Cal. Pub. Util. Code § 727

It is the policy of the state that the use of all waterways, ports, and harbors of this state shall be encouraged, and to that end the commission is directed in the establishment of rates for water carriers applying to business moving between points within this state to fix those rates at such a differential under the rates of competing land carriers that the water carriers shall be able fairly to compete for such business. In fixing the rates there shall be taken into consideration quality and regularity of service and class and speed of vessels.