A common misconception is that the early 688's could rotate their fairwater planes 90 degrees to surface through tthe ice. This isn not true, the 688's with fairwaters did not have hardened sails or 90 degree fairwaters, and were not capable to surface through the ice unless it was an emergency, then the max limit was less than 4 feet of ice, and they could do it one time. The ringed props on the Improved LA's was for more than ice ops also, would tell you about it, but then I would have to kill you
I was one half of the two person team trained to surface the boat through the Ice in an emergency when I was on the USS Augusta SSN-710. The Chief of the Watch (COW) and the Diving Officer of the Watch, I was the COW, but was trained as the DIve also, the whole show was pretty much the COW. Very interesting training, and many hours in the Dive and Drive simulator at sub school.
ETC(SS), former IC man, COW/DOOW God, EOG Lectec master, Electrical A-ganger, and general pain in Bill's hindquarters
When surfaced, the bridge access hatch can be optionally open or shut, however, when submerged it is required to be shut. (Really a no s***t precaution from a procedure in use in the sub fleet today.)