... made of small pieces of wood spliced two or three times. To the apex of the "A" is attached a forked stick, over which run the halyards. The rectangular "sail" is nothing more nor less than a large mat made of rushes. A short forestay fastened to the sides of the "A" about four feet above the hull prevents the mast from falling when the sail is hoisted. The main halyards take the place of a backstay. The balsas cannot beat to windward, but behave very well in shallow water ... — Inca Land - Explorations in the Highlands of Peru • Hiram Bingham
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