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"The dredges on this pattern, used in Britain for ten years after their first introduction, about the year 1838, were usually small and rather heavy, not more than 12 to 15 inches in length, by 4 or 4.5 inches in width at the mouth. Two scrapers, the length of the dredge-frame, and 1.5 to 2 inches wide, were set at an angle of about 110 degrees to the plane of the dredge's mouth, so that when the dredge was gently hauled along it took hold of the ground and secured anything loose on its surface." — Encyclopedia Britannica, 1893

Ball's Naturalists' Dredge

"The dredges on this pattern, used in Britain for ten years after their first introduction, about the…

Dredging, the excavating or scooping out of soil, mud, sand or rock under water by a machine called a dredge. Dredging is used in deepening and widening the beds of rivers, canals, harbors. The forms of modern dredges are very numerous, different conditions requiring different forms.

Dredge

Dredging, the excavating or scooping out of soil, mud, sand or rock under water by a machine called…

"A machine used for clearing out or deepening the channels of rivers or harbors. Dredging-machines are variously constructed, the simplest being like the oyster-dredge described above, only having a perforated cowhide bag instead of the chain-net, and a stronger 'spoon' or iron mouth to the bag." — Chambers' Encyclopedia, 1875

Dredge Machine

"A machine used for clearing out or deepening the channels of rivers or harbors. Dredging-machines are…

An illustration of a conical dredge being hoisted in.

Conical Dredge

An illustration of a conical dredge being hoisted in.

Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow seas or fresh water areas with the purpose of gathering up bottom sediments and disposing of them at a different location.

Excavating Purpose Dredger

Dredging is an excavation activity or operation usually carried out at least partly underwater, in shallow…

"Longitudinal section of hopper dredger, employed on the River Clyde. The vessel steams to place of working and is moored by the Steam Winches A A at bow and stern to buoys, the Bucket Ladder B is then lowered by steam power, and thereafter Buckets set in motion by gearing C C. The depth of water at which the Bucket Ladder dredges is regulated by the Hoisting Shears and Chain Barrel D D, driven by shafting E E from the Engines. The Buckets discharge the material by the shoot F into the Hopper G. The dredged material is discharged by the doors of the Hopper being opened by the Lifting Chains H H. These doors are hinged on to the side of Vessel, and suspended at centre by the Lifting Chains, which are connected to geared Crab Winches I I." -Hill, 1921

Hopper Dredger

"Longitudinal section of hopper dredger, employed on the River Clyde. The vessel steams to place of…

"Muller gives a quaint description not very unlike that used by Hall and Forbes, only the mouth of the dredge was square, a form which, unless used with great caution, gives fatal facilities for "washing out" in the process of hauling in." — Encyclopedia Britannica, 1893

Fredrick Muller's Dredge

"Muller gives a quaint description not very unlike that used by Hall and Forbes, only the mouth of the…

"Close to the place where the dredge is emptied there ought to be a tub about 2 feet in diameter and 20 inches deep, provided with a set of sieves so arranged that the lowest sieve fits freel within the bottom of the tub, and the three remaining sieves fit freely within one another. Each sieve has a pair of iron handles through which the hand can pass easily, and the handles of the largest sieve are made long, so that the whole nest can be lifted without stooping or putting the arms into the water." — Encyclopedia Britannica, 1893

Set of Sieves

"Close to the place where the dredge is emptied there ought to be a tub about 2 feet in diameter and…

A ship used for lifting mud and silt from the bottom of rivers, harbors, and canals.

Dredging Ship

A ship used for lifting mud and silt from the bottom of rivers, harbors, and canals.