Nation (novel)
Mau had been on a trip to the Boys' Island to become a man.  In the Nation, boys go to the island for thirty days to live alone.  When they come back, they are given a ceremony that makes them men.  The ceremony has a feast, tattoos, and ritual circumcision.  The boy is supposed to leave his "boy's soul" on the boy's island, sail home, and then get a "man's soul" after his feast.