Editing Courageous-class aircraft carrier (section)

=== Protection ===
Little armour other than that of the [[barbette]]s was removed during their conversion to aircraft carriers. The transverse bulkheads were carried through the locations of the former barbettes. The flight deck was {{convert|0.625|in|mm}} in thickness.<ref>Burt 2012, pp. 273, 282</ref>

Unlike other British battlecruisers, the bulk of the armour of the ''Courageous''-class ships was made from [[Ultimate tensile strength|high-tensile]] steel (HTS), a type of steel used structurally in other ships. Their waterline [[Belt armor|belt]] consisted of {{convert|2|in|0}} of HTS covered by a {{convert|1|in|0|adj=on}} thick mild steel skin. It protected roughly the middle two-thirds of the ship with a one-inch extension forward to the two-inch forward transverse [[bulkhead (partition)|bulkhead]] well short of the bow. The belt had a height of {{convert|23|ft|m|0}}, of which {{convert|18|in|m|1}} was below the designed waterline. From the former forward barbette, a 3-inch bulkhead extended out to the ship's side between the upper and lower decks and a comparable bulkhead was in place at the former location of the rear barbette as well. Four decks were armoured with thicknesses varying from {{convert|0.75|–|3|in}}, thickest over the magazines and the steering gear. After the [[Battle of Jutland]], {{convert|110|LT|t}} of extra protection was added to the deck around the magazines.<ref>Burt 1986, pp. 308, 313</ref>

The [[torpedo bulkhead]]s were increased during building from 0.75–{{convert|1.5|in|abbr=on}} in thickness.<ref>Roberts, pp. 54, 106, 113</ref> All three ships were fitted with a shallow [[anti-torpedo bulge]] integral to the hull, which was intended to detonate the torpedo before it hit the hull proper and deflect the underwater explosion to the surface, away from the ship. Later testing proved that it was not deep enough to accomplish its task and that it lacked the layers of empty and full compartments that were necessary to absorb the force of the explosion.<ref>Roberts, p. 111</ref>