Although I agree it looks more like sloppy modeling, I don't really see a better solution for the time being. The sides will in any case be cluttered by dredge material and the bottom will have the plate with dredge material on top, so little will eventually be visible in there.
Bare metal doesn't really exist at sea, when a steel surface is exposed in a sea environment, it takes about 30 minutes - 1hr before it turns completely orange.
So for maintenance purposes at sea, when a deck is chipped of rust and the primer is not immediately applied, it has to be brushed again with a wire brush before you put the primer.
The hopper of these ships was, even at new building stage, never really painted and already had the rusty brown appearance of the steel they used. Only the top appears to have had a white sort of primer and then the black/anthracite.
Made some progress on the walkway, I'm using one half as the experiment before I continue on the second half. I cursed myself for even trying to use PE. Very flimsy, but I guess it's an excellent quality due to its fine nature.
The PE I use is from Aber, 1/400 railing, 1/400 stairs and I also have 1/400 slanted railing. I use the slanted railing for the stairs, but in reality railing on stairs isn't like this... I also tried to use it on the slanted part of the hull, but the angle is wrong and I had hoped to bend it to the correct angle, but this can't be done.
The railing is supposed to be drilled, with a jig for drilling the holes, being incorporated in the side of the PE fret. However this only allows for drilling straight lines. The advantage for my build, is the railing has small extensions at the bottom to put inside those drilled holes, this extension is nice to stick to the side of the catwalks.
I'm still figuring out how to work with this PE, so quality is inconsistent. I do try to put the yellow steps at the top and bottom of each stair as it brings some life to the moss green.