For the next part, i don't really understand it.  But, Ishmael seems to tell a story that he heard when to ships met.  they were arguing with each other about something while trying to harpoon Moby Dick at the same time.  I guess one of the guys fell in the ocean and the whale ate him.  That was just a briefing of the story, but i think it gets the point across.  Anyway,  nobody beleived the man, but he swore on his life that it was true.