[RSwank]

What is the spacing on a row of rivets? Is the distance between two rivets an "even" metric distance or does it come out to be an "even" inch or fractions of inch distance? I assume we are looking through 6 plexi-glass "panels". I am thinking this would be a "top" escape hatch or part of the hatch. Does it appear the hatch was originally "curved" or was it quite flat. It is hard to tell from the photos.