What color should a Schnorkel be? Should it match the color of the upper hull or is it some sort of metallic color? Does anyone know whether it was made of metal or stainless steel? Since smoke was coming out of it, I would assume it had some smoke stains on it as well?
Thanks!

Thought 1.... Why would smoke come out of it? It's purpose was to allow ship to remain underwater and be able to get air. ANy smoke would be from crew smoking inside of ship or sometning like that which would be extrmely minimal.

Thought 2... I would go with ships color as it remained folded up on the deck until deployment.

From what I understand, the schnorkel served as an exhaust valve as well as an intake to keep the diesels running while submerged...

I believe you are absoluely right, I stand corrected.