Complex sentence: The trials proved that the class' superfiring main battery was viable in that blast from an upper turret would not injure crewmen in a lower turret, and the ship itself managed to reach on an indicated horsepower (ihp) of 27,212.
Split into simpler sentences: The trials proved that the blast from the class' superfiring upper turrets would not injure crewmen in the lower turrets. The ship itself managed to reach on an indicated horsepower (ihp) of 27,212.