The was the first nuclear-powered submarine. "Nautilus" put to sea for the first time on 17 January 1955, transmitting the historic message, ""Under way on nuclear power."" Up until that point, submarines had been torpedo boats tied to the surface by the need to charge their batteries using diesel engines relatively often. The nuclear power plant of the "Nautilus" meant that the boat could stay underwater for literally months at a time, the only operational limit being the amount of food that the boat could carry. With resupply by mini-subs, even this could be overcome. The final limits would be for replacing equipment that wears out, the fatigue limit of the hull, and crew morale.