There's more!
Achieve the standard required: "You can hack it!"
To rebrief an errant: "Hack him in the forks."
But most probably has its origins in the process of rope-making, where natural fibres are combed into straight lines by hackle-boards, which were/are blocks of wood or metal, studded with steel prongs. Hacking.
BTW. I reckon 'Mark' is so much more civilised than 'Hack' for a time check!
