I've tried a bunch of Android apps, and even my regular
chartplotter. I haven't done a scientific study; I just try out different stuff as the mood strikes me.
I ended up deleting Drag Queen and Sail Safe. Not that they were bad, just that I didn't take to them well. Anchor Lite and "AchorWatch" by Jos Verbeek are still on my
phone and used occasionally.
But far more often, I just use a regular
navigation app (usually MX Mariner or
Navionics, but any one will do) and zoom in as far as I can. This gives me a "track" over time. If it looks like a nice fuzzy
arc around a central point, I'm good. When it strikes off in a new direction, time to get worried.
Changes in
wind strength or direction, even swings in heading, tend to wake me up pretty easily at anchor. I only set an
alarm if I'm not confident in my set or if I expect a change in
weather or
current.
Proximity of rocks would be another reason to set an
alarm, but it's hard to set an alarm that would give me enough warning before hitting them. I've forgotten to turn the alarm off, and I'm usually well past the rocks when it finally goes off on my way out of the anchorage the next morning. In other words, it would have been much too late.
I do have a Vesper XB-8000 but haven't really played with the anchor alarm yet. I like the implementation, just haven't been in a situation where I felt like setting it up (and leaving the
AIS on all night.) My phone is always plugged in and displaying the chart overnight anyway.