The shallow-water torpedo knowledge Britain did not share

The wartime Allies shared naval-air information, although cooperation had limits. British experiments combined a tension wire, extended wooden fins, buoyancy calculations, and repeated testing so an aerial torpedo would enter shallow water without diving too deeply. That specific method was not passed to the United States. Japan did not receive it either, a fact with obvious later relevance to Pearl Harbor. Broad alliance learning stopped short of transferring every operationally decisive technical method.