canal lock: side view![click to hear](/images/speaker.jpg)
upper gate ![click to hear](/images/speaker.jpg)
Watertight door or pair of doors made of wood or metal that open when the water levels between the lock-chamber and the upper level are the same.
lower gate ![click to hear](/images/speaker.jpg)
Watertight door or pair of doors made of wood or metal that open when the water levels between the lock-chamber and the lower level are the same.
upper level ![click to hear](/images/speaker.jpg)
Part of the lock at the upstream end of the lock-chamber.
lock-chamber ![click to hear](/images/speaker.jpg)
Central part of the lock where the water level is raised and lowered depending on the heading of the ship.
lower level ![click to hear](/images/speaker.jpg)
Part of the lock at the downstream end of the lock-chamber.
flow ![click to hear](/images/speaker.jpg)
Natural current moving down the grade from upstream to downstream.