Abstract: A method and device for controlling movement of a moored boat employs a boat mooring device comprising a base to be anchored to a pier or float and an upright stem, a helical spring, and a connecting arm having a distal end equipped to be connected to an attachment point on a boat to limit movement of the boat relative to the pier or float. The spring is elastically stretchable to urge the boat toward the pier or float, or bendable into a gooseneck configuration to urge the boat away from the pier or float, in response to the influences of waves or wind. The same spring also automatically retracts the connecting arm into an upright condition when the mooring device is not in use so that it does not present an obstacle to docking the boat.