What do you call a couple of barges tied-up?

I haven't a clue! Perhaps, A Berth of Barges?

"Nothing special about a Berth of Barges" you may say! But these are not on a canal they are in Liverpool's Albert Dock; two minutes from the River Mersey and the Open Sea - they "sailed" here under their own "steam" - not bad for barges! Just like they did hundreds of years ago.