I see two really good photos within your picture. Both are vertical crops with the first taking in the left side of the picture (in a 4x5 crop) with the red shirt at the center bottom. The second is the right side of your photo (also a 4x5 vertical proportion) where the red oars are about 1/4 of the way up from the bottom and near the right edge. I think that either of these two would have squelched the comments about being too busy because they would have been concentrating on the beautiful lines within the photograph. Your viewpoint is excellent and the time of day must have been perfect since you captured the ripples in the water so well. The photograph is almost devoid of color but the splashs of red add points of interest. The exposure is quite good with some pure whites and some pure blacks. Although rowing is a sport, it involves a form of transportation just as much as walking, cycling, driving or flying do so I think you met the challenge --- and with a very interesting image.
This is one of the two photos that I rated highest, a 9. The colours and the texture of the water are great, and it's very interesting to see how the various wave patterns propagate.
I like the wakes of the boats - gives a sense of the movment. There are some weird artifacts from processing I think, too much sharpenning? Also a little too busy I'd focus in on the top right and make a vertical composition.