Does anyone have any idea what color the exterior of the pressure hull on the Type VIIC/41s were painted? I am in the preparatory stages of building one of the Revell Germany 1/72 Type VIIC/41s. I am in the process of drilling out the flooding holes and will install one of the Yankee Modelworks resin pressure hull tops. I realize that little of it will actually be seen, but short of painting it charcoal gray (guaranteeing it won't be seen), I'd like to be as accurate as possible in my color selection. I'm considering painting it primer red. Would that be completely off base? I've read Dougie Martindale's monograph on U-Boat colors, but it unfortunately doesn't address this question. Thanks in advance for any help!