Huck suffers at home from an abusive father who drinks, he is always dirty and frequent homeless. Along the story, you can notice that Huck doesn’t have social or religious values. He is skeptical of the world. Despite of that, Huck has a strong sense of right and wrong and a natural intelligence.
Jim becomes a surrogate father to Huck and takes care of him. He is a noble and loyal friend.
The raft is the ultimate symbol of freedom for Huck and Jim. When they are down the river alone on their raft they don’t have to answer to anyone.
The shore represents the rules and the society they don’t fit in, but the raft has different rules, they respect the differences between them and support one another.
The raft can be seen as a type of society that the shore can’t be, a society where one can enjoy freedom, friendship, family love and companionship, things both of them lack at the shore.