A fore-and-aft rig is a sailing ship rig with sails set mainly in the median plane of the keel, rather than perpendicular to it, as on a square-rigged vessel.
The gaff-rigged schooner Effie M. Morrissey
Micronesian wa with crab claw sail
The earliest European fore-and-aft rigs appeared in the form of spritsails in Greco-Roman navigation, as this carving of a 3rd century AD Roman merchant ship
One of the ships in Borobudur depicting a double-outrigger vessel with fore-and-aft tanja sails on tripod masts (c. 8th century AD)
Austronesian sail types are typically fore-and-aft with spars along one or more edges and include a triangular variant with spars on the upper and lower edges, informally called a crab claw sail. They
Fore-and-aft rig
…include staysails, Bermuda rigged sails, gaff rigged sails, gunter rig, lateen sails, lug sails, tanja sails, the spanker sail on a square rig, and crab claw sails. Fore-and-aft rigs include…
1846 illustration of a Fijian camakau, a single-outrigger canoe with a canted mast "crane sprit"-type crab claw sail
Hokule'a in 2009, with crab claw sails where the upper spars also function as fixed masts
Crab claw sail being constructed for Hot Buoys trimaran. Notice pocket in right hand edge of sail to hold spar. Second spar in this particular configuration is not required since a bolt-rope holds the sail's upper edge and the mast is located in the back of the sailboat. Note lack of shaping.
"Crane sprit" type crab claw rig of the Philippines with a fixed mast