"Chattel paper" means a writing or writings which evidence both a monetary obligation and a security interest in or a lease of specific goods, but a charter or other contract involving the use or hire of a vessel is not chattel paper. When a transaction is evidenced both by a security agreement or a lease and by an instrument or a series of instruments, the group of writings taken together constitutes chattel paper. (CCP 481.040, 680.140;COMM 9102(a)(11))