Traditional fishing boat were used for war and trade. Some ancient vessels were propelled by either oars or sail, depending on the speed and direction of the wind (see trireme and bireme). The Chinese were using sails around 3000 BC, of a type that can still be seen on traditional fishing boats sailing off the coast of Vietnam in Ha Long Bay. A jangada is an elegant planked fishing boat used in northern Brazil. It has been claimed the jangada dates back to ancient Greek time. It uses a triangular (lateen) sail, which allows it to sail against the wind. A felucca is
Transport in Sudan Khartoum. This dam has locks, but they have not always operated well, and the river has been little used from Khartoum to the port of Kusti, a railroad crossing 319 kilometers upstream. The Sennar and Roseires dams on the Blue Nile are without locks and restrict traffic on that river. In 1983 only two sections of the Nile had regular commercial transport services. The more important was the 1,436-kilometer stretch of the White Nile from Kusti to Juba (known as the Southern Reach), which provided the only generally usable transport connection between the central and southern parts of the country.