Youth vs. experience
The narrator begins the novel by contemplating youth and the recklessness that envelops it. Youth is filled with possibilities, hopes and dreams. It is because of his youthful recklessness that the narrator decided to leave his position for apparently no reason at all. Youth makes it possible to make decisions on a whim, to follow one's inner feeling. Being put out into the world of responsibility leads to acquisition of experience, one is no longer able to make rushed decisions. Experience makes a person feel older and lose one's connection to youth. The narrator after experiencing the sea and the unpredictability of life gets this realization.
Search for one's self
The narration is filled with self-analysis and finding one's self one one's role in the world. The path to this is unpredictable and sometimes the most reckless and seemingly pointless decisions lead to one's self discovery. The narrator recklessly left his position, decided to go to the Officers' Home just because he felt like it and interrogated the Steward about letters addressed to him unintentionally. This all led him to the experience and path of his life.