On asquare riggedship, thespankeris agaff-riggedfore-and-aftsail set from and aft of the aftmostmast. Almost all square rigs with more than one mast have one or two spankers, which evolved from thedriver sail. Some also carry a triangulartopsailabove the uppermost or only spanker, between the gaff and the mast, called thegaff sail. A spanker in this situation is often ‘soft footed’ in that it has no boom to which it is attached at its foot.
The term was also briefly used commercially for a branded type ofspinnaker.