Yachting Magazine: "probably the best dollar youve ever spent" Description: "Anchor Watch" uses the GPS on your smartphone to monitor your boats position. If the boat moves outside of set limits, the program will alert you immediately. Alerts include phone calls, sound, vibration alerts, popups, email or SMS (through a third party). There are no more sleepless nights when you worry about weather your boat is dragging or not. Keep the phone next to where you are sleeping and a quick glance will assure you that all is ok. If the boat drags out of the predefined area (no limit on radius), it will alert you in any way you decide. Flashing text, sounding alarm or even call to another phone. As only anchor guard app for iOS, Anchor Watch allows for the manual adjustment of your anchor position, by touch of a finger or manual entry. So if you were busy with other things then setting the alarm, you can adjust for the drift. And if you anchored both stern and bow, Anchor Watch offers an unique course alert when a minor drift can still mean your boat is turned from the pier. Anchor Watch sophisticated filtering allows for GPS errors, which can occur every now and then. The settings panel is fully customized allowing a number of different alarm types. Of course it runs in the background too, which allows you to pursue other activities on your phone while Anchor Watch is on guard. Continued use of GPS running in the background can dramatically decrease battery life. Fortunately you can tell Anchor Watch to conserve battery and update only in foreground. Available as an in-app purchase are advanced nautical maps as well as the functionality to download and show offline maps which you can use when you dont have a data connection (or dont want to use it due to roaming charges. The maps available are based on the http://www.openseamap.org data. Check for quality and availability on their website, it is under rapid community development. You can also send in your maps and they will be added to the server for the benefit of all. Anchor Watch is under constant development, so if you have any remarks just drop an email or write a feature request in the comment section and we will get straight to it. Known issue: enable Alerts in iPhone->Settings->Notifications to receive audio alerts in the background