NavList:

Apologies if my comment below is something everybody’s already heard of (I'm new here).  I think every navigator should know something about lunars, in case the unthinkable emergency arises.

A poignant example of why is the whaleship Essex during its last, tragic voyage in 1820.  As told by Nathaniel Philbrick in his 2001 book, In the Heart of the Sea, an enraged bull sperm whale inexplicably rammed the Essex repeatedly until it sank. (This true story inspired Herman Melville to write Moby Dick.)

With the ship sinking, the sailors had the forethought to grab all the navigation equipment as they piled into three whaleboats.  This consisted of two compasses, two octants, and two copies of Bowditch, but no chronometer.  They knew their latitude, but only vaguely their longitude, and their limited food and water would not last long.  Dilemma: Which was a shorter rowing distance -- eastward to the South American coast, or west to the Marquesas or other islands in mid-Pacific?  Crucially, the Captain Pollard had NEVER LEARNED TO WORK LUNARS.  This contributed to a horrific ordeal of starvation from which only a 8 of the 20 men survived.

Roger