With regards to the photograph of James Arthur Philip Smith. The lighting, along with the shadow to his right, strongly suggests that the photograph was taken outside. He seems to be looking towards the sun and the shadow is at an angle from the same direction. As for the bench looking object behind him, might that be a platform which would enable people to more easily reach the various wheels above it? I agree that it appears to be some sort of gun turret, perhaps anti-aircraft?
His hand does appear to be holding on to the strap of a bag, which, for this spare of the moment shot, he has rested on the deck, without actually letting go of it.
Great picture.