All or Nothing (armor) - in Practice

In Practice

No navy built pure "all or nothing" battleships, although most navies put the theory into use to some degree. Designed and built within the full constraints of the Washington Treaty, the Royal Navy's Nelson class and the French navy's Dunkerque class came closest to the ideal.

The misgivings of building a pure "all or nothing" ship was that these had areas still vulnerable to guns of even modest warships, small arms fire, and blast damage from a ship's own guns. For instance, blast damage was to plague the careers of the Nelsons, a situation aggravated by the positioning of her guns. It was also considered demoralizing for crew, for example those serving in the secondary batteries, to know that they had no protection. The superstructure, for instance, housed crucial command stations, communications, and radar equipment. Other critical areas such as the rudder, propellers, and bow could not be armored, so damage to these areas could reduce a ship's maneuverability and buoyancy.

From the Nevada class on to its Iowa class, the United States Navy pioneered the all or nothing approach without taking it to its logical conclusion. For example, the US designed its battleships to give the crew additional protection instead of relying only on the armored deck of the citadel. These vessels had three armored decks: a sacrificial armored top deck to decap and set off bombs and shells; a splinter deck between the top; and citadel decks to protect the majority of the crew from shell and bomb fragments. In World War II-era battleships and modernized Standard type battleships, the secondary armament was also in armored turrets, the same type of mounts also found in newer fleet carriers and cruisers, since this was a vital defense against enemy aircraft (particularly Kamikazes).

Regardless of armoring scheme used, battleships still had crucial areas that could not be protected such as the bow, rudder, and propellers; good examples include Bismarck and Prince of Wales. The superstructure housing command facilities, communications, and radar also remained vulnerable; for instance Tirpitz suffered extensive topside damage in Operation Tungsten.