The mine planted by U-73 remained effective a month after the submarine left the Kea Channel, illustrating the delayed power of mine warfare. Britannic had improved watertight protection after Titanic, but the blast damaged several compartments, a boiler tunnel carried flooding aft, and a watertight door failed. As the ship listed, open portholes used to ventilate hospital wards admitted water above the intact bulkheads. Those independent failures accumulated until a condition the design could survive became uncontrollable flooding.
Chapter · 10:21-19:02
Britannic, U-73, and the delayed power of submarine mines
Britannic's loss shows how a mine laid a month earlier defeated improved subdivision through cumulative flooding and open ward portholes.