The Type 91 aerial torpedo was more than an effortless special weapon. Anti-roll devices helped prevent it from twisting off line in the air, while extended fins improved stability and controlled the water entry. Ordinary shallow-water adaptation still differed from the extremely shallow launch conditions required inside Pearl Harbor. Aircraft under fire could not maintain a perfectly level approach, so small changes in release attitude threatened a bad entry angle. Weapon engineering, pilot technique, and target geography all had to work together for the strike to succeed.
Notable Point · 55:41-58:08
Adapting torpedoes for Pearl Harbor's shallow water
The first-wave B5N attack illustrates the engineering challenge of keeping an air-dropped torpedo stable and shallow enough for Pearl Harbor.