I used to live in Portland, Oregon. I spent a lot of time on the coast. One weekend I decided I wanted to learn more about the ships coming and leaving out of Portland and I had heard the Columbia River was one of the most dangerous for ships to navigate due to the high sand bars. Astoria is the main place ships have to wait for someone to help them navigate the ocean and Columbia River bars. There are bar pilots there and each ship requires two: one to help navigate the ocean into the Columbia, and one to navigate them up the Columbia.