 The trough was supported by 5 cylindrical floats each immersed in 40 metre deep water-filled wells.The lift from the floats was the same as the load of the water filled trough therefore, only a small electric motor sufficient to overcome friction and viscous resistance was needed to set the trough in motion in either direction.Four steel worm gears, 20 metres long and 280 mm in diameter were used to direct the trough in the appropriate course.