Assertion: rudder | /r/HasProperty | mechanism
Facets:
value: for steering boats
type: PURPOSE
Source sentences:
text: A rudder is a mechanism used to steer a boat, airplane, ship, hovercraft, or submarine.
text: A rudder is a mechanism for steering boats which evolved from the "steer board" (whence "starboard"), later the terminology was transferred to aeroplanes, hovercraft etc for the vertical, pivoting section of the tailplane (which is not the primary means of changing direction, unlike on a boat.)