Anchor alarm
Most anchor alarm apps watch one thing: a circle around your phone. Cloud Shelter's Anchor Watch reads the boat's own GPS and wind through the NMEA 2000 gateway, watches four things at once, and sounds the Lookout siren aboard while sending the alert to your phone.
You drop the hook, arm the watch from the boat's page, and it holds that position as the anchor until you weigh anchor.
Drift from the anchor: an alarm if the boat leaves its swing circle, from 15 to 150 metres (40 m by default). Moved right off: a separate alarm if the boat is suddenly far from the anchorage — broke free, towed or taken — from a quarter of a nautical mile to five.
Wind speed: an alarm when it blows harder than your limit. Wind backs or veers: an alarm when the wind swings onto a new quarter — the one that turns a safe shore into a lee shore.
At anchor a boat lies head to wind, so its compass heading tells you where the wind is coming from. Cloud Shelter records the heading when you anchor and alarms on a change past your limit. In light air a boat swings with the current instead, so the wind-direction watch only acts when there is enough breeze to hold the bow — no false lee-shore alarms on a calm night.
On a trip the Lookout hub sounds its siren on board and a Telegram alert goes to your phone. Silence it from Telegram and it stays quiet for that alarm; a new kind of alarm still sounds. Without a Lookout aboard, you still get the phone alert.
When you weigh anchor and motor away, the watch stands itself down, so leaving never sets it off — it waits for two consistent readings, so a single noisy GPS sample cannot switch it off. If the GPS fix is lost for more than a minute, it tells you it cannot see rather than failing quietly.
Drop the hook, let the boat settle on its rode, then open the boat's Anchor Watch tab and arm it. The watch takes the boat's current GPS position as the anchor and its compass heading as the wind baseline. If you re-anchor, 'Set here again' moves the anchor point to where the boat is now. Each watch has its own switch and limit, and the whole page — chart, distance from the anchor, wind and heading — updates live while you are ashore.
A dropdown shows exactly what the watch is reading off the NMEA 2000 bus, what it works out from it, and the decision each watch is making right now, so you can see why it is quiet — or why it is not.
What it needs: a boat position source — the Cloud Shelter NMEA 2000 gateway or a Victron Cerbo GX — and an internet connection aboard (marina Wi-Fi, 4G or Starlink), because the watch runs in the portal. The wind-direction watch also needs a wind instrument and a heading sensor on the bus.
An app watches the phone in your pocket, so it only works if the phone stays aboard and awake. Anchor Watch reads the boat's own GPS and wind, sounds a siren aboard and alerts your phone wherever you are.
No. When the boat is clearly under way on two consecutive readings, the watch stands down and tells you so.
The watch runs in the Cloud Shelter portal, so the boat needs a connection — marina Wi-Fi, 4G/LTE or Starlink — for the alarm to reach you.
Start at the default 40 m and adjust to your scope and the anchorage. The swing circle can be set from 15 to 150 metres.
Not for the phone alert. The Lookout adds the siren aboard. Without one, the alarm still reaches your phone on Telegram.
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