I think one of the central ways that this chapter points towards the development of Pi as a character is the way in which Pi reacts to Richard Parker once the tanker has passed them by and disappears over the horizon. Clearly Pi is very emotionally wound up by the way that he has missed out on being saved. However, when the tanker disappears, he looks over at Richard Parker and sees that the only thing he is aware of is that he is somewhat upset or agitated. Pi's response is very interesting. Note what he says in the quote that ends the chapter:
"I love you!" The words burst out pure and unfettered, infinite. The feeling flooded my chest. "Truly I do. I love you, Richard Parker. If I didn't have you now, I don't know what I would do. I don't think I would make it. No, I wouldn't. I would die of hopelessness. Don't give up, Richard Parker, don't give up. I'll get you to land, I promise, I promise!"
The arrival and departure of the tanker and the way that it represents a hope of salvation that is cruelly dashed thus forces Pi to realise how important his relationship with Richard Parker has become to him, and how, in a sense, he is a part of himself.