Graham-Mills
Dear Port Manager,
coins are one of the main materials that you will need on your journey. They are important in upgrading ships! Together with the ship parts, you can use them in order to build your fleet. A strong fleet, fully upgraded, is important in the competitions and in the story or event jobs. I would suggest you check THESE articles from the Game mechanics in order to learn more about game features or basic mechanics.
If you have more questions don't hesitate to ask here 🙂