Dead Reckoning
n. to find yourself bothered by someone’s death more than you would have expected, as if you assumed they would always be part of the landscape, like a lighthouse you could pass by for years until the night it suddenly goes dark, leaving you with one less landmark to navigate by—still able to find your bearings, but feeling all that much more adrift.
This makes sense emotionally of course, but the analogy is nonsensical. Dead reckoning is knowing your exact course and speed in relation to the land and yourself, to find out exactly where you are and where you are heading, time of arrival, etc. Having something called "dead reckoning" should not mean you feel "adrift". Quite the opposite. Someone didn't read the Chapman Guide to Piloting and Seamanship 67th edition apparently, SMH