Soo Locks Empties its Largest Lock, See Inside

SAULT STE. MARIE, MI – After the last big freighter of the season went through the Soo Locks earlier this month, a busy window of winter maintenance kicked into high gear for this engineering marvel that moves ships and cargo between Lake Superior and the lower Lake Huron.

The first step: “Dewatering” the Poe Lock, the system’s largest lock – and the only space big enough to handle the 1,000-foot freighters.

Before the Soo Locks reopens on March 25, there will be a flurry of parts inspected and repairs made.  This week, the U.S. Army Corps of Engineers Detroit District shared more than a dozen photos of how their team is tackling the massive job.

Each  year, the locks handle more than 4,500 vessels carrying up to 80 million tons of cargo. Iron ore, limestone and coal make up the bulk of what is coming through on the big freighters.

Of the Soo’s four locks, only the Poe and the MacArthur locks are in regular use in the St. Marys River during the shipping season. Draining those two means pumping out about 73.3 million gallons of water, the Army Corps said. This year, the MacArthur lock was shut down earlier in the season for repairs.

It takes about 22 million gallons of water to raise the level of the Poe Lock by 21 feet when a big ship comes through, the Army Corps said.

While a new lock is planned, the Corps has said it’s imperative to keep the two frequently-used locks in good repair. The Poe Lock is 1,200 feet long, while the smaller MacArthur Lock is 800 feet long.

Below, check out the winter photos and descriptions being shared by the Army Corps.


All photos courtesy of the U.S. Army Corps of Engineers, Detroit District