She's a member of our armed forces so why shouldnt she serve on a boat? Its part of her job which she knew when she enlisted and when she had her child that there was a chance she would be assigned to a boat and so have to leave her child and husband at home for 3/6 months or whatever it is. Women have been going to war for years so why not?
http://en.wikipedia.org/wiki/Florence_Nightingale