Know how to read Columbia River waterway markers.
Buoys depicted on marine charts are like road signs, identifying your location and the safe boundaries of the shipping channel. When moving downstream, green can-shaped buoys mark the right edge of the channel, while red cone-shaped ones mark the left. Buoys are also valuable for predicting where larger vessels will travel so you can keep clear of them.
Orange range markers on land indicate safe passage for ships and barges; two aligned markers indicate the shipping channel.