fwiw i haven't tried it, but the swig is very similar construction but a flap instead of a rolltop. they are not waterproof in terms of holding water. the maverick line is seam welded so that should be waterproof, but i have no clue if the interior seams are seam welded as well. both are meant to keep water out, not keep water in, so if you want a backpack you can fill with ice i don't think these are your best options.