What does the ship symbolize in the book Lord of the Flies?

The ship that the children see in the William Golding
novel Lord of the Flies symbolizes at least two different things.
First, it symbolizes survival. A ship would be the boys' only way off the island, so it
is important that the boys keep a signal fire burning at all times as a marker in hopes
of rescue. Secondly, the ship symbolizes the outside world, the civilized world to which
the boys hope to eventually return. It also serves as a reminder of the war that is
going on outside the boys' island world.