Most chartplotters include an anchor alarm to alert you if your anchored boat moves too far from the anchor's position, indicating that the anchor may be dragging - a critical tool for getting a good night's sleep! For boaters lacking this functionality, several apps are available for GPS-equipped smartphones and tablets. I've just concluded testing two popular anchoring apps, DragQueen Anchor Alarm and My Anchor Alarm, with a close look at the differences. What about you - have you used one of these apps or a different one? Share your experience with a comment here for other boaters.