By the way, hatch#7 might be sifted starboard in her career. But I can not find when it was.
A : Hatch#7(probably original, but sealed with a steel plate with rivets) , B : Large opening (sealed with a steel plate with welding ), C : Curved beam for B.
Present Museum Mikasa. Around B & C.
Another problem is shape of forward ventilators of the engine room. There are two different sketches of them.