Why a bursting shell needs containment

Shell failure was a physical problem as well as a manufacturing one. A projectile that breaks up before its fuze functions disperses its explosive filling, while a burst on impact expends much of its energy outside the ship. A hit can still weaken armour or damage joints, but it is far less likely to produce the pressure and internal effects expected after penetration. German planning assumed that British shells were comparable to German ammunition, and post-Jutland intelligence recorded surprise at how ineffective the British projectiles had been. Lützow's eventual loss shows that defective projectiles were still dangerous, although far less dependable than the Royal Navy required. This mechanism explains why British accuracy did not translate into commensurate damage.