Axis submarines operated in the same Far Eastern waters without a sufficiently integrated identification system. Because a detected submarine might be an ally, Axis forces could not freely prosecute every underwater contact. The resulting fear of fratricide weakened anti-submarine action. British submarines in the Indian Ocean could exploit that coalition-coordination failure and operate as predators among forces reluctant to shoot.
Notable Point · 2:48:43-2:49:06
How Axis submarine coordination aided British submarines
German, Italian, and Japanese submarines sharing waters created a recognition problem that discouraged attacks on submarines and opened space for British boats.