WORLD’S BIGGEST DREDGER

Evening Star, Issue 22573, 15 February 1937, Page 6

WORLD’S BIGGEST DREDGER

SCOOPS OUT YANGTSE RIVER One year’s operation of the largest and most powerful dredger of its type in the world has achieved marked results in dealing with the problem of the Yangtse Bar, and probably will result in the purchase of a second dredger of the same sort. A bulletin issued on the record _of the £151,800 dredger Chien Shein improving the condition of the “Fairy Flats ” for passage of ocean liners on their way up the Yangtse shows great progress in dealing with the problem of a bar which, resulting from the sweeping down of silt from tens of thousands of square miles of interior China, stretches two miles wide out into the sea to a distance' affecting deep draft ships about 20 miles from shore, To make a suitable navigable trench in the bar, it is regarded as the ideal to scoop out a passage 100 ft wide and with a botten level nine feet below the crest of the bar. This enormous task would involve the removal of more than 20,000,000 cubic yards of mud and sand, with a simultaneous battle to keep ahead of the resilting which constantly occurs. Ever since the “ de Bijke Report ” of •1876 this problem has been realised and as ships have increased in size, it has been growing. Dr Herbert Chatley, British engineer-in-chief of the Whangpoo Conservancy Board, recommended a project for dredging by the drag suction method and eventually the Chien was built in Germany at Elbing. It was put to work on a revised project for dredging a channel at least 600 ft wide, nine feet below the crest, and up to about 25 miles in length; in its third year it cut a channel 600 ft wide, about three feet deep and three miles long—which is regarded as a promising beginning fully warranting the continuation of the scheme. GOOD AVERAGE SPEED. Dredged material has been transferred to a dumping ground two miles from the Scene of operations. It is pointed out that over 60 per cent, of the output consisted of hard sand, not only difficult to dredge but tending to settle quickly into the mixture, resulting in a low average hopper density. The dredger moves at an average speed of three knots, and has proved satisfactory in dealing with prevailing cross currents. In the year passed, 2,271 “dredging hours” were logged. A new revised edition of ‘The Port of Shanghai ’ —the booklet issued by the Whangpoo Conservancy Board, which deals with the welfare of Shanghai’s river—makes three suggestions for improving the port: To lower freight rates by providing accommodations for ships of most economic size, diminution of handling charges by provision of better facilities, and the influencing of routes on land and sea so that concentration and efficiency may favour direct routes.