This is definitely a more complex version of a Decisive Moment.
Complex is not the same are complicated because there is nothing complicated in this image. But it is, in my view, complex both visually and related to content. The share number of themes working together have increased when comparing this image to the other example of a Decisive Moment: Come Fly With Me.
The viewer will automatically ask for these many themes to work together for is to build a coherent image in his/her mind. I my view they do, but you don’t have to agree in this.
Let me point to the possible sub themes in the image: the sunbathers and black dog looking out towards the canal; the man in the foreground also turning the back on the sunbathers; the sunbathers themselves; the dog and the man both turning their backs on the sunbathers; and, of course, the curious guy in the boat close to the frame at the left hand side.
What is happening here? That is the question. Is this a random constellation of people, or are there more subtle issues at stake here? Perhaps the whole thing is an act in a play unfolding at the dock of the bay. Hardly.
I am not going to suggest what all of this means, because meaning in a complex moment like this is very much up to the individual to speculate about. And with that I will leave it.
If possible: Enjoy.