On the bridge

At any given time, there is at least two officers and one sailor (who keeps a visual look out) on the bridge.

When there is heavy traffic, bad weather, or coming into port, they have six on the bridge.

To change the course, it takes the approval of two officers and then final approval by the Master.  At various points, they also have a pilot captain who comes aboard in an advisory position because s/he knows the area very well.