How would Britain handle the Imperial Japanese Navy's submarine fleet?
Short answerThe Royal Navy would rely on its established anti-submarine doctrine: ASDIC-equipped destroyers around task groups, supported by Swordfish patrols and continuous carrier-based air cover.
NotesJapanese emphasis on attacking warships meets a British fleet organized around anti-submarine screening. Destroyers use ASDIC around the task group while carrier aircraft maintain both fighter cover and anti-submarine patrols. Swordfish can search beyond the destroyer screen and force a submarine to spend more time submerged or evade instead of setting up an attack. Persistent carrier operations therefore remain valuable even when no fleet air strike is underway.