In its natural state the River Clyde was a shallow water course as far downstream as West Ferry / Dumbarton. The 'Clyde Navigation' is a man-made seaway that was created over many years by a continuous programme of deepening, dredging, rock-blasting and diversion of the natural course of the river. At the begining of the 19th Century it was difficult to take vessels drawing more than 4 or 5 feet above Port Glasgow. By the fourth decade of the 20th Century it was possible to build, launch and navigate the two largest ocean liners in the world, drawing well over 30 feet, down the river from Clydebank to the Tail of the Bank (RMS Queen Mary and RMS Queen Elizabeth). During the peak years of the port of Glasgow, the Clyde Navigation Trust maintained a large fleet of dredgers and hopper barges to service the Navigation. Thus was derived the once well known phrase 'Glasgow made the Clyde and the Clyde made Glasgow'. With the significant dimunition of traffic to the port and the closure of a large proportion of the Clydeside shipbuilding and engineering industries, Clydeport, the private enterprise successors of the Clyde Navigation Trust, banished the native dredging fleet, sometimes known as the 'Skye Navy' (due to the propensity of Hebridean men in the crews), to history. Dredging of the Navigation was 'out-sourced'. Due to the reduced dredging requirements combined with the vast increases in the capability of modern dredging plant, the job is no longer continuous. This is a view of the Westminster Dredging Company's large (compared to the the Clyde's traditional machines) suction dredger W D Medway II making her way upriver off Dalmuir. This vessel visits the Clyde intermittently to maintain the modern river depth requirements.