Naval Service of Jimmy Carter
President Carter spent a little less than four years in subs. The entry requirements are no doubt tough but the duty is among the cushiest in the Navy.
Carter was selected by Rickover himself, and though I agree sub life now is cushy, it wasnt back when he served.
You're right about the time when he served. Someone earlier stated he served 11 years in submarines. I count a little less than four and then he did whatever Rickover had him do. Carter was a smart man but did not do 11 years in subs.