Gilbert and Marshall Islands campaign
Beginning in November 1943, during the Gilbert and Marshall Islands campaign, American submarines were tasked with the rescue of U.S. Navy and Marine airmen downed during aircraft carrier attack operations. Submarines were often vectored to a rescue site by aircraft providing coordinates, but too many layers of command slowed the cooperation considerably. Long-range naval patrol aircraft were fitted with extra radio equipment to allow direct contact with surface and underwater units. By the end of 1944, some 224 airmen had been rescued by submarine.