On the Water

Ship Model, Hopper Dredge Willets Point

Hopper dredges are used to clear channels and offshore sandbars as well as sediment deposits that restrict navigation into rivers and harbors. They work like underwater vacuum cleaners: each dredge is equipped with a suction pipe, or drag arm, that gathers up sediment from the bottom. The dredged sediment is then stored in the ship’s interior containers, or hoppers. When the hoppers are full, the dredge uses a series of pumps and pipelines to transport the sediment to a secondary location for disposal.

Built in 1926 by the Federal Shipping Company, a subsidiary of U.S. Steel, in Kearny, New Jersey, the hopper dredge Willets Point could raise sediment from depths of 12 to 35 feet. This 200-foot vessel was designed for the U.S. Army Corps of Engineers and represents the type of equipment used in early 20th-century harbor improvement work. In 1927 the Willets Point was commissioned to dredge sections of the Potomac River. At the time, large vessels could not reach Alexandria, Virginia, and Washington, D. C., because of sedimentation in the channels and harbors. Between January and April 1927, the Willets Point moved 581,507 cubic yards of sediment from the bottom of the Potomac.

Hopper dredges cannot move quickly while working. As a result, dredges use a series of signal patterns to let nearby ships know when they are actively working. During the day an arrangement of black circles and diamonds is raised up on the mast, while at night the dredges use an alternating pattern of red and white lights.

This cutaway model was built by Severn-Lamb Ltd., in Stratford-on-Avon, England.

ID Number:
TR*330083
Date:
1970
Dimensions:
8 3/4 in x 25 in x 7 in; 22.225 cm x 63.5 cm x 17.78 cm

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