 Still with all the hurdles faced, the Maritime Commission and the yards contracted to it were able to deliver 8 million tons of shipping to the war effort by the end of 1942 and more than 12 million tons in 1943.By the time that Liberty ship construction was reaching its maximum output rate in early 1943, the situation became clear to military planners and the Maritime Commission slowing the rate of the building Liberty class vessels and begin building a class with a higher operating speed was preferable.The decision was made to build a class no larger than the Liberty class, but with steam turbine propulsion, with the shortage of turbines having been relieved by the expansion of turbine manufacturing capacity during 1941 and 1942.