ok-- were off food and on to garbage..
a scow is a flat bottomed boat.. (think of a barge) and it is pushed by a tug boat. (but it used to be poled..)
and while a scow can carry sand or coal, or any such thing, it somehow got associated with garbage. so you have barges full of commodeties, but scows full of garbage..

meanwhile the mess hall, is just a contraction of comestibles. --crossing threads, my favorite food? anything comestible!