Reciprocal Course Navigation (RCN) is a navigational method used by ships and submarines to maintain a safe and timely course. It works by accessing the course that both the ship and its destination are on, and then adjusting their own course accordingly to ensure that their destination is reached in the most efficient and safe manner. This method of navigation involves the consideration of multiple variables, including wind, currents, and visibility conditions. When navigating with RCN, a ship or submarine plots a course toward its destination on a chart. As it begins to travel, both the ship and the destination continue to adjust their courses in relation to each other in order to stay on track. For instance, if the wind and current have come up, the ship can adjust its course to take this into account, while the destination may also adjust in order to make up any lost time. When the ships track each other in this way, they are able to reach their destinations safely and on time. RCN is a very useful navigational tool, especially when travelling in unfamiliar waters. It is useful in areas with unpredictable currents and winds, such as the open oceans. By using RCN, ships can safely plot a course and adjust it accordingly in order to avoid dangerous areas or environmental conditions. Because the method is easy to use and understand, it is often preferred by maritime operators over more complex navigational methods.