California Code, Harbors and Navigation Code - HNC § 656.1

(a) Locate and notify the owner or person in charge of the damaged property of the name and address of the operator and owner of the vessel involved, and upon locating the owner or operator of any other vessel involved, or the owner or person in charge of any other property damaged, upon being requested, exhibit the vessel registration and furnish the current residence address of the vessel's owner and operator to the other person.

(b) If the owner or person in charge of the damaged property or the owner or operator of any other vessel involved cannot be located, leave, in a conspicuous place on the property damaged or other vessel involved, a written notice giving the name and address of the operator and of the owner of the vessel involved and a statement of the circumstances of the accident, and, without unnecessary delay, notify the law enforcement agency having jurisdiction over the waterway or, if unknown, the sheriff of the county in which the accident occurred.