BAM Nuttall will this weekend install a new lock gate at the entrance to the Port of Liverpool as part of a £4.3m refurbishment of the ageing lock system.
The West Inner Gate at the port's Gladstone Lock was re moved this week and will be replaced on Saturday.
Despite the temporary Gladstone Lock closure, over 90% of vessels were able to access berths via the port's Langton Lock during the outage, which started at 7am on Monday morning.
The work has seen the giant West Inner Gate – 16m in height and weighing 400 tonnes – removed following the fixing in place of a limpet dam at the mouth of the lock. The refurbished gate is now being manoeuvred into place and the dam removed.
The operation will be completed by 7am on Saturday, with the first vessel due to pass through the lock at 9am.
David Huck, Peel Ports Mersey's head of operations, said: "The outage is the culmination of many months of planning, and we're delighted that this major feat of engineering is progressing well and is on plan to be to be completed in good time by our contractors BAM Nuttall.
"Our customers were alerted well in advance of the outage and with good planning nine out of 10 of our regular vessel calls have been accommodated using our other lock.
"The completion of the latest phase of these works will provide an even more reliable lock system for our customers, reduce maintenance costs and improve access for our engineering personnel.
"These key assets are essential to the smooth running of the Port. We envisage that these upgrades should ensure the gates are functional for many years to come."
Gladstone Lock's East Inner Gate will be replaced in an identical operation in August taking overall investment in this area of Liverpool's infrastructure to £20m.