<P> Argentina effectively recognized Chilean sovereignty over the Strait of Magellan in the Boundary treaty of 1881 between Chile and Argentina . Argentina had previously claimed all of the strait, or at least the eastern third of it . </P> <P> In 1840 the Pacific Steam Navigation Company was the first to use steamships for commercial traffic in the strait . </P> <P> Until the Panama Canal opened in 1914, the Strait of Magellan was the main route for steamships traveling from the Atlantic Ocean to the Pacific . It was often considered the only safe way to move between the Atlantic and Pacific Oceans, as the Drake Passage separating Cape Horn (the southern tip of South America) from Antarctica is notorious for turbulent and unpredictable weather, and is frequented by icebergs and sea ice . Ships in the strait, protected by Tierra del Fuego to the south and the coast of continental South America to the north crossed with relative ease, and Punta Arenas became a primary refueling port providing coal for steam ships in transit . Sailing ships, however, partly because of variable winds and currents in the strait, generally preferred the Drake Passage, as they had more room to maneuver there . </P> <P> The strait is approximately 570 kilometres (310 nmi; 350 mi) long and about 2 kilometres (1.1 nmi; 1.2 mi) wide at its narrowest point (Carlos III Island, west of Cape Froward). The northwestern portion of the strait is connected with other sheltered waterways via the Smyth Channel . This area is similar to the Inside Passage of Alaska . South of Cape Froward, the principal shipping route follows the Magdalena Channel . </P>

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