A diving expedition during the summer of 2003 provided corroboration of this practice. It examined the wrecks of "Invincible", "Queen Mary", "Defence", and "Lützow" to investigate the cause of the British ships' tendency to suffer from internal explosions. From this evidence, a major part of the blame may be laid on lax handling of the cordite propellant for the shells of the main guns. The wreck of the "Queen Mary" revealed cordite containers stacked in the working chamber of the X turret instead of the magazine.