Revenue bonds.

(1) The governing body of any unit shall have the power and it is hereby authorized to provide by ordinance or resolution, at one time or from time to time, for the issuance of revenue bonds of the unit for the purpose of paying all or a part of the cost as hereinabove defined of any one or more self-liquidating projects of the same class, or any combination thereof as a single project, or of any improvements thereof. The principal and interest of such bonds shall be payable solely from the special funds herein provided for such payment. The bonds of each issue shall be dated, shall bear interest at such rate or rates not exceeding 7.5 percent per annum, shall mature at such time or times not exceeding 40 years from their date or dates, as may be determined by the governing body, and may be made redeemable before maturity, at the option of the unit, at such price or prices and under such terms and conditions as may be fixed by the governing body prior to the issuance of the bonds. The governing body shall determine the form of the bonds and the interest coupons to be attached thereto, the manner of executing the bonds and coupons, and shall fix the denomination or denominations of the bonds and the place or places of payment of the principal and interest, which may be at any bank or trust company within or without the state. In case any officer whose signature or a facsimile of whose signature shall appear on any bonds or coupons shall cease to be such officer before the delivery of such bonds, such signature or such facsimile shall nevertheless be valid and sufficient for all purposes the same as if he or she had remained in office until such delivery. All revenue bonds issued under the provisions of this part shall have and are hereby declared to be and to have all the qualities and incidents of negotiable instruments under the negotiable instruments law of the state. Provision may be made for the registration of any of the bonds in the name of the owner as to principal alone and also as to both principal and interest, and for the reconversion of any of the bonds registered as to both principal and interest into coupon bonds. Such bonds may be issued without regard to any limitation on indebtedness prescribed by any other law and shall not be included in the amount of bonds which any unit may be authorized to issue under any statute or charter. The governing body may sell such bonds in such manner and for such price as it may determine to be for the best interests of the unit, but no such sale shall be made at a price so low as to require the payment of interest on the money received therefor at more than 7.5 percent per annum, computed with relation to the absolute maturity of the bonds in accordance with standard tables of bond values, excluding, however, from such computation the amount of any premium to be paid on the redemption of any bonds prior to maturity. Prior to the preparation of definitive bonds, the governing body may, under like restrictions, issue interim receipts, interim certificates, or temporary bonds, with or without coupons, exchangeable for definitive bonds when such bonds have been executed and are available for delivery. The governing body may also provide for the replacement of any bonds which shall become mutilated, or be destroyed or lost. Such revenue bonds may be issued without any other proceedings or the happening of any other conditions or things than those proceedings, conditions or things which are specifically required by this part.

(2) The proceeds of such bonds shall be used solely for the payment of the cost of the project, and shall be disbursed in such manner and under such restrictions, if any, as the governing body may provide. If the proceeds of such bonds, by error of estimates or otherwise, shall be less than the cost of the project, additional bonds may in like manner be issued to provide the amount of such deficit, and, unless otherwise provided in the ordinance or resolution or in the trust agreement hereinafter mentioned, shall be deemed to be of the same issue and shall be entitled to payment from the same fund without preference or priority of the bonds first issued for the same project. If the proceeds of bonds issued for any project shall exceed the cost thereof, the surplus shall be paid into the fund hereinafter provided for the payment of the principal of and the interest on such bonds.

(3) In the event that a unit has heretofore acquired or constructed a project as hereinabove defined, and, to pay the cost of such acquisition or construction or of improvements thereof, shall have issued revenue bonds or certificates of the unit payable from the revenues of such project or any other special funds provided for herein, and in the further event that such unit shall desire to construct additions, extensions, improvements or betterments to such project or to acquire by purchase or to construct an additional project and to combine such additional project with the project theretofore purchased or constructed, and to refund such outstanding revenue bonds or certificates, such unit may provide for the issuance of a single issue of revenue bonds under the provisions of this part for the combined purposes:

(a) Of refunding such revenue bonds or certificates then outstanding if they have matured or shall then be subject to redemption or will be subject to redemption within 10 years thereafter, or can be acquired for retirement, and

(b) Of constructing such additions, extensions, improvements or betterments or of acquiring by purchase or of constructing such additional project, and the principal of and interest on such revenue bonds shall be payable from the revenues derived from the operation of the combined projects as a single project, and any other special funds pledged therefor as provided herein.

(4) The ordinance or resolution providing for the issuance of the revenue bonds and the trust agreement hereinafter mentioned, may also contain such limitations upon the issuance of additional revenue bonds as the governing body may deem proper, and such additional bonds shall be issued under such restrictions and limitations as may be prescribed by such ordinance or resolution or by the trust agreement hereinafter mentioned. All moneys received from any bonds issued and sold under the provisions of this part shall be applied solely for the purposes for which the bonds shall be authorized or to the sinking fund created for the payment of such bonds.

(5) No revenue bonds shall be issued by a unit under the authority of this part unless the governing body of such unit shall have theretofore found and determined:

(a) The estimated cost of the project on account of which such bonds are to be issued,

(b) The estimated annual revenues of such project, and of any other special funds provided for in this part which are to be pledged as additional security for said bonds, and

(c) The estimated annual cost of maintaining, repairing and operating the project and the interest on such bonds and the principal thereof as such interest and principal shall become due.