A hand drill that can be used in a river on a barge or on a platform built on two large canoes. Basically, it consists of four straight poles, 5 to 7 in (12.7 to 17.8 cm) in diameter at the large end, which are set into notches in planks to prevent their sinking into the ground. The poles are joined at the top by a shaft that holds the pulley for the drill wire or rope. The walking beam is activated by 8 to 10 persons lining up on the crossarm. They pull down to raise the tools and vary their manner of movement, depending on whether they are driving casing, drilling, or pulling casing. The Ward drill is most efficient in shallow ground, but can be used in depths up to 90 ft (27.4 m).