This simple graphic shows how simple Secondary Port Calculations can be to learn, the A4 encapsulated sheet will make life so much easier.
Side one explains how the information that you need is laid out and what that information means. It then shows a worked example of Time Differences and side two has a worked example of Height Differences. Side two contains plenty of space for your own calculations.
Matt encapsulation means that a 2B pencil can be used directly on the plastic.
