I'll try to be specific.
Tug boats are interesting. Bridges are also interesting. But together the image is flat.
Bridges are usually interesting because of the patterns, structure, and high contrast. Usually something with interesting patterns, texture, structure, patterns, and rhythm would be a great subject to shoot in black & white. The tug is also a bit soft, the background is a distraction, there's a lot of noise in the image and the saturation looks like it was boosted. So we can't quite see any crisp detail in the tug. The overall image has a lot of mid-tones which generally contributes to the flatness of the image.
Don't give up. Keep shooting. I admire that you're wiling to get up early to shoot during the dawn golden-hour (even though this particular day was heavily overcast.)
You didn't post any exposure info and there's no EXIF data. Based on the fact that the water motion is frozen (I'm looking at the water breaking at the bow) I'm guessing you used a shutter speed of at least 1/250th or above. Use a tripod, "pan" the boat (use a tripod if you must) with a lower shutter speed, go ahead and let the water blur out. Drop the ISO to reduce the noise in the exposure. I'm not sure what f-stop you used - it might have been excessive.