Not only ice cream but

[joea]

Regular baths according to this link:

http://www.bowfin.org/website/bowfin...ater/water.htm

Fresh water is vital on board a submarine not only for drinking, cooking, and washing, but also for storage batteries, boilers, and as a cooling agent for the diesel engines. An American World War II submarine on a war patrol required a minimum of 600 gallons of fresh water a day. Beyond this, remaining water supplies should leave enough for each man in the crew to have a bath at least twice a week. Cooks were normally required to bathe every day, for obvious reasons.

Well thank goodness, I guess.