decently up to date and what should be totally disregarded. Even in the best case any watchstander will understand and sympathize with fellow colleagues on another vessel regarding the fact that one of the only sureties in running a vessel is that destinations/ETAs can change at any time for a multitude of reasons.