The 15.000hp is accurate as it is written on the pages (more will follow). Maybe it is per shaft so if we think 4 shafts that is 60.000shp Yes germans are known for their WW2 hybrid battlecarriers.
Ever heard of the Anglo-Japanese naval treaty? Before WW2 or more precise before the ultra nationalists got to power in Japan, the IJN and the RN had close ties. Many naval architects and admirals could speak English and many WW1 and pre WW1 IJN ships are built in British shipyards. Such as the IJN Kongo, the Katori class battleships etc etc
