A little tip from a prototypical tugboat captain. In this situation, you would not have any white water along the sides of the barge, nor on the sides of the tug. Behind the tug, you will see alot of white water.
After the tug gets the float notched up to the ramp, it pushes hard to help hold the barge in the notch to keep the loco from pushing it away from the ramp. There are cables that are strung from the barge to the dock to hold it but they are usualy not strong enough by themselves to resist the push of the loco.
Since the barge is not moving, nor is the tug, there would be only white water at the stern of the tug from the wheel wash, and it would be considerable.
Try adding some details to the barge. Barges almost always have a double post on each corner. This is called a bollard. Spaced along the sides of the deck of the barge just farther apart than the tug is long, are cavels. These are what you are used to seeing as cleats on small boats. Just one heck of a lot bigger. About three feet long, and 6 to 8" tall. The lines from the tug will be one leading forward from the bow of the tug. One leading aft from the quarter bit on the tug, and one from the stern of the tug to the bollards on the corner.
Another detail you could add is the running lights on the barge. The bow of the float is the end at the stern of the tug. The left side light is red, the right side is green. In the center of the stern of the float would be a white light. If my description leaves you in the dark, let me know and I'll try to draw up pic of the details.
Great idea, and nice execution. Lets see some more pictures when you have it finished.
