Vehicle Code § 9920
CHAPTER 3. Transfer of Title or Interest in Undocumented Vessel
When the secured party, his successor or assignee, has deposited with the department a properly endorsed certificate of ownership showing the secured party as legal owner, or if the vessel is not numbered when the owner shall file an initial application for number as provided for in this code, and the certificate of ownership issued under said application shows said secured party as the legal owner, and said certificate of ownership is deposited with the department, the deposit constitutes perfection of the security interest.