describes two different styles of sail that help maintain a boat’s direction into or nearly into the wind during heavy weather or while at anchor. One style is a flat-cut sail with no belly; this is rigged from the backstay and tacked off to one rail at the shrouds. The other style is shaped like a wedge; this is rigged from a boom’s aft end and tacked to each quarter. Also called an anchor sail, backing sail, or stability sail. A riding sail is often used in combination with a sea anchor while at sea in storm conditions.