Contact Public Affairs

U.S. Army Corps of Engineers
St. Paul District
Public Affairs Office
332 Minnesota St., Suite E1500
St. Paul, MN 55101

Phone: (651) 290-5807
Fax: (651) 290-5752 


Dredge Thompson patterns tell a story of the district’s history

Published Feb. 25, 2014
A district team visited the Lock and Dam 5A warehouse in Fountain City, Wis., Nov. 15, 2013, to inventory a large pile of wooden patterns used for the Dredge William A. Thompson, which served the district from 1937 to 2006.

The Dredge Thompson, eligible for listing on the National Register of Historic Places, was recently acquired by the Prairie du Chien Community Development Alternatives, Inc. This group plans to convert the vessel into a museum of river transportation highlighting the dredging machine itself, social aspects, the national impact and its role in transforming the nation’s transportation system and the river. A key part to this history is the patterns uniquely built for the dredge.

“The patterns are currently stored in wooden crates and stacked about two stories high in the warehouse. They were previously stored in the ‘pattern’ building in Fountain City until the building was demolished because of safety issues,” said Brad Perkl, planning.

The dredge patterns range in size from large to small. Some of them measure 12 feet in length or diameter, while others are the size of a shoe box.

Kenton Spading, engineering and construction, said the patterns were used to make replacement parts for the large machinery on the vessel. Inventory sheets showed that some patterns were frequently shipped off to be cast, while others were not used at all. “When a replacement part was needed for the Dredge Thompson, another vessel, or one of the lock and dams, the pattern was shipped to a foundry,” he said. “The foundry made a mold by placing the wooden pattern into a mixture of sand and clay for casting. The mold was then filled with molten metal, left to cool, and the metal part was extracted, finished and readied for return shipment.”

The team plans to finish cataloging all of the patterns before shipping to Prairie du Chien, Wis., to reunite with the vessel.