When plotting a course this CLEVER NAVIGATION TOOL is a must for anyone taking a course of study which requires these kinds of calculations. After completing your course of study, keep this waterproof device on your boat. It will help in doing Fixes and LOP's which is all part of plotting a course. It's great for doing Bearings and Reciprocals. If you have a GPS aboard you can use the calculator to verify Electronic Readings . Also, on the reverse side of the calculator is a clear and simple approach to determining the conditions of Set & Drift. Plotting a course is an age old means used in boat travel. Plotting a course is essential in getting from point A to point B. When demonstrated in boating classes, over 90% of the students purchased one. They found the calculator to be practical, easy to use, accurate and inexpensive. To correct variation and deviation and to convert relative bearings to true bearings is no longer a frustrating experience. The calculator gives a clearer understanding of true north, the magnetic compass and the formula solve tvmdc, all of which makes plotting a course easier and more accurate. See testimonials. Click here for a Video Demonstration of the Calculator Comments or questions can be directed to Navigation Aid.Copyright © 2008