It was my intention when taking the shot to include the IMO, but discovered it was obscured by a mooring rope.

IMO 8658889. This Ship IMO Number has been given the current ship name SVITZER ARK. It carries the flag of SWEDEN

In fact, SVITZER ARK is marked as having a vessel type of "DECK CARGO PONTOON".
The hull of boat 8658889 (SVITZER ARK) is made of metal/steel and was manufactured by WUJIAZUI SHIPBUILDING - NANJING, CHINA in 2008. The vessel has a gross tonnage of 1156 tons and a dead weight of2790 tons.
IMO Number: 8658889 had previousboat name (BOABARGE 41 until 2012 Nov).

Almost 3000 non-propelled barges of one sort or another have been allocated LR/IMO numbers. Some of those will have been at owner's/builder's request, but I suspect that a large proportion are only because they were built to Lloyd's Register Class and it is a common numbering system. If they drop out of LR class, they tend to disappear from current listings, though of course the LR/IMO number still notionally stick to them for life.

I find it strange that a barge can have an IMO number assigned to it, don't you ?