The ship's-wheel tattoo can be both decorative and symbolic. It can have a lot of personal meaning for the person who wears it.
On a sailing ship, the helmsman provides the direction, but not the power. Nature decides whether the wind and waves will help him on his journey. The ship's wheel can represent someone trying to find their way through the rough seas that we call "life." It reminds the wearer that we all must choose a path, right or wrong, through unseen dangers while at the mercy of mighty forces out of our control. In life, we are on a constant journey to find our way and make the most out of life's opportunities.
Thus the ship's-wheel tattoo can represent a variety of different meanings; here are some.
Navigation
Purpose
Direction
Journey
Life's path
Destiny
Opportunity
Discovery