What are the motifs in Ship of Fools by Katherine Anne Porter?

The portrayal of love in Ship of Fools is a pessimistic one. Many of the characters are involved in relationships that should embody love, but almost none of them have been able to attain a mutually satisfying intimate relationship. There is only one example of a love that appears happy and full of promise, and that is between the unnamed Mexican bride and groom. This couple are given no dialogue of their own; they are simply viewed from time to time strolling around the deck, obviously deeply in love.