Early war submarine paint and weathering question

Modeling Subjects Ships
1

I’m bulding my 1/72 Revell Gato as the Tambor class USS Tautog as she was at the time of the Pearl Harbor attack. I know early war subs were overall flat black and I have here an image (from Navsource) of the USS Trout, also a Tambor Class boat (from a different yard), as she was in March of 1942.

USS Trout

I want to use this and other images of the Trout as a weathering guide and was wondering what I should use as an undercoat that would be exposed from the pealing black paint. Would the exposed areas be a gray undercoat or exposed steel? I’m leaning towards gray paint. Opinions?

2

Since the sub was delivered in black, not gray [photo # 0820205] – I would bet that the light patches are Yellow Zinc Chromate, not gray. Steel would be running rust in the salt environment

3

Thanks, Ed.