ducking stool

Historical a chair at the end of a plank, in which a culprit was tied and then ducked into water as a punishment

Origin: altered (infl. by duck) < cucking stool

See ducking stool in American Heritage Dictionary 4

noun
A device formerly used in Europe and New England for punishment, consisting of a chair in which an offender was tied and ducked into water.
link/cite print suggestion box