Photos show inside the empty 1,200-foot-long lock at the Soo Locks

Posted at 3:43 PM, Jan 29, 2020
and last updated 2020-01-29 15:43:07-05

The U.S. Army Corps of Engineers this month is working to maintain the Poe Lock at the Soo Locks, and new photos show inside the largest lock while it was empty.

In a post on Facebook, the Corps said the last freighter of the 2019 season came through the Poe Lock on Jan. 15, and crews began to dewater the lock for a busy maintenance season.

According to the Army, the Poe Lock was completed in 1968 and is 1,200 feet long, 110 feet wide and 32 feet deep.

"The Poe Lock holds back a head of 21.5 feet (the difference between normal upper pool and normal lower pool). The reinforced concrete floor and monolithic concrete walls are constructed on a sandstone bedrock foundation," the Army said on its website. "The monolithic walls each contain a service gallery and a filling/emptying culvert. The gates are steel, miter type with direct connect hydraulic cylinder operation."

It's the only lock capable of locking the massive 1,000-foot freighters, ad was constructed at the site of an earlier Poe Lock, completed in 1896, and the old State Lock.

Check out the photos below.

Shortly after the last freighter for the season left the lock, crews moved cranes and barges into the lock to begin setting stop logs (steel bulkheads) at the upper end.

Using the new heavy lift crane on a floating platform, eight stop logs are set into place to create a temporary dam at the upper end of the lock. Each log spans the 110 foot wide canal and weighs about 50 tons.

Workers remain in constant contact with the crane operator as the logs are lowered into slots in the lock walls. Crews on both sides of the canal ensure that the logs descend evenly to prevent them from sticking.
After setting the stop logs, the crane moved East in the lock to set a temporary bridge across the Poe Lock.
Workers help guide the bridge into position. Having temporary bridges across the MacArthur and Poe Locks has allowed more flexible use of heavy equipment during lock maintenance. Without the bridges, all equipment had to be delivered by barge before dewatering the lock and could not be removed or used elsewhere on the facility until spring.

The Detroit District Dive Team plays an important role in dewatering the lock. Divers hook up bubbler systems and chink leaks between the stop logs.

With water temperatures around 34 degrees, divers were comfortable working in dry suits but on the surface tenders braved 18 degree air temperatures with the windchill making it feel like 1 degree.

The final dewatering task for the heavy lift crane is setting stop logs across the lower end of the lock. These logs, like the ones at the upper end, weigh about 50 tons each and will span the 110 foot wide canal. The crane will spend the winter at the lower end providing lifting support to crews working on the lock floor.

As the log is lowered into the water a worker on each side holds a sounding line to monitor the depth of the log. This way even when the log is out of sight they can ensure it is sinking evenly and verify when it has reached bottom.

As the log is lowered into the water a worker on each side holds a sounding line to monitor the depth of the log. This way even when the log is out of sight they can ensure it is sinking evenly and verify when it has reached bottom.

A view of the dewatered Poe Lock taken from the upper stop logs. Despite a snow storm crews were busy laying up the lock and staging equipment for the busy maintenance season.
A crane lowers equipment to the lock floor.
A view of the lower gates from the lock floor. Each gate is 57 feet tall and weighs 225 tons.