The aircraft was not a first-rate conventional bomber; its range and the possibility of operating without recovery floats mattered more. Three or six aircraft from one or two submarines could carry torpedoes or heavy bombs against a refinery or similar target, where fire and interruption could exceed the apparent weight of the raid. Pairing the I-400 force with equally long-ranged minelaying submarines would make critical ports face air attack and mines at the same time. The United States would then have had to spread radar, fighters, patrol aircraft, and destroyers across an enormous coastline. Britain's Chain Home system offers a sense of that burden, which could extend beyond the West Coast to the East Coast, Panama Canal Zone, and approaches through Mexico or Canada. Ditching the aircraft or assigning a one-way mission could extend reach further, making recoverability another variable in target selection.
Chapter · 22:48-30:11
What the Seiran strike aircraft could threaten
The Seiran's value lay in range and target selection: a small air group could still start damaging fires at hard-to-defend coastal infrastructure.