ASHLAND CITY, Tenn. (July 29, 2022)— Nashville District engineers reset upper approach stop logs on Cheatham Lock in Ashland City, TN. Engineers from the USACE Huntington District Light Capacity Fleet assisted with the maintenance work completed July 25.
Engineers previously performed maintenance on the lock by replacing some lock filling valves and emptying valves. During this routine maintenance, some of the lock gate’s j-seals were replaced, which will help prevent leaks and help keep the structure up to date.
Lock and Dam Equipment Mechanic Supervisor Justin Gray said there weren’t any problems with the gate, but it’s been a long time since the seals received maintenance it’s better to conduct the routine maintenance now while they had the chance.
“The seals hadn’t been replaced since the mid-1990s, so it was time for a replacement and some updating to more modern parts,” said Gray.
The massive stop logs were pulled from the lock weeks prior, and the old seals were removed before the maintenance and resetting process.
“Six stop logs were reset. Two 84,000-pound stop logs and four 63,000-pound stop logs. We replaced each stop log, one at a time. We set the upper closure stop logs to replace the lock gate seals and prevent any future leakage,” Gray said.
The maintenance helps ensure the upper lock gate seals off water when closed and prevents cavitation, the static pressure of water leading to the formation of small vapor-filled cavities.
Engineers from the USACE Underwater Diving Program dove into the water to unhook the stop logs from the massive 348 Crawler Crane which can tow a maximum of 300 tons. Once detached, the logs are secured, and the next log is ready to be set on top.
Nashville District Dive Coordinator Kyle Tanner said the diving team prepared to set the stop logs by first sweeping the barrier surface in advance. The team ensured there was no debris in the sealing area which could interfere with the proper seal.
“The dive team comes to set up, get everything prepped and ready for maintenance. We do things like setting stop logs, bulkheads, and pumps. Pretty much anything that requires major maintenance, you can see the dive team at the forefront assisting where we are needed,” said Tanner.
Once engineers lowered and set a stop log, divers dove underwater to verify the stop log was flush and had a proper bearing surface. Divers then unrigged the stop log from the block of the crane and verified the next stop log could be easily placed.
“Out of the six-stop logs, four are placed under water. All four require divers to help remove and reset the stop logs. Its important divers are here to help with this part because you really can’t do it without the proper equipment and training,” said Tanner.
Jesse Watson, a welder from the Huntington District based out of Louisville, Kentucky, said performing routine maintenance on the lock ensures the lock and dam are functioning properly and vessels can travel the waterway with no delays.
“The seals are now replaced, and the gate continues to function well. We won’t need to do any maintenance like this for a long time to come, but it’s good we got it taken care of before we were forced to replace anything from damage,” said Gray.
The Corps of Engineers has several maintenance projects currently taking place. Huntington District engineers will be heading to their next project in the Louisville District shortly after leaving Cheatham Lock.
“We enjoy being part of these maintenance operations throughout the Corps. Almost every project requires a dive operation because most of these infrastructures weren’t designed for maintenance above water, so it requires a dive team to assist,” said Watson.
(The public can obtain news, updates and information from the U.S. Army Corps of Engineers Nashville District on the district’s website at www.lrn.usace.army.mil, on Facebook at http://www.facebook.com/nashvillecorps and on Twitter at http://www.twitter.com/nashvillecorps.)