That seems to be the problem with the King George V lock in London’s Royal docks.
Galloper then returned again a few days ago but it appears that there were still some raised areas of silt that could hamper the safe passage of vessels through the lock.
As a result further work was required and so the marine dredging company Van Oord sent their shiny new water injection dredger Borr to help clean up the Royal Docks.
This is a video of Borr in action:
A few more pictures of Borr can be seen here.