Anchor!'s Manual

Main view

This is the position of your anchor on the Map.

Anchor location

Anchor features the unique possibility of moving the anchor position. Make a long press and drag the anchor where you need it.

You don't need to stand on the windlass and push a button while anchoring. Set the anchor later, this page explains how to put it in the right place.

Alarm distance

The alarm range can be set on the map or in the settings. The alarm will be triggered when the boat exceeds this distance from the anchor.

Chain length is not a sufficient distance, see this page to get the right distance.

Arc perimeter (IOS only)

Each red disk sets its side of the arc. The arc opening must be at least 25° because the app would not work well with smaller arcs.

Read the consequences of accuracy on custom shapes.


The path of the boat is shown on the map. The color of the path slowly evolves with time to allow you to discriminate older locations. If the anchor holds correctly, the most recent tracks will be above the older ones.

Auto zoom

The application automatically set the zoom level when you center on the anchor according to the alarm radius.

Start monitoring

Use the LOWER button to set the anchor position in the current location and and enable the app.

Stop monitoring

Use the RAISE button to disable all alarms and before lowering again: The adequate moment to push the RAISE button is while raising the anchor or whenever you want to disable the app.

Find your position

The locate button enables Tracking mode: the map is centered on the current location and follows the device. When Tracking mode is enabled, the icon gets blue.

Tracking mode can be disabled either by deselecting the locate button or by moving the map.

Get back to your anchor

The anchor center button centers the map on the anchor location and adapts the zoom.

Cancel a movement (IOS only)

Revert to previous anchor location.



When an alarm is triggered, you will be prompted to stop the alarm for 15s. You can then disable the alarms, change the alarm radius or the anchor position as you see more fit. After 15s, the alarm will run again if it is enabled and triggered.

To prevent spurious alarms while you are setting your perimeter, some actions resets the snooze times.

Alarms channels

Alarms channels are in the top right of the screen.

You can enable any of the alarm channel independently. Disabled alarm channels are crossed out when the alarm is off.

The raise button disables all alarm channels.

Ring alarm

The main alarm channel will make an alarm sound.

Blink alarm

The visual warning is blinking to attract attention.

Visual warning is effective only when the app is running in foreground.

Mail alert

Get alerted by email (Internet connexion required).

Enter your email and send a test message. Check that it is not classified as spam. If it is, please bring it back to inbox and add the sender ( to your contacts.

SMS alert (Android only)

Get alerted by SMS (Cellular connexion required).

The quantity of SMS to be sent is limited, the remaining number of SMS to send is displayed. You can adjust this quantity in settings.

IOS apps are not allowed (by Apple) to send a SMS from the telephone.

Some app send SMS through a server, which requires internet connexion: if you have internet connexion the remote mode offer a much better service than the sms alert.

Remote mode

Anchor! must be running on both devices

The monitored (sending) device must invite monitoring devices, the invite can be done by mail or Airdrop (IOS only).

Each position is protected by a password, the monitoring devices needs the password set on the monitored device to access the last position.

Sending (arrow up) posts periodically your location to our server. The server only keeps the last location.

Receiving (arrow down) will pull the last location from the server and alert you - when appropriate - using any enabled channel (Ring, Blink, and even mail and SMS).

It is recommended to keep Anchor in the foreground while using this function

It is advised to always have someone on board of the anchored boat to watch your anchorage and take action in case it does not hold.


Maps and Units

Change to satellite view and choose your preferred units.


  • Enable and disable tracking

  • Clear the track

  • Adjust track recording

  • (IOS only) export the track.


Set up, enable, disable and test alerts.

False alarm filter

To limit the number of false alarms, you might want to enable 'Filter Alerts' in settings. The alarm will be raised only if:

  • it is still valid after 5 positions


  • the speed of the boat is not unlikely (less than 15 kts)

GPS fixes are filtered according to their accuracy. All positions too inaccurate are discarded, you can set the threshold.


Battery usage

This application require precision positioning. Precision positioning drains the battery quickly. Once in background, the localisation is stopped if no anchor is set. However when an alarm is active, even in background Anchor! will track your position to notify you if you leave the anchor perimeter. If you intend to use the app for a long time, put your device on charge.


It is recommended to launch the app a few minutes before anchoring, so that the accuracy builds up.

Read how GPS accuracy impacts your app


The app use the maps provided with IOS (IOS) or Google (Android). These maps are not nautical charts: do not rely on them for navigation. Check reliable charts for depth contours while anchoring.

Read how GPS accuracy impacts your app

Contact us

Whether you need help, would like to suggest a feature or report a bug, do not hesitate to contact us.

Please prefer the in app contact us form (in settings) to get a quicker and more appropriate answer.

Table of contents