Set the anchor position, then give the boat separate warning and alarm radii. The chart keeps the anchor, swing circles, current vessel position, heading, and recent track together, so a glance shows both the alarm state and how the boat has moved within it.
The watch runs aboard using the best available position source, whether that is the tablet’s GPS or data received over NMEA 2000 or NMEA 0183. Its local alarm does not depend on an internet round trip. With an always-on BoatKit device, it can continue watching when tablets and displays have been put away.
When the vessel is online, the same state is available through BoatKit Cloud and supported alerts can follow you ashore. Remote access adds another way to check the boat; it does not replace the alarm running aboard.