For the payment of the principal and interest of the bonds the Harbor Bond Sinking Fund shall consist of the following:
(a)
Payments from any available moneys in the San Francisco Harbor Improvement Fund, from time to time on order of the authority, of amounts equaling, in the aggregate:
(1)
That required under this part to be expended from the Harbor Bond Sinking Fund and the General Fund, to pay the principal and interest on all bonds issued at the instance of the authority;
(2)
Plus interest as required to be paid to the General Fund under Section 3910 on any amounts paid from the General Fund by reason of insufficient payments having been made from the San Francisco Harbor Improvement Fund to pay, when due, the principal and interest on any bonds issued at the instance of the authority;
(3)
Less the amount equal to any interest that accrues from the investment of money in the Harbor Bond Sinking Fund which has been paid into that fund from the San Francisco Harbor Improvement Fund.
(b)
Payments from any available moneys in the Small Craft Harbor Improvement Fund from time to time, on order of the commission, of amounts equaling, in the aggregate:
(1)
That required under this part to be expended from the Harbor Bond Sinking Fund and the General Fund, to pay the principal and interest on all bonds issued at the instance of the commission;
(2)
Plus interest required to be paid to the General Fund under Section 3910 on any amounts paid from the General Fund by reason of insufficient payments having been made from the Small Craft Harbor Improvement Fund to pay, when due, the principal and interest on any bonds issued at the instance of the commission.
(3)
Less the amount equal to any interest that accrues from the investment of money in the Harbor Bond Sinking Fund which has been paid into that fund from the Small Craft Harbor Improvement Fund.