A Few Comments Regarding US Ship Propulsion
Industrial production considerations dictated the choice of propulsion plants in US shipbuilding in World War 2. Throughout the war, as a result of insufficient production facilities, there was a comparative shortage of reduction gearing for steam turbines, which were needed for just about every type of surface ship, and diesel engines, which were needed for submarines, DE's, landing craft, minesweepers, patrol craft, several types of fleet auxiliaries, as well as locomotives. This manifested itself in a number of ways.
One is the variety of propulsion systems and DE classes. Although the DEs tended to be designed for speeds in the 24-26 kt range, with many of them, a powerplant of the appropriate power wasn't available and a less powerful plant had to be substituted. The shortages can also be seen in the variety of plants used, as depending on the class, a DE could have a diesel-electric, geared turbine, diesel, or turbo-electric powerplant, and to introduce further variation, there was a short-hull design with the diesel plant, and a series of long-hull designs which could have any of the plants, and either 3x3"/50 or 2x5"/38 guns. Friedman's book on US destroyers goes into some detail on this.
Another is the choice of reciprocating engines for the Liberty Ships & the Casablanca-class CVE by the Maritime Commission, which did much of the design work for both classes. The Maritime Commission was aware of the shortage of geared turbines & diesels, and searched for an engine that was not in great demand anywhere else, simple to install using the unskilled labor at the Kaiser Shipyards, and would also be fairly simple and reliable so that a relatively inexperienced crew of hastily-trained wartime enlistees could operate them effectively. These considerations led them to the Skinner Uniflow reciprocating engine, which was considered adequate for the tasks put upon it.
There are also some comments regarding the diesel-powered CVEs converted from C3 freighters in both US & British service in Friedman's book on US carriers that suggest that the diesel C3 had some issues, particularly when it came to sustained high-speed cruising. Both navies found these ships to be slower than expected and suffered from some mechanical reliability issues, which, combined with the production issues, led to the remaining C3 conversions being of steam-turbine ships, and the choice of the reciprocating engines for the Casablancas.