Section 5
SEC. 5. All such funds used for the construction of the vessels or watercrafts herein contemplated shall be self-liquidated within a period not to exceed twenty years and shall bear interest at the rate of not more than four and one-half per cent per annum: Provided, however, That a down payment from owner or operator of not less than twenty per cent of the price of the vessel shall be paid upon the execution of the contract for the construction of such vessels or watercrafts: Provided, further, That such vessels shall be fully insured by the owner or operator: And provided, finally, That no right secured under this Act by the owner of the vessel shall, during the existence of the contractual agreement, be transferred or encumbered to third parties without the consent of the National Shipyards and Steel Corporation.