Hello! I previously had a number of boats running prior versions of Ardurover that could use the sonar as a range finder to avoid running aground as described here: https://ardupilot.org/rover/docs/rover-object-avoidance.html
However, 4.0 doesn’t seem to support this; I’ve tried bendy ruler but cannot seem to get it to work with a downward facing sonar. It does not react to shallower depths. Does anyone have any input? Is this possible or perhaps am I making a configuration mistake somewhere?