A helm apparatus for a marine craft or other vehicle having a steered member such as a rudder includes a mechanically rotatable steering device and a sensor which senses angular movement of the steering device when the craft is steered. A communication link to the rudder enables the helm to monitor the rudder position. A bi-directional stop mechanism is actuated when the helm determines that the rudder position is beyond starboard or port hard-over thresholds, indicating that the rudder has reached a limit of travel. The helm can cause the stop mechanism to fully engage the steering device to stop further rotation of the steering device in a first rotational direction, corresponding to rotational movement towards the limit of travel.