A city council may by a two-thirds vote of all its members acquire lands or lands covered with water or buildings, for sites for public passenger docks. The lands must be acquired by purchase or by condemnation under chapter 117. A site for a public dock must not be acquired unless the council decides by two-thirds vote of all its members that the dock site is needed. The council may improve sites acquired for public docks by building and maintaining suitable buildings and suitable piers on the land. The city may by ordinance provide for the regulation, control, and operation of the docks, buildings and piers, and fix fees for their use.