Torpedo nets could protect an anchored or slow-moving ship by detonating a weapon away from the hull. Underway, however, they reduced speed, trailed toward the surface above a torpedo's running depth, and imposed heavy handling work on the crew. Larger explosive charges made existing internal magazine protection increasingly inadequate. Experiments beginning in 1913 used the old battleship Hood to test full-scale structural changes, gradually producing permanent side protection that remained effective while the ship moved: the torpedo bulge. D'Eyncourt says that no ship fitted with the resulting arrangement was sunk by torpedo during the First World War, even though several were struck more than once.
Chapter · 15:51-18:15
From torpedo nets to structural bulges
Full-scale experiments on the old battleship Hood helped replace cumbersome torpedo nets with structural side protection that remained useful while a ship was underway.