As I never set the alarm when we are dropping the anchor – I am kind of busy with other things then 😉 – I need to set the alarm when the vessel is already at anchor.For this reason, some kind of map needs to be available to the anchor alarm, but it may all be deep blue background for all I care… 😉
This allows me to judge whether an alarm raised is because of a wind shift stronger than expected (the vessel is still on the same arc around the anchor position, just more on the edge of it than I had anticipated), or something more serious has happened (the vessel is rapidly moving away from the last partial arc that it had created on the map). I like to know the history of the vessel’s positions at anchor.For me, living at the hook, the following features of an anchor alarm app are important: These apps come in a large variety, with many different features, and so it is quite confusing which app to use. When using this app you will find that the rules of scope, like 3:1, or 5:1, are often rather poor advice! So, please do have a look and play around with the free online version.Īssuming you have done all that, it is time to set the GPS anchor alarm, i.e., to define an allowed perimeter within which the vessel must stay at anchor and finally arm the alarm. I sometimes dubb it as a preventive anchor alarm… 🙂 A free online version of this calculator with slightly reduced functionality is also available. It is described elsewhere on my home page: AnchorChainCalculator, and is available for Apple/iOS and Google/Android. For the latter, there is another app that can help you in working out the minimally required anchor chain and/or rope length and the associated anchor load. Of course, using such an anchor alarm does not mean you can neglect any of the other essential tasks and drills when anchoring, such as finding an appropriate anchorage to begin with, fit for any predicted changes in weather, making sure the anchor is properly set, and paying out enough chain and/or rode so as to reduce the anchor load to the minimal value and thus minimise the risk of dragging or worse from the start. Essentially, they raise an audio alarm when the vessel leaves a certain perimeter and thus raise your attention that the anchor may be slipping and your vessel is dragging. Here is a comprehensive feature comparison that you might find helpful.Īnchor alarm apps are a rather useful addition to increase the safety at anchor.
There are so many anchor alarm apps based on GPS available on Apple Store and Google Play Store that it becomes very tedious to compare them all.
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