 So they're using large, they're called clam buckets, and they're grabbing mud from the bottom, and they're putting it into these barges. Mud and gunk, and we keep waiting for it to pick up a car or something. We voyage further through Houston's industrial underbelly. Captain Genaro Ambriz points to a petroleum product storage facility. Well, there's actually a refinery here on this side. We pass several very large ships, including one called the Seaways Hercules.