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Soo Locks - ever dependable through the ups and downs of Great Lakes shipping

Date Posted: April 2 2004

SAULT STE. MARIE – The 21-foot drop in water levels from Lake Superior down to the lower Great Lakes vexed British, French and native fur traders in the 1600s and 1700s, who were forced to portage their canoes and animal hides around the St. Mary’s River rapids.

Eventually, the ingenuity of man found a way to navigate around those rapids through a system of canals or wooden locks that mechanically raised and lowered vessels. The British first constructed a 38-foot-long wooden lock in 1797 as a passage around the rapids – but it was destroyed during the War of 1812. Other locks and canals followed, beginning in 1855.

The lay of the land hasn’t changed much at the Soo over the past 300 years, and the need for locks to make the waterways navigable hasn’t changed, either. Long-gone are the wooden locks, and the “modern” locks that are in place today have provided tremendous service over the years, even though the oldest is 90 years old.

The current system of locks is No. 2 on the list of the state’s top 10 civil engineering projects of the 20th Century as designated by the Associated Underground Contractors, with the Mackinac Bridge at No. 1. The locks were also added to the roster of National Historic Places in 1966.

The locks that are at the Soo include the Davis (built in 1914, 1,350-feet long by 80 feet wide), the Sabin, (1919); the MacArthur (1943) and the largest, the Poe (1968, 1,200-feet long by 110-feet wide). Only the Sabin is no longer in use.

“Given the conditions they work in and the amount of their use, the locks are in very good condition, and they’re very reliable,” said Stan Jacek, Soo-area engineer for the Army Corps of Engineers, which has jurisdiction over the locks.

The Poe Lock took six years to build, and is the only lock ever constructed between two operating locks. The Poe Lock is also the only indispensable lock – it handles the largest freighters and about 70 percent of shipping traffic through the Soo. A mechanical breakdown for any length of time would be disastrous for Great Lakes shipping industry

Michigan congressional representatives have been lobbying for years, unsuccessfully, for the estimated $225 million to pay for construction of another lock the same size as the Poe, which would replace the Davis and Sabin Locks. Jacek said the new lock won’t be constructed any larger than the Poe Lock, because that would lead to the construction of bigger freighters, which would negate the use of the Poe as a backup lock.

Repairs and maintenance to the Poe Lock must be done during the winter months, when there is no shipping. In the past five years, building trades workers have performed more than $5 million in renovations on that lock. This winter, aside from small Homeland Security projects such as the installation of better lighting, maintenance activity for the building trades has been minimal.

Ships transport an average of 83 million tons of cargo a year through the locks. The most common ship-borne product to move through is iron ore, at an average of almost 50 million tons per year.

“Certainly there is no other lock complex like this in the world, with four locks set up side by side,” Jacek said. “We’ve been very fortunate not to have any major shutdowns over the years, but a lot of that is because of good maintenance.”


THE SECOND-LARGEST lock at the Soo, the MacArthur, is constructed in May 1943. (Photo courtesy Army Corps of Engineers)