All SSN's fwd are 1 in 2, it was the only "culture shock" I had when I finally escaped from back aft and went wrecker.Perk of being a bomber queen (middle bit) is that we were 1 in 3 so could have our daily beer ration when under way so no worries about the long life milk! Back afties and ourselves used to have one or two sociable drinks after the first.
Never understood why they made the control room team 1 in 2 on bombers when they had more than enough people to go at least 1 in 3 with cover available for comfort breaks etc. Often resulted in someone doing SCOOW for 1 hour out of 6! As for work up, poor buggers doing the long middle were completely knackered as they would only realistically get time to sleep between 7pm and midnight.