March 1943 – Derby House, Liverpool.
Nineteen-year-old Janet Patricia Okell stood over a chalk-marked floor in the freezing basement of the Western Approaches Tactical Unit. Admirals brushed her off. Officers doubted her. But Janet knew something they didn’t: British convoy tactics were failing — and the math proved it. Worse, those same tactics had just killed her brother in the North Atlantic.
https://www.youtube.com/watch?v=_LDE9z9ZQiE
