Christianity
The character of Attwater is the only one who is religious in the book, until he converts Davis at the end. Attwater is not a kind man. He's imposing, judgemental, and angry. According to his religious beliefs, he behaves as if he has divine authority to judge all the people whom he encounters. This is why he is not a friend to the beached ship. His religious beliefs instill in him a great deal of moral superiority so that he believes he is truly a better person that the other characters. Because of this, instead of killing Davis when he has the opportunity, he spares him and quotes Jesus. Essentially, Attwater is playing God. He thinks that because of his faith he possesses the authority to determine even who lives and who dies. When his life is spared, Davis converts to Christianity as well. For whatever reason, he is consumed by this faith, to the point of mania. He will rest at nothing until Herrick also converts. This is the ultimate satisfaction and confirmation for Attwater, completing his belief that he is in fact a superior being.
Greed
Huir, Davis, and Herrick all have fallen on hard times and lead fairly destitute lifestyles. They are desperate men, dead set upon changing their life circumstances. Both Davis and Herrick used to be prosperous and successful men, so they are trying to regain what they formerly had. On the other hand, Huir is a crook and a tramp, never settling on any certain lifestyle. The three of them set off on the ship because they intend to double cross the crew and sail to Peru and sell all the cargo and the ship itself. They don't care about the crew or their contracts. They are blinded by greed and determined to start their lives over somewhere new. When mother nature doesn't cooperate, they change their plans. Attwater becomes their next as they try to steal his pearls. Herrick is convicted of his wrongdoing and tries to kill himself. This doesn't stop the other two, however, and they try to murder Attwater for his pearls. They are again frustrated, their greed accomplishing nothing in the end.
Betrayal
Motivated by greed, Huir, Davis, and Herrick only accept their positions on-board the ship in order to double cross the crew and attain their own gains in Peru. They are dishonest men with no honorable intentions. Even during the voyage, Huir and Davis remain constantly intoxicated, drinking away profits that aren't theirs. Then they discover that the former captain of the ship had betrayed his employers by exchanging half of the champagne cargo with water. He had planned to commit insurance fraud and sink the ship when the smallpox broke out on-board. When they encounter Attwater on his island, instead of being grateful for his goodwill and aid, they immediately plot to steal from him. They deliberately lie to him, even trying to kill him. Among the threesome, Herrick cannot even remain loyal to his own conspirators. He is consumed by guilt and betrays them to Attwater.
Fate
The three main characters experience a lot of strange twists of fate over the course of this novel. To begin with, Davis is given the perfect opportunity when the champagne ship pulls into port. Having failed his last voyage and lost his ship, he is unable to work as a sea-captain any longer. Consequently, he is the only one willing to risk the smallpox by commanding the desperate ship on its journey to Sydney. During the trip, however, the three men are shocked to discover that the former captain had intended to sink the ship and commit insurance fraud before he died of smallpox. Fate interceded in his scheme and killed him of the disease before he was able to follow through with the scheme. Apparently, Davis, Huir, and Herrick don't take heed of the captain's fate because they immediately decide to screw over Attwater and steal his pearls. They play nicely with him, all the while waiting for the opportunity to rob him. Attwater is too observant to be cheated, however, and sees through them. No matter the scheme, the three men are not allowed to be successful. Fate dictates that they will be rewarded for their deviancy. In the end, Davis decides to convert to Christianity in an attempt to take control of his own destiny by aligning himself with a higher power.
