Our Daily Bread (Verbal Irony)
One of the sailors sees the words "Give us this day our daily bread" inscribed on a plate he is cleaning on the ship. This reference to a biblical compact flies in the face of the treatment of the sailors; they have not even been given the basic standards of food to which they should be entitled. The language on the plate contrasts with the reality that, on the plate itself, the sailors won't be given their "daily bread."
Rifles (Situational irony)
The Commander orders the guards to kill the dissenting sailors by firing their rifles. He thinks that these men are under his control, and that the firepower will keep the sailors in line. However, they don't fire because they know what they are doing is wrong. Now the commanding officers are outnumbered and outgunned by the men and get run over. The guns that Golikov believed would give him power become, instead, his undoing.