·Hypothetical
The bonds are to hold Ulysses upright at the mast and be tightened if he begs release.
See evidence text
“bind you as you stand upright on a cross piece half way up the mast, {99} and they must lash the rope’s ends to the mast itself, that you may have the pleasure of listening. If you beg and pray the men to unloose you, then they must bind you faster”