Cal. RTC § 130

(a) “Vessel” includes every description of watercraft used or capable of being used as a means of transportation on water, but does not include aircraft.

(b) “Documented vessel” means any vessel which is required to have and does have a valid marine document issued by the Bureau of Customs of the United States or any federal agency successor thereto, except documented yachts of the United States, or is registered with, or licensed by, the Department of Motor Vehicles. “Documented vessel” does not include any vessel exempt from taxation under subdivision (l) of Section 3 of Article XIII of the Constitution of the State of California.

(c) “Vessel of the United States” means a documented vessel, that is, a vessel registered, enrolled and licensed, or licensed under the laws of the United States, except documented yachts of the United States.

(d) “Port of documentation” means the home port of a vessel as shown in the marine document in force and issued to the owner of such vessel by the Bureau of Customs of the United States or any federal agency successor thereto.

(e) “Marine document” includes registry, enrollment and license, and license.

(f) “In this state” means within the exterior limits of the State of California, and includes all territory within these limits owned by, or ceded to, the United States of America.

(g) “Natural resources” consist of both the living resources of the sea and the mineral and other nonliving resources of the seabed and subsoil together with living organisms belonging to sedentary species, which are organisms which, at the harvestable stage, either are immobile on or under the seabed or are unable to move except in constant physical contact with the seabed or the subsoil.

(h) “Oceanographic research vessel” means a vessel which the secretary of the department in which the United States Coast Guard is operating, or his successor, finds is an oceanographic research vessel under the laws of the United States.