That appears to be an ITB (Integrated Tug Barge) not an ATB (Articulated). The “tug” and “barge” are completely locked in and move as one unit in all axes. There used to be a bunch in the US fleet but they were eventually required to be manned the same as a similarly sized ship and the economic advantages were lost.
An ATB will allow independent motion in the pitch axis (ie, articulating about the pins) but the tug and barge are locked together otherwise. These units, especially the ones that are conversions, are more in line with conventional tugs and barges. Even the purpose-built ones have tugs that are more “boaty” than the ones on ITBs and, in theory, could tow the barge in an emergency. Whether that’s actually true or not is another discussion…
ATB is an industry term, not a legal one. The confusion of terminology is confounded by the fact that the CFRs refer to Dual Mode and Push Mode ITBs. An ATB is the former, but not the latter (at least as far as the law goes).
EDIT: I stand corrected. Upon closer look, I do see pins and ladders in the notch. May very well be an ATB.
The two tugs ‘Ursa Minor’ and ‘Ursa Major’, and the barges, are owned by the huge steel producer ArcelorMittal. They transport exclusively steel-coils from the steel mill in Taranto to Italy’s industrial north, either to Genoa or to Ravenna (Adriatic Sea).
It takes some time to load/offload the heavy coils from/to rail cars. Meanwhile the tug can push another barge, ready to go north or south. This seems to work well.
Some six years ago the ‘Ursa Major’ had a heavy engine room fire, extended up to the bridge. All was rebuilt >>>
There was a study done on the feasibility of using one tug and three barges for a relatively short sea passage with forest products in NZ. At the time the sea states that could be encountered were outside the perimeters of the locking system but I imagine there has been major improvements over the last 30 years.