Why a dud bomb could damage Libeccio yet leave a repairable ship

A bomb passed through Libeccio without detonating, rupturing fuel tanks and important piping. One suggested explanation, recalled with uncertainty, is that an armour-piercing bomb passed through the destroyer's light structure without enough resistance to set it off. A hole through a ship could be easier to isolate than damage from an explosion that warped bulkheads and door frames or opened seams. Being alongside also gave the crew access to shore support. The position of the later Fritz X detonations affected Roma and Warspite differently. Roma was lost after an internal explosion, while the weapon that passed through Warspite and detonated in the water caused severe but survivable damage.