Only Brazilian-flagged vessels may engage in the transport of goods in cabotage navigation and inland navigation along the national route, as well as in port support navigation and maritime support navigation. Brazilian-flagged vessels must have a Brazilian captain.
"Art. 4. In Brazilian-flagged vessels, the captain, the chief engineer and two-thirds of the crew will necessarily be Brazilian.[…]" (Law No. 9,432 reordering the maritime transport (8 January 1997), Article 4 [google translation])
Law No. 9,432 reordering the maritime transport (8 January 1997), last amended by Law No. 12,599 of 2012, Article 4
[<a href="http://www.planalto.gov.br/ccivil_03/leis/L9432.htm">Law</a>]