A water blast gun support apparatus and methods for enabling the operator to direct the gun by a joystick attached to a pneumatic sinusoidal biasing control unit. Depending upon the direction the joystick is pointed by the operator, a controlled flow of air is delivered to pneumatic motion producing actuators which move the water blast gun to the desired position and maintain this position when the operator moves the joystick to its neutral position. The support apparatus absorbs the thrust of the water so that the operator is relieved from having to physically counter the force of the water.