The Postal Service may require that mail be transported by freight or express when— (1) there is no competition on a water route and the rate or compensation asked is excessive; or (2) no proposal is received. A common carrier by water that fails or refuses to transport the mail when required to do so under this section shall be fined not more than $500 for each day of refusal. ( Pub. L. 91–375 , Aug. 12, 1970 , 84 Stat. 773 .) Statutory Notes and Related Subsidiaries Effective Date Section effective July 1, 1971 , pursuant to Resolution No. 71–9 of the Board of Governors. See section 15(a) of Pub. L. 91–375 , set out as a note preceding section 101 of this title . CFR Title Parts 39 601