From the Model in the Victoria and Albert Museum.
THE BUCKET-DREDGER “PELUSE.”
From a Photograph. By permission of Messrs. Lobnitz & Co., Ltd.
The suction-dredger, on the other hand, as its name signifies, does not scoop up the sand, but sucks it up into her holds through pipes which reach down to the bed of the river or estuary. The largest of these is well-named, and is illustrated [opposite page 242]. This represents the Leviathan, which is owned by the Mersey Docks and Harbour Board, Liverpool, and it is through her work that the river is able to be maintained in a navigable condition. This voracious animal sucks up sand at the rate of 10,000 tons in less than an hour, by means of centrifugal pumps, and when loaded with this heavy cargo steams out to sea at a speed of ten knots, and then by means of doors discharges the sand through her bottom. The doors are worked by means of hydraulic machinery. She herself is propelled by four sets of triple-expansion engines, which also work the centrifugal pumps. We can get some idea of the size of this dredger when we remark that her enormous length of 500 feet makes her as long as the Etruria.
The owners of the Leviathan are also the proprietors of the ship shown in [our next illustration]. This, the Vigilant, is seen alongside the crane in the Herculaneum Dock, Liverpool. The Dock and Harbour Boards are practically local Trinity House brethren, though totally independent bodies. Just as the Trinity House authorities have the upkeep of the light-houses and lightships round the English coast, so the Dock and Harbour Boards are charged with the duties of keeping the local buoyage in efficient order for ensuring safe navigation into and out of their ports and estuaries. Gas buoys have to be refilled periodically, moorings have to be laid down afresh, and, in the case of damage, replaced. Periodically these have, in any case, to be brought ashore to be overhauled, repainted and then returned to their duties, bobbing about to the ceaseless heave of the waves. For such work as this the Vigilant is employed. The illustration shows a gas buoy being lowered on to her deck from the quay. Not very long ago an out-going steamship from Liverpool fouled one of the Mersey buoys in a curious manner. She was proceeding in such close proximity to the latter that she actually caught her propeller in one of the mooring chains, with, as may be expected, consequent damage.
THE SUCTION DREDGER “LEVIATHAN.”
From a Photograph. By permission of the Mersey Docks and Harbour Board.
