No matter how sophisticated our navigation electronics might be, safe navigation at night boils down to keeping track visually of where you are relative to navigation lights—on buoys, lighthouses, or posts in the water.
Recall that the lookout, Maureen Jones, warned the third mate in charge of the Exxon Valdez that the crucial Bligh Reef Light was on the wrong side of the bow as they sailed forward, onto the rocks. In fact she warned him twice. [*]
Efficiency is also at stake when you have limited navigation aids on the boat or aids to navigation on the waterway. You might turn into the wrong channel or miss the one you want if you misjudge when certain lights should or should not be visible.
We have more in-depth treatments of this important topic in the book Inland and Coastal Navigation, but we present here the short version that we prepared for the R2AK team for a quick review, which accounts for examples from Canadian waters.