When the tankers were Whitakers we once spent some time with Humber Princess working the Don section from Sprtoborough to Rotherham. We had the C&RT Harbourmaster with us. Yes they have a Harbourmaster as they are a port authority, just like the big boys, port of London, ABP etc. They have their own regulations (not col-regs but mostly similar) etc.
Barges normally work 0600 - 2100 but not in the dark. You can feel the disturbance 15 to 20 minutes before she arrives. On the main lines where they run always moor to bollards or rings and use spring lines. Centre ropes should never be used.
The tankers have a GPS recorder fitted and can verify their speed at any location if a claim is made.