The state may at any time and from time to time issue refunding bonds for the purpose of refunding the principal of and the interest on any matured or unmatured bonds of the state then outstanding which were theretofore issued under any one or more of this article, or the 1957 Docks Act, or the 1959 Docks Act. The proceeds derived from the sale of such refunding bonds shall be paid to the State Treasurer and disbursed on order or resolution of the department solely to refund and retire those bonds for the refunding of which such refunding bonds are authorized to be issued, and to pay the expenses incurred in such refunding; provided, that pending the time such refunding can be consummated such proceeds may be invested as herein authorized. All provisions of this article pertaining to bonds issued under this article that are not inconsistent with the provisions of this section shall, to the extent applicable, also apply to the refunding bonds issued hereunder. The principal proceeds from the sale of any bonds issued hereunder, when not needed for the purposes for which such bonds were issued, and any other moneys received hereunder, when not needed for the purposes for which such moneys may be used, may at the discretion of the director, with the approval of the Governor, be invested in direct general obligations of the United States of America and the earnings on any investment so made shall be used in the same manner that the moneys so invested are herein provided to be used.