I'm buying an IBC in the morning.......and i'm totally intrigued as to what baffles are.....I'm baffled
I suspect they're a device to stop water sloshing about too much.
Imagine you've got 600 liters (= 600 kg) of water in a 1000 liter tank, in the rear of your van. You're travelling at 40 miles per hour and have to brake sharply; all that water will rush forward and the forward momentum of it would not be pleasant.
The baffles reduce the 'slosh effect' I think.
(With that high-brow explanation, can you tell I have O Level physics (Grade C)?)