The Swordfish's fabric covering could make some heavy anti-aircraft rounds less effective because shells might pass through without meeting enough resistance to detonate. Machine-gun fire and Italian 20 mm weapons posed a greater threat to the engine, crew, and the aircraft's few substantial structures. This did not make the aircraft invulnerable: a direct hit on the engine or crew could still be fatal, and the harbour was filled with intense fire. From his higher flare-dropping position, Charles Lamb thought the barrage below looked unsurvivable even though much of it passed above the torpedo aircraft.
Notable Point · 29:26-32:32
Why heavy flak could pass through Swordfish fabric
Canvas covering gave some heavy anti-aircraft shells too little resistance to detonate, although light fire and direct hits to the engine or crew remained dangerous.