I'm not sure but I do know that it is more like gallons per mile. But due to the immense amount of cargo it is still an inexpensive way to transport goods.
Usually the consumption is given in barrels or tons pr day, because the consumption is very dependent on the vessels speed.
380
The number of stops a cargo ship will make depends on how much cargo the ship has and how many places it has to deliver cargo.
1 deck
sleep
around 30
1000
the cargo hold
a cargo hold
45
Container ship.
a cargo hold
The Cargo must weigh less than the ship, and although heavy, ships are less dense than water.