One could argue they were never gone, but they are back! And this time, panniers are here to stay, I think. They’re a great way to carry a bunch of stuff with a low centre of gravity: why were we angry at racks again? Mounted with Voile straps, they are absolutely rattle free and suitable for off-road use.
They are constructed with a floating liner, which means that water that makes it through the outer seams still is kept away from the contents of the bag. If you need absolute waterproofness you’re better off looking at welded dry bags, but these bags will keep their contents dry in anything but the worst rain.
At 30cm wide and 10cm deep, a minimum rolled height of 30cm gives 9L per side, which you can stretch up to ±13L at max capacity.
I have found a good supplier with a great range of waxed canvas. I will add the options to my website soon, but get in touch if you can’t wait for forward-thinking bags in a time-tested material.