If a port fails or refuses to levy the special tax provided by ORS § 777.430 (2), within the time provided, in an amount sufficient to pay the interest accruing during the 12 months following October 1 next ensuing on bonds theretofore issued by the port and then outstanding, together with any portion of the principal of such bonds maturing within the 12 months, the county board of the county in which the port is located, shall levy at its July term immediately following such failure or refusal by the port, a tax on all the taxable real and personal property situated within the port, at a rate sufficient to pay such interest and principal. [Amended by 1971 c.728 § 75]