Nicely spotted, but I feel that perhaps the cityscape behind draws one's attention away from the lines that should be leading one in to the subject. Have you tried cropping down from the top to the roofline, or thereabouts, of the houses?
very interesting pic. you cover a tremendous amount of ground in it, between fore, middle, and back. unfortunately they each feel very distinct to me and it doesn't feel like it meets a leading line challenge as your subject to my eye is the big building in the middle ground. nonetheless, i really like your choice of toning.
Leading lines or curves generally have two purposes. One is to lead the viewer into the scene. The other is to lead you toward the main subject. It is most effective if they come in from the lower left because that is the natural direction humans visually scan a picture from so are easiest to pick up.
Your have nice lines leading to the boater but not to the skyline that takes up most of the frame.