Interesting shot, worth the taking.
Have you tried looking at a black & white version? There's so little colour present, it may work well.
The yacht doesn't worry me, but I do wonder if the right hand side can be bought in a little - the cut off boat adds little, though the Stena Line Ferry(?) and tall building do seem right for the composition.
I suspect at these sort of distances you would still not blur much of the background even at F1.8 aperture - you would want to be much closer to the subject (and here, lose the composition). I'm out of my depth (Hah!) in this, but various online tools should give you the start and finish of the depth of field at this sort of distance for your lens and camera, and you obviously want things to be blurred to be a long way (proportionally) out of that range. https://www.photopills.com/articles/depth-of-field-guide might be a place to start, but there may well be better, or better suited to you.