Do they mean in some cases lowering valves? I can see head injuries galore especially for tall crewmen with that.
They were conscious of that problem too.
I think females on submarines is a terrible idea. When I was on a Carrier, a lot of them got pregnant, and weren’t available for deployment. That problem is magnified on a submarine because of the smaller crew. If one crew member, especially from the Engineering department, can’t make movement, it gets very hard to make the watchbill, and you would have to take a guy from another boat.