Any municipal corporation or port district operating or maintaining a port may apply to the commission for the issuance of a certificate of convenience and necessity to require any person or corporation operating vessels between points in this State, to serve that port. The commission may, after hearing, issue the certificate as prayed for, or refuse to issue it, or issue it for the partial exercise of the rights granted by any such certificate, upon such terms and conditions as in its judgment the public convenience and necessity require, and upon making the order the person or corporation to which the certificate is issued, shall be compelled to perform the

service.