Don't know how many boaters we have here. But I would assume a few. When sleeping on my boat, anchored out somewhere, it would be nice if my phone could sound an alarm if it notices my anchor has come loose and I'm drifting. So I set it, and if I move say, 50 yards (or whatever value I set , the alarm would go off and let me know (or wake me up). I haven't found anything like this in the app market. So I guess my question is, is there any other app, intended for some other use, that would accomplish this? (There is one for the iPhone, so I know it can be done, and there's a need.)