Questions

[pabrides]

Thanks for telling us about the updated Bowditch.  

 Distance = 90 – Sin -1 (sin(Destination latitude) x sin(Your present latitude) + cos(Destination latitude) x cos(Your
present latitude) x cos(Difference in longitude between Your Location and Destination Location)
 
 As to electronics.  Ugh, yesterday I was trying to tighten a bolt on the boat trailer hitch and needed the ol' trusty flashlight.  Would the batteries work?!  Of course not!  I was "on the hard" but was a' cussin' like a sailor.

Lou

I thought perhaps 2017 Bowditch might be old news.... your welcome

Your formula seems similar to the one for finding Hc.  Ill try it for fun, but I still want to learn the haversin table as well as all the nav tables no longer popular.

As a side note; last week one of my English students volunteered to work long (5 significant digit) math problems by hand while I used the log tables.  I consistently worked the problems in half the time with fewer errors.  The log tables work well.

I read that with distances of <600 miles the difference between the great circle and mercator is insignificant, and even at the longest distances the difference is still only about 4 percent; which might be significant in aviation terms, but to ships at sea very little. 

I laughed at your loose bolt experience; "...cussin like a sailor." 

While in the Navy, especially at sea, I always carried a flashlight on my hip in a Velcro loop holster for emergencies - and I made triple sure it was working (the idea of being caught below decks in a darkened ship scared the bejeezes out of me).  Nevertheless, I went to use the flashlight in my tool box a month ago and it was flat dead... I still haven't replaced the batteries..  Its funny how our priorities change.

joe