Sung mainly when heaving up anchor, outward bound, was one of the most bracing of all shanties - "Rio Grande." It has been suggested that it refers to the famous river on the Mexican border. It seems clear, however, that it was first sung in the Brazil trade and was inspired by the port and province of Rio Grande do Sul. Most version show plainly that the Rio Grande of the shanty was not simply a river, but a port or region; one version, for example, runs, "There the Portugee girls may be found." Usually known succinctly as "Rio Grande," the southern Brazilian province and its chief port, of the same name, carried on a busy trade with the United States and Britain, outdoing in this respect all of the many other Rio Grandes on the map. A line traditional in the shanty says the river "brings down golden sand." This refers not to the gold of southern Brazil but to the shifting sand shoals in the Rio Grande estuary, which rendered access to the port so difficult that vessels of more than limited draft could enter only when the tide was favorable. (Much of the "golden sand" has been eliminated by dredging operations carried on since the eighties.) Thus the shanty really doesn't concern a river at all - the estuary, though called a "river," is the mouth of the passage connecting the Lagoa dos Patos with the open sea.
"This shanty," said Captain Patrick Tayluer, "was generally sung aboard of those little Baltimore vessels that used to run down to São Paulo and back to the United States with coffee - to São Paulo and the Rio Grande and Brazils. It was a beautiful place, and the sailors used to love it - and the song was sung by seamen all over the world."
-William Doerflinger, Songs of the Sailor and Lumberman