Reminds me of the Hunley. Far better tech, but similar in appearance.
I don’t know why, but just yesterday I was thinking of the “Hunley” and the bravery of the men who volunteered to deploy on her. Just amazing! I nearly got my claustrophobia in gear just by looking at that graphic you responded to. Yipes! I could never go into any sort of submersible, no matter how large.