The misgivings of building a pure "all or nothing" ship were that they had areas still vulnerable to guns of even modest warships, small arms fire, blast damage from a ship's own guns, bombs, strafing, and torpedoes. For instance, blast damage was to plague the careers of the "Nelson" class ships, a situation aggravated by the positioning of their guns. The superstructure, for instance, housed crucial command stations, communications, and radar equipment. Regardless of armoring scheme used, many critical areas such as the rudder, propellers, and bow could not be protected, so damage to these areas could reduce a ship's maneuverability and buoyancy. For instance, "Bismarck" and "Hiei" were lost due to rudder damage; the relatively large and "soft" unarmored bow structures of Japanese superbattleships "Yamato" and "Musashi" proved to be their Achilles' heel as flooding there rendered them unstable and unmaneuverable long before they were actually in danger of sinking. The superstructure housing command facilities, communications, and radar also remained vulnerable; for example, "Hiei" was rendered ineffective by a saturation bombardment of small projectiles which set her superstructure afire, "Tirpitz" suffered extensive topside damage in Operation Tungsten, and USS "South Dakota" was forced to withdraw from a night battle when relatively superficial damage to her superstructure knocked out her radars and disrupted her already-compromised electrical systems, killed 58 and wounded 60 crew members, and she fell out of the battle. The secondary batteries (including dual-purpose guns and heavy anti-aircraft guns) had less protection being outside the main armor citadel, and the light anti-aircraft gun were on exposed mounts with little or no armor (especially the extra AA guns added in the 1944 refit of the ), so dive bombing and fighter strafing attacks on "Tirpitz" (Operation Tungsten) and "Yamato" (Operation Ten-Go) caused heavy casualties among anti-aircraft gunners.