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Making an Impossible Blockade of Nazi Ships Possible

In late 1943, the U.S. Navy received word that five German freighters would be steaming up through the South Atlantic. They were loaded with enough tin and rubber from Asia to meet the needs of the Nazi war machine for another 18 months. They had to be stopped. The task of devising a blockade to cover the width of the ocean fell to a Ph.D. chemist named Jacinto “Jay” Steinhardt, sent by the Antisubmarine Warfare Operations Research Group to Fourth Fleet headquarters in Recife, Brazil.

The Navy could assign fewer than a dozen planes to the effort, roughly half from Brazil and half from Ascension Island, 1450 miles away. It was a swath of ocean as wide as the gap between New York and Dallas. But Steinhardt was steeped in ASWORG’s search theory and had been calculating search plans that had sunk U-boats off the shores of South America. Flying a strict schedule and flight pattern, Navy planes spotted all five of the blockade-running freighters. Three were sunk in as many days in January 1944, the Fourth Fleet “Triple Play.”

Rear Admiral C.E. Weakley later called Steinhardt’s contribution “tremendous,” in devising a plan, “by which an apparently impossible, small number of air searches and small number of surface ships blocked the Atlantic completely to the German blockade runners.” Steinhardt went on to lead the organization that would become CNA for almost two decades.