What is the main conflict in Ship Breaker by Paolo Bacigalupi?

"Ship Breaker" is a young adult novel by Paolo Bacigalupi, which details the efforts of the teenaged Nailer to secure a living for himself by scrapping ships of light metals. He comes to rescue a stranded, wealthy girl, and endeavors to bring her to safety. "Ship Breaker" thus deals with timeless themes and concepts, such as friendship, and fate and free will.