I don't suppose you have ever thought about how to fill up your ferry with fuel ?
It's not that easy to just sail down to your local BP or Shell forecourt and pump in a few gallons of best four-star !!
Here is one answer, you just drive a fuel tanker straight on to the car deck and pump the diesel into the ferry.
Easy !
Taken while waiting for this ferry to take me over to the Isle of Shapinsay from Kirkwall.