SignalK Node Server Anchor Alarm Plugin
Then use WilhelmSK to set the alarm (https://itunes.apple.com/us/app/wilhelmsk/id1150499484?mt=8)
If not using WilhelmSK, you can setup the alarm using the REST API.
When you drop the anchor in the water, Call dropAnchor:
curl -X POST -H "Content-Type: application/json" -d '{}' http://localhost:3000/plugins/anchoralarm/dropAnchor
After you have let the anchor rode out, call setRadius. This will calculate and set the alarm radius.
curl -X POST -H "Content-Type: application/json" -d '{}' http://localhost:3000/plugins/anchoralarm/setRadius
You can adjust the radius (in meters) via:
curl -X POST -H "Content-Type: application/json" -d '{"radius": 30}' http://localhost:3000/plugins/anchoralarm/setRadius
When you raise the anchor, call raiseAnchor.
curl -X POST -H "Content-Type: application/json" -d '{}' http://localhost:3000/plugins/anchoralarm/raiseAnchor
If you need to set the anchor position after you have already let the rode out, it can esitmate the andchor position based on heading, depth and rode length. If "anchorDepth" is left out, then the current depthFromSurface will be used if available.
curl -X POST -H "Content-Type: application/json" -d '{"anchorDepth": 3, "rodeLength":30}' http://localhost:3000/plugins/anchoralarm/setManualAnchor