In the CPA – Closest Point of Approach lesson we discussed general plotting concepts of another vessel’s relative movement using Distance and Bearing along various time intervals to derive a solution as to how close the other vessel will approach if your course and speed and their course and speed remain unchanged. The example used developed an RML between “you” and vessel “M” of 081R, with a CPA of 2 miles at 352R. TCPA was found to be 0948, 48 minutes after point of first contact. Obviously, there is no risk of collision in this case, however, some additional information may be developed that will be useful. Related Pages Closest…

Maneuvering Board Layout The maneuvering board (aka mo board) is a diagram used in the solution of relative motion problems. In marine navigation there are several “problems” involving the use of relative vectors. As it pertains to marine navigation, relative vectors contain two factors, speed and direction. Common problems encountered in navigation that are greatly simplified by the use of a mo board include: While all relative vector problems are plotted basically the same way, each problem has its own specific requirements such as labels. Therefore, each of these are discussed in full in individual lessons dedicated to the topics. Parts of the Maneuvering Board There are three main “parts”…

Why? The question of why use radar comes up often. Over the years, I have had a number of students who felt radar was outdated and of limited use in todays world of GPS, Chart Plotters, and AIS. Sadly, this could not be further from the truth. One important point about radar’s value is its ability to tell at a glance how close you are to being on a collision course with an object. Whether another vessel, a buoy, or a rock, radar provides visual evidence of a target’s track in relation to you. Some simple plotting provides information about how close you will pass and how long you have…