Cutting of underwater trenches for cable laying - with oscillating high pressure water nozzles moved by double acting fluid cylinders

摘要

A plough shaped frame is equipped with a vertical and a horizontal nozzle tube. The upper end of the vertical and the trailing end of the horizontal tube are fixed to double acting cylinders which impart axial and rotational oscillation. The frame is towed along the sea or river bed by a ship in such a way that the water jets from the nozzles wash away the sea bed so that a trench is formed. The function of the horizontal nozzle tube at the bottom end of the frame is to undercut the trench walls so that they collapse and cover the cables after they have been placed in the trench. The nozzle tube oscillation increases the speed at which a trench can be cut.