In the winter of 1942, the U.S. Navy faced a problem it had spent two decades ignoring. German U-boats were sinking merchant tonnage faster than American shipyards could replace it. The Eastern Seaboard ran dark while cities extinguished their coastal lights and tankers burned offshore, visible from the beaches of New Jersey to the Outer Banks. Admiral King's reluctance to adopt the convoy system had cost the Allied cause nearly five hundred thousand tons of shipping in the first three months of the year alone.
The Arithmetic of Protection
A convoy is not a formation. It is a system that depends less on the firepower of its escorts than on the discipline of its merchant masters. The geometry is unforgiving: a forty-ship convoy spread across eight nautical miles of ocean presents a target area that no screen of destroyers can fully cover. The escort commander must think in terms of probability, not certainty.
"The escort commander must think in terms of probability, not certainty. His task is not to eliminate the threat but to reduce the expected loss rate below the replacement rate. Anything above that threshold is attrition. Anything below it is victory."