Errata for Emergency Navigation, 2nd edition

Page 132. The first sentence of Chapter 10 is not right. It reads: "The word 'dead' in dead reckoning derives from the abbreviation 'ded' for deduced." After some study, we have concluded that that statement is not true. This seemed a reasonable interpretation at the time we wrote it (early 80s), since we see the DR position listed as "ded." in many 19th century logbooks, and indeed this is the word origin presented in several prominent texts including Dutton's and early editions of the British Admiralty Manual of Navigation, as well as in several other texts, less well known. The Bowditch origin of the term is also wrong, but for other reasons. We will present shortly the results of our study on the history of the term dead reckoning.

Page 251. Bibliography, almanac Data, website for George Bennett is incomplete, should read

Page 163. Bottom graphic has two stars misnamed. The one the editor's graphics staff changed to Rigel is actually Betelgeuse and the one they called Saiph is Rigel. The top part is correct.

Page 158. Figure 11-8. Inset angles are minutes of arc, not degrees as shown. Also, the error interpolated from the figure is 18', not 21' as stated in the text on page 158 and repeated on page 159. Thus the Lat found is 10° 16' + 18' = 10° 34' N, not the 10 37 shown. .... also, the scale should span to 40' not 42'. This reflects the motion of the so called "fixed stars" over 30 years or so... actually precession of the earth's axis, but sort of the same effect. 

Page 46. Caption to fig 5-4. The editors added the sentence beginning "Southern stars .... ; northern stars are...." this is wrong. Ignore that sentence and just look at the pictures.

Page 53. Figure 5-19. Again the publishers's contracted graphics helper for some reason inserted a star name that was not in our original. "Gienah." We did not have any star named there, and in fact the star called Gienah is Albireo. (Thanks to DL for pointing this out.)

Page 122. Caption. It says: start by looking in the opposite direction you think the sun bears.... this is true only before the sun sets, when it is still some angle above the horizon, and that is the example that is discussed. However, once the sun sets, then 90° from sun direction, is still in the direction of the sun, so that statement was too general. In the long run, this method works best when the sun is low, down to within some +30 to -7° of the horizon. So the really short answer is, you look up. If it has not set, it is up and back; if already set, it is up and somewhat forward toward the general direction where you think it set. This is not an editor's fault, it was ours. Here is a video illustrating the process.

Page 228. 2nd paragraph.  100-15 = 85W, not the 75W listed. (Thanks to Dr. Steven Henkind for pointing out this error and the next one).

Page 211. Bottom paragraph. "less than 15º" should be "less than 30º". (The approximation refers to half the full angle referred to in the text and we misquoted this.)