Regarding John Newton: "After attempting to desert, he received eight dozen lashes...".?

Just an archaic way of saying 96 lashes. Similar to Joe Bloggs will be 4 score and 10 next birthday. That's how i see it anyway.

"With heads uncovered to show respect for the law, the ship's company heard read the Article of War the offender had contravened. The prisoner was then brought forward, asked if he had anything to say in mitigation of punishment, then removed his shirt and had his hands secured to the rigging or a grating above his head. At the order "Boatswain's mate, do your duty" a sturdy seaman stepped forward with the cat -- a short rope or wooden handle, often red in colour, to which was attached nine waxed cords of equal length, each with a small knot in the end. With this the man was lashed on the bare back with a full sweep of the arm. After each dozen lashes a fresh boatswain's mate stepped forward to continue the punishment. Each blow of the cat tore back the skin and subsequent cuts bit right into the flesh so that after several dozen lashes had been inflicted the man's back resembled raw meat. After each stroke the cords were drawn through the boatswain's mates fingers to remove the clotting blood. Left-handed boatswain's mates were especially popular with sadistic captains because they would cross the cuts and so mangle the flesh even more."

For some reason, courts seem to enjoy handing out sentences in weird increments. Sometimes people get "a year and a day" in prison. Then there are the sentences of "5,873 years plus life." And of course the famous closing line of Solzhenitsyn's novel "Ivan Denisovich" about the 10-year sentence that was 3,653 days long; "the extra three days were for leap year."