There are ships being launched from Swans and a view of Hebburn can be seen.
On photo interested me, the Mauretania in dock with a view of propellers.
The forward two are 4 blades the stern two are 3 blades.
The design of the forward and stern props have different shape of blades. This is because the stern pair run in turbulent water from the forward two. Fluid dynamics these days.
I suspect that this photo may have been taken on her docking after her sea trials, why. There seems to be a Nick in one of the blades to the starboard stern prop.
My interest is because of all the diving that I did on shipwrecks, unfortunately the big wrecks in Scapa Flow had had their props removed between the Wars.