Proa

A proa, also seen as prau, perahu, and prahu, is a type of multihull sailboat. It is a vessel consisting of two (usually) unequal length parallel hulls. It is sailed so that one hull is kept to windward, and the other to leeward, so that it needs to "shunt" to reverse direction when tacking. The English term proa usually refers specifically to the South Pacific proa as described in the journals of the British ship HMS Centurion.