A few minutes of good harassment can sort out who are the girly men really quickly.
During my last 3 years of active Naval Reserve, I was part of the recruiting team. My main job in a maximum of 10-15 minutes was to weed out the weak, druggies, fakes and criminals to lighten the load of the people doing the full background checks. I had their test scores and their brief life history to look at. I had a few questions to start with like your welcome to the boat. It was amazing how many were weeded out in a few minutes. Shipmates did not want a cry baby with them on a ship and in a GQ situation.
One of the things that folks don't get is that the really smart guys on submarines are not the officers, but the rated enlisted. These are guys who scored in the 99th percentile on their ASVABs. I was convinced that the real challenge was that a lot of them were juvenile delinquents, but were too smart to get caught, and I had to put up with it for months at a time underwater. The antics were classic.