American Practical Navigator An Epitome of Navigation Bowditch 2017 Edition Volume II As much as it is a part of history, Bowditch is not a history book. In this edition, as in past editions, dated material was dropped and new methods, technologies and techniques added to keep pace with changes in the practice of navigation. The changes are intended to ensure Bowditch remains the premier reference work for modern, practical marine navigation. This 2017 edition replaces but does not cancel former editions, which may be retained and consulted as to historical navigation methods not discussed herein. Due to critical feedback from academia, the 2017 edition reconstitutes several deleted or abridged chapters removed from the previous two editions. The additional text warranted the return of a two-volume format, with the useful tables and glossary of marine navigation located in volume II. CHAPTER 1, MATHEMATICS once again includes sections on basic arithmetic including: expressing numbers, significant digits, addition, subtraction, rounding off, reciprocals, multiplication and division. Likewise, the expanded chapter includes discussions on calculus and differential equations. Though rarely used today, an in-depth discussion on logarithms returns to this chapter. This topic is supplemented by the inclusion of haversine tables (found in Appendix B), which makes this publication perhaps the last in existence to provide this esoteric data, should the need arise to perform complex calculation manually. CHAPTER 2, INTERPOLATION includes discussion on single, double, triple and nonlinear interpolation (with Bessel's formula included). CHAPTER 3, NAVIGATIONAL ERROR was greatly expanded and updated by Johns Hopkins University-Applied Physics Laboratory. The chapter goes into greater depth on the subject than the 2002 edition. CHAPTER 4, CALCULATIONS AND CONVERSIONS summarizes the formulas the navigator depends upon during voyage planning, piloting, celestial navigation, and various related tasks. CHAPTER 5, COMPASS CONVERSIONS contains information on magnetic compass error, deviation table, applying variation and deviation, along with several example problems. CHAPTER 6, COMPASS ERROR examines the process for determining compass error using Pub No. 229 - Sight Reduction Tables for Marine Navigation.