Mercator Sailing: Course and Distance

[Gene222]

Okay. You convinced me. I will use your ATANH formula (the first one). The formula really does need to be accurate to transition to the formula for the East-West course. I think I got the program just about done, but I need to recheck it to see if I got the signage right for all cases. I got hung up on the 0 and 180 degree meridian crossings. Attached are the Mercator Sailing signage rules that were not included in the Calculator AFloat book.

EDIT 11/9/18. The following is from The Yachtsman’s Handybook by WH Rosser, Charles Wilson Publisher, 1877, Brief Rules In Navigation Chapter, 6: Course and Distance by Mercator’s Sailing Section.