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.
While the watch is active, an anchoring worksheet combines the adjusted depth below the waterline, the largest additional tide rise expected over the next 24 hours, and the rode exit height. It shows 3:1, 5:1, and 7:1 scope references. A separate rough catenary-based chain-length check uses chart depth at the anchor, a dedicated bow sprit height, and the bow center’s live distance from it. Per-GPS antenna positions let BoatKit derive that bow point, while the tide-rise value centers and opens the selected tide station directly on the chart. These are planning aids—the catenary estimate does not model chain weight, seabed, wind, current, snubbers, or the amount actually deployed.
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.