In Hardtack and Coffee, Billings described the picket rope used for artillery horses as being 75 feet long and "1-1/2 inches in diameter." (I am pretty sure this is what he said--but I loaned out my copy of the book so this is from memory. Correct me if I'm wrong!) Obviously, this is a huge rope. He may have mis-spoke and meant to say "circumference," but he seems very accurate elsewhere. If he really meant circumference this would translate to a rope about 1/2" in diameter. Also the strain 12 artillery horses can put on a rope if they got panicked is extreme. My opinion is that a properly set picket line should be about as taut and unyielding as steel cable. I have some friends who went on backcountry excursions in Africa and the picket lines were like this--very heavy and very taut. If they do yield, horses can get caught in them more easily. So maybe he was correct about the 1-1/2" diameter.
Does anyone else have on good authority what the correct measurement for picket line rope was?
10th Regt of Cavalry NYSV