sonar usually is used for locating objects underwater
underwater_mine_detection_device is not sonar_device. passive_sonar is not sonar_device. passive_sonar is sonar_device. sonar is navigational_instrument. find_underwater is anchor. underwater_mine_detection_device is sonar_device. find_underwater is not anchor. find_underwater is not diver. sonar_device is reconnaissance_device. find_underwater is not submarine.