Maragogi is a municipality of the Brazilian state of Alagoas in the 125 km north of Maceió capital city. Has 25,726 inhabitants, a city situated on the northern coast of Alagoas state, Brazil, being the easternmost city of that state.
As the main destination in the State of Alagoas after its capital city, Maragogi attracts visitors from Maceió. From Japaratinga beach, on the southern tip, a ferryboat crosses Manguaba River into Porto das Pedras, where visitors find virtually deserted beaches. Maragogi was initially a small village called Gamela. In 1887, it was granted the status of a Town and adopted the name of Isabel, to honor the Brazilian Princess who signed a law ending slavery in Brazil. Later on, in 1892, it was named as Maragogi after the river that baths the city. "Maragogi", according to some historians, comes from “Marahub-gy”, or river of the Marauba tribes.
A Jangada is a traditional fishing boat made of wood used in the northern region of Brazil. Some claim the historical legacy of the jangada dates back to the ancient Greeks and that it was Ulysses' vessel in The Odyssey.
The construction of the jangada incorporates some improvements in neolithic handcraft - better materials were found and the physics of sailing was better observed through experimentation. The details are closely guarded by artisans.
Its triangular sail makes use of some effects of fluid dynamics. Also known as a "latin" (lateen) sail, it allows one to sail against the wind, taking advantage of the pressure difference on the air that rises on its external face (the one that becomes convex for the internal wind pressure) and its internal face (the one that becomes concave, the side where the sailor goes). Some big watercraft also used the Latin sail, but in a limited manner, because its successful use was crucially dependent on the presence of the sailor, who must be aware of the wind movements: the pressure difference is manipulated constantly whilst sailing against the wind. The same principles are used to keep a plane in the air, thanks to its wing geometry.
In the jangada, there is a gracious curve almost parabolic on the upper part of the triangle, and another one more extended and short, below. This asymmetry is due to the manipulation high of the mast, that turns gently - this time using the lever mechanic principle - around its axis.