Hiryu resembled Soryu but differed enough in construction to be treated as a separate class. She displaced about 17,600 tons and combined 153,000 shaft horsepower with capacity for sixty-four operational aircraft and nine spares. Those figures make Hiryu slightly larger and marginally more capacious than Soryu. The comparison explains why the two Midway carriers are close developments rather than interchangeable sister ships.
Notable Point · 23:30-24:06
Hiryu diverges from her near-sister Soryu
Hiryu's displacement, power, and aircraft figures show why she and Soryu are often treated as related but separate carrier classes.