Harbours are built by Miniconomy Ventures. You do not require a harbour to buy and sail with ships.
Building a harbour
A harbour must be built on a lot next to a road the water. Check the map to be sure that the lot meets both conditions. When the harbour is built, it becomes visible in the street. You need quite an amount of money to build a harbour as you need:
Making money from a harbour
There are two ways to make money from a harbour. The first way does not require any skills and is done by setting harbour fees ship owners need to pay for sailing to this harbour. The second option is building ships. This second option is very costly and is most often done on demand. The production costs of ship building can be reduced by setting skills. After building a ship, it will automatically be placed in your wharf as long as you entered a selling price. Other players can then buy these ships.
Harbour Manager
You can access the manager of the wharf of your harbour by going to the harbour via the My Property page in the left menu. In the first box on this page, you can set the harbour fees ship owners need to pay for sailing to this harbour. The second box is where you build the ships, just select a ship type, give it a nice name, put a price on the ship and click op produce. The third box shows what ships you currently have for sale in your wharf. The fourth box shows your current skills on the production of ships and here you can raise the skill points as well.