The Italian Trento class works like it should

Since I have long been interested in fast ships, I naturally took an interest in the Italian cruisers from 1925 to 1943. I just ran the Trento class heavy cruiser design through my program, and "it works". It works in the sense that for 150,000 SHP, the speed is 35 knots. That's at the normal displacement of 13,114 tons given on the Italian navy website. My deep load speed is 33.6 knots. I was never that sure that the nominal speed (35 knots) was actually a good number, but I can see that it is feasible. Admittedly, that is with a propulsion efficiency of 0.53. The coefficients that I used are Cp=0.536 and Cm=0.88. If the Cp were 0.61, it could make 36 knots. That is actually the speed they were said to have in the Conway's book, All the World's Fighting Ships 1922-1946.