The vessel known as the "proa" (or more accurately the "Pacific proa") in western terminology is more accurately a single-outrigger Austronesian boat with one sail (typified by vessels like the Chamorro "sakman"). Both ends are alike, and the boat is sailed in either direction, but it has a fixed leeward side and a windward side. The boat is shunted from beam reach to beam reach to change direction, with the wind over the side, a low-force procedure. The bottom corner of the crabclaw sail is moved to the other end, which becomes the bow as the boat sets off back the way it came. The mast usually hinges, adjusting its rake (mast). The proa is a low-stress rig, which can be built with simple tools and low-tech materials, but it is extremely fast. On a beam reach, it may be the fastest simple rig.