We toured the USS Albacore (AGSS 569) in Portland NH and found this placard in the forward Escape Trunk (which doubled as the normal hatch during the sub’s nautical lifetime):
One of my relatives is a submariner who seems calm & collected enough to remember that entire checklist in an emergency.
The heads bore similar placards, along the lines of the classic scene in 2001: A Space Odyssey.
The camera lens they used for their virtual tour pictures would lead you to believe there was actually enough space inside the sub to inhale. That was not the case and I was very glad to have only half a dozen other people touring the sub with us.
Our hotel room (on the top floor of Wentworth by the Sea, egad) had a good view of the Portsmouth Naval Shipard (also see Wikipedia) across the Piscataqua River, where the USS Miami (SSN 775) remains discreetly under cover.