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© McCord Museum
Dredge No. 1, Dept. of Marine, QC, about 1910
Anonyme - Anonymous
About 1910, 20th century
Silver salts on paper mounted on paper - Gelatin silver process
20 x 25 cm
Gift of Mr. John L. Russell
© McCord Museum

Keys to History:

River Dredges
The St. Lawrence River is known for its sandbars, its winding course and its strong currents. Sailors have to be very watchful when navigating it. The river even caught the skilled sailor Jacques Cartier; his ship went aground in low water in Lac St. Pierre in the 16th century. By the 19th century pressure on the government to ensure that ships could safely enter and leave harbours such as the one at Montreal had reached a pitch, and in 1844 it ordered the dredging of a channel in Lac St. Pierre. The resulting channel measured 3 metres at its deepest point, followed a gradual curve and was marked by several lighthouses.

Lack of funding slowed down dredging operations in the river until 1865 and the start of a major project. That project was financed by the government through borrowing and the levying of a ship tax (based on tonnage) A channel more than 90 metres wide and 6 metres deep was dug by an armada of dredges, built by a shipyard in Sorel, Quebec.


Dredges are ships designed to dig, or dredge out, navigation channels. They are equipped with underwater buckets that rake the bottom of a river or waterway to provide a certain depth of water for ships.


Dredge No. 1 worked in shallow waters. Here it is seen ready to dredge a shipping channel in the St. Lawrence River.


Only one channel was built using dredges in the 19th century in Canada, but they were very much in use later, especially after the opening of the St. Lawrence Seaway in 1959; its channels must be maintained at a minimum depth of 8.2 metres.


In Canada, dredges-like lighthouses, buoys and icebreakers-are the responsibility of the federal government. At the time this photograph was taken, they were operated by the Department of Marine and Fisheries.

© Musée McCord Museum