This statement means that if you are doing what you want to do and being who you want to be, then there is no need for a physical ship or any other external factors. You are in control of your own life and destiny.
Ten reasons why this is true:
1. You are the captain of your own ship.
2. You decide where your ship goes.
3. You are the only one who can steer your ship in the right direction.
4. You are the only one who can set the course of your ship.
5. You are the only one who can choose the destination of your ship.
6. You are the only one who can determine the speed of your ship.
7. You are the only one who can choose when to set sail.
8. You are the only one who can choose when to stop sailing.
9. You are the only one who can change the course of your ship.
10. You are the only one who can choose to disembark from your ship.