Chapter 4 of Billy Budd is a digression from the main narrative of the novel, something the narrator acknowledges at the start of the chapter. The narrator mentions that it is acceptable to hold both the advances of present times (or the time of the novel's narrative) in esteem while also appreciating the past.

In this chapter, the narrator discusses Admiral Horatio Nelson and the Battle of Trafalgar which occurred in 1805. The narrator discusses Admiral Nelson's choice to wear his dress uniform and all his many medals during the battle. This made him a target of enemy sharp-shooters and caused his death. Some people say he might have survived the battle if he chose not to draw such attention to himself. The narrator dismisses this line of thinking as being built on "boggy ground." The narrator points out that Admiral Nelson's fame comes from his brashness and pride, even though it led to his death.

Melville includes this digression about Admiral Nelson to describe his view of the model sailor. Admiral Nelson was awarded many medals and gave his life in service of this country. Nelson's pride is not a fault, according to Melville, but something to be admired and emulated. When Captain Vere is introduced in Chapter 6, the reader is meant to draw instantaneous comparisons between him and Admiral Nelson.

The chapter is about Lord Nelson and his death at Trafalgar. Melville writes about the story of how Nelson chose to wear all his military decorations on his coat in battle, making him easily identifiable to enemy marksmen. Some have suggested that Nelson’s death was a result of vanity. Melville’s point is that Nelson was right to do so, from a poetic point of view. His choice to “dress his person in the jewelled vouchers of his own shining deeds” arose not from “foolhardiness” but from his identity as a true hero, equal to Achilles or Ulysses or any hero from the “great epics.”

This digression is meant to be a gloss on the beauty of Billy Budd. Melville is implicitly comparing the “handsome sailor” (Budd) with the “great sailor” (Nelson). In the same way that Nelson could not help but wear his honors into battle, Billy cannot suppress his natural nobility and beauty.