The short documentary I just looked at had the same credits as the IMDb listing. It's just that the IMDb plot summary is completely different. I have tried to change these in the past, to no avail, so I will describe what I saw here.
This is a one-reel documentary about Liverpool's docks and the estuary that makes it a great port: the Mersey. It begins at the docks, with the ships steaming in, and dockworkers on display, then discusses the Mersey, from its origins in the Dorset hills down to Liverpool. We see more docworkers, then the ships steam out.
S.D. Onions' camerawork is good, if rather standard for such documentaries. What I found notable and ultimately annoying, is the commentary written by Bill Duncalf. The man seems to have never met an adjective he didn't like, and tries to put as many of them as possible -- plus a few more -- into the mouth of commentator Lionel Gamlin. Even with that, there are stretches when the speaker is quiet, and so that time must be filled not only with the loud noises of the port, but a strident and dramatic score. Could they have been paid by the word?