I did 13 hours fouled on the bottom once, after a 7 hour mission. What I was wishing for was a large glass of whiskey and a hot shower. 72 hours? We have to ask the two Rogers about that. They did 80+ hours and were mostly zonked from cold and fatigue and plain old boredom (not to mention nearly zero O2 and being scared shirtless if they'd had the energy). Vance