Editing Nelson-class battleship (section)

===Armour===
Armour weight was also reduced by using an internal, inclined armour belt sloped outward at 18 degrees from the vertical. The armour belt was {{convert|14|in|mm|abbr=on}} thick over the main magazines and control positions to {{convert|13|in|mm|abbr=on}} over the machinery and 6-inch gun magazines. The slope increased the relative thickness of the belt to a plunging projectile. Water-filled compartments, surrounded by air-filled ones, formed internal torpedo bulges which were fitted between the armour and the external hull of the ship, which was not armoured. The outer hull plating was meant to initiate detonation of shells which would then explode outside the armour. This innovation dispensed with external torpedo bulges which would otherwise have reduced the speed of the ships due to drag. Underwater protection for the ''Nelson''s was provided by a [[double bottom]] 5 feet (1.5 m) deep and a layered defence of an empty outer [[watertight compartment]] and an inner water-filled compartment. The torpedo defence system had a total depth of 12 feet (3.7 m) and was backed by a [[torpedo bulkhead]] 1.5 inches thick. The system was similar in design and effectiveness to that of ''[[HMS Hood|Hood]]'', and was rated to withstand an explosion of 750 lbs (340 kg) [[TNT]].<ref>{{Cite book|last=Raven|first=Alan|url=https://www.worldcat.org/oclc/2765218|title=British battleships of World War Two : the development and technical history of the Royal Navy's battleships and battlecruisers from 1911 to 1946|date=1976|publisher=Naval Institute Press|others=John, January 16- Roberts|isbn=0-87021-817-4|location=Annapolis|oclc=2765218}}</ref> The armour scheme was of the "[[All or nothing (armour)|all or nothing]]" principle; areas were either well protected, from the front of "A" barbette rearwards to the after 6-inch turrets, or were not protected at all, disposing of the multiple intermediate thickness of armour seen in older designs. For the first time a British battleship had a single, {{convert|6.25|in|mm|abbr=on}} thick armoured deck to protect against plunging shells and aircraft-launched bombs, with {{convert|3.75|in|mm|abbr=on}} armour over the machinery spaces and {{convert|4.25|in|mm|abbr=on}} armour on the lower deck over the stern, both on top of the 0.5 in (12.7&nbsp;mm) deck plating. The main turrets had {{convert|16|in|mm|abbr=on}} armour on the faces, {{convert|11|in|mm|abbr=on}} on the sides, {{convert|7.25|in|mm|abbr=on}} on the roof and {{convert|9|in|mm|abbr=on}} on the rear with {{convert|15|in|mm|abbr=on}} around the barbettes. The secondary turrets, however, had only {{convert|1|in|mm|abbr=on}} NC all round over 0.5 in (12.7&nbsp;mm) structural steel plates.<ref name="ReferenceA"/><ref name="referenceD"/>{{Page needed|date=March 2023}}