An anchor alarm that actually wakes you

Free in Sirena Seafarer, on iPhone and Apple Watch.

Drop the anchor with one tap and set how far the boat may swing. If it drifts out of that circle, Sirena Seafarer sounds the alarm, even with the phone locked and the ringer on silent.

How it works

One tap drops the anchor at your position; drag to set the swing radius.
The alarm plays through the silent switch and keeps the screen awake while armed.
If the GPS loses the boat, it tells you instead of staying quiet.
Your Apple Watch shows the drift, for example 26 m of 40 m, and buzzes on your wrist.

Free, always

The anchor watch, the Sirena Seafarer chart, live AIS ships and the SOS position screen are free for every sailor. Premium adds satellite, TSS, NOAA and OSM charts.

A tip for the night

Plug the phone in and check the volume before you turn in: iOS does not let any app raise the volume for you.

Get Sirena Seafarer on the App Store

Sirena Seafarer is an aid to situational awareness. Use it alongside official charts and your own seamanship. Terms · Privacy