Cal. Rev. & Tax. Code § 230

(a) With regard to taxes that attach as a lien on or after January 1, 2001, wooden vessels of historical significance, and all personal property thereon used in their operation, are exempt from taxation. This exemption applies if all of the following conditions are satisfied:
1. (1) The owner and operator is a nonprofit organization that has qualified for exemption under either Section 23701d of this code or under Section 501(c)(3) of the Internal Revenue Code.
2. (2) No part of the net earnings of the owner inures to the benefit of any private shareholder or individual.
3. (3) The vessel is used primarily as, or as a part of, a maritime museum that is regularly open to the public.
4. (4) Income from fundraising use and use for charter activities does not exceed 40 percent of operating revenues of the vessel, and all net earnings are used to further the exempt activity of the museum.
(b) When claiming an exemption pursuant to this section, a claiming organization shall give all information required and answer all questions in an affidavit, to be furnished by the assessor, that is signed by the claimant under penalty of perjury. The assessor may require other proof of the facts stated in the affidavit before allowing the exemption. A claimant for an exemption pursuant to this section is subject to Sections 255 and 260.
(c) For purposes of this section, the following definitions apply:
1. (1) “Wooden vessel of historical significance” means any wooden vessel that is a refurbished original, wooden inland waters vessel of 47 feet or larger, built in California during or prior to 1910, that continuously thereafter has remained in California waters, and that has been designated a California State Historical Landmark.
2. (2) “Regularly open to the public” means that the museum was open to the public not less than 20 hours per week for not less than 35 weeks of the 12-month period immediately preceding the lien date for the year for which the exemption is claimed.