The Board of Supervisors of the Association shall maintain a Maintenance and Replacement Fund for the replacement and repair of the major equipment of the Association. The State Board of Pilots shall determine a percentage of the pilotage fees collected by the Association to be set aside in the Fund. The Board of Supervisors of the Association shall obtain written approval from the State Board of Pilots for any expenditures from the Fund. Except as provided in paragraph (2) of this subsection, the balance in the Fund shall remain at or above $500,000. The balance of the Fund may fall below $500,000 for expenditures authorized by the Board. The balance of the Fund may not remain below $500,000 for more than 10 consecutive years. At no time shall the balance of the Fund fall below $100,000. The Board of Supervisors of the Association shall deposit the money authorized under subsection (b) of this section into the Maintenance and Replacement Fund. The Board of Supervisors of the Association shall hold the Maintenance and Replacement Fund in trust. The Association: may invest or hold the Fund in any manner that the Association finds desirable, in light of the nature and purpose of the Fund; may place control and management of the Fund, or a part of the Fund, with a bank or trust company that is subject to State or federal regulation; and is not limited to investments in property that has been designated, under any law of the State, as strictly suitable for investment of a trust fund. Assets held in trust under this section are not subject to attachment or execution.