The source of much of the irony in the story stems from Captain Delano’s misinterpretations of the odd situation he has encountered aboard the Spanish ship. In particular, his condescending attitude towards the enslaved people onboard prevents him from recognizing that they have revolted and are now in control of the ship and its remaining crew. In one scene that is suffused with situational irony, Delano mistakes Babo’s tight control over Benito Cereno as a form of servile affection:
Here there was a sudden fainting attack of his cough, brought on, no doubt, by his mental distress. His servant sustained him, and drawing a cordial from his pocket placed it to his lips. He a little revived. But unwilling to leave him unsupported while yet imperfectly restored, the black with one arm still encircled his master, at the same time keeping his eye fixed on his face, as if to watch for the first sign of complete restoration, or relapse, as the event might prove.
At various points in the narrative, Captain Delano misinterprets the situation on board the Spanish ship. When he first boards the San Dominick, he uses a simile that compares Babo to “a shepherd’s dog,” a characterization that is highly situationally ironic, given the true nature of Babo’s relationship to Captain Cereno:
Unlock with LitCharts A+[T]he Spanish captain, a gentlemanly, reserved-looking, and rather young man to a stranger’s eye, dressed with singular richness, but bearing plain traces of recent sleepless cares and disquietudes, stood passively by [...] By his side stood a black of small stature, in whose rude face, as occasionally, like a shepherd’s dog, he mutely turned it up into the Spaniard’s, sorrow and affection were equally blended.