SUBMERSIBLE STOOL:

Used primarily on women accused of witchcraft. The chair was submerged under water leaving the tortured person pinned under the water unable to breathe, the inquisitor had decided how long the torture or torture remain submerged, the process usually repeated until the dying drowned or tortured confession, in which case the defendant ran choking, or burning later.

How long endure under water plant in this chair designed to make witches confess?