Anchor Alert is a revolutionary new electronic anchor monitoring system for motor cruisers and yachts alike. Anchor Alert uses a state of the art accelerometer, like those used to trigger air bags. This sits between the anchor and anchor chain and transmits anchor movement data to the boat via an ultrasonic wireless system. The problem with relying on a GPS to moor your boat is that if you set the coordinates too finely, it will false alarm. Set the coordinates to a larger radius, to minimise the alarms and there is a risk that you will end up on rocks.