Steam tug won't dock at the tug dock

[belleofthesea]

I'm not sure if I have set it up wrong, but no matter what I try my steam tug won't dock at the tug dock. I check the Little Logistics website and watched YouTube videos, but haven't found anything referencing this specifically as an issue.

I have a steam tug with two fishing barges and a chest barge. The tug doesn't dock so the barge will not unload into hoppers unless it's disconnected from the tug.

Any help with this issue would be greatly appreciated.