Plotting contacts is all a matter of references. Where you physically are on the map is not important, where you physically are when you start to plot is important. Placing a mark on the map at the time you take a stadimeter reading will help you plot contacts. Pick a place, it doesn't matter, place an X. Take a stadimeter reading. Note the bearing to contact. Draw a line through your X heading in your sub's current course. From that X and using the line through that X as a reference draw an angle that is the contact's bearing. Measure out on that bearing line to the stadimeter distance you found. You now have a general idea of where the contact is in relation to you. Keep track of time between contact map updates so you know how far you travelled so you know where to place your next X on your course line from the last X. Keep repeating process till you have a firing solution
