Yes, heat, humidity and odors (basically air pollution) are a problem in subs. Subs are so awful to live in that the crew always gets the best food and amenitie

Yes, heat, humidity and odors (basically air pollution) are a problem in subs. Subs are so awful to live in that the crew always gets the best food and amenities possible, but before AC I think they worked shirtless. They have layers of insulation for both thermal and acoustic reasons. Subs and torpedos are interesting to study since navies and inventors really struggled to make viable models, and probably a higher percentage of sub pioneers died than in aviation, which is saying something.