Your assessment of the necessity of maps at sea are totally incorrect. Accurate maps are vital to the lives of the crew, the ship, and the cargo. The trip from Shanghai, China to Long Beach, CA is more than 6000 miles. You can have countless storms along the way that need to be avoided when possible. It can be cloudy or foggy and you can't see any stars for a week at a time. Often it is necessary to alter course to avoid a known storm that is visible on the satellite maps we get on a daily basis. Do you really think that we turn left at the next wave and go 100 miles until we see a mermaid pointing us in the right direction? Usually a container ship will carry 100's of millions of dollars worth of cargo. Many shippers have their own trackers on top of the containers that can monitor the ship's progress. They will immediately know if the ship has an incompetent navigation officer. You can be sure that very little is left to chance. There is a detailed voyage plan made out and check lists completed before the ship ever leaves the dock. The trip is long, the weather can be bad, and very good detailed charts are vital to our very survival. Our charts allow us to navigate a distance about the same as from going from New York to Los Angles and back again without ever seeing any kind of landmark and arrive at our destination safely and on time.