Wow. I spent 20 years in Uncle Sam’s Undewater Canoe Club and the thought of claustrophobia never once occurred to me. I’m clasutrophopic just looking at that picture.
No fooling. I for one would be happy to point out that I couldn’t fit through the hatch, so you’ll have to get another volunteer...
I was the skinniest qualified QA inspector on board. Every tank, void and impossibly tight squeeze on the boat has a corresponding document in a warehouse somewhere with my signature on it.