It was a bit of a happy accident. When I had the drawing halfway done, I noticed that I could not use ink washes to represent rust on the flimsy 80g paper I’ve used. I tried it with very little water, but the paper instantly warped. Then I tried to show the rust by drawing the outlines of rusty areas, but that didn’t look very convincing. It worked better with smaller outlines, so I tried it with single dots. This looked much more like the rusty pock marks on the hull.