Editing Formidable-class battleship (section)

==Design==
[[File:Formidable class battleship diagrams Brasseys 1906.jpg|thumb|left|Right elevation and deck plan as depicted in ''Brassey's Naval Annual 1906'']]

Design work on what became the ''Formidable'' class began with a meeting of the [[Board of Admiralty]] on 3 May 1897, where the general parameters of the new class was discussed. The Board concluded that repeating the {{sclass|Canopus|battleship|4}} would not be a workable solution, since the [[Imperial Japanese Navy]] had begun building larger, {{convert|15000|t|adj=on}} battleships and the ''Canopus'' design was too small to carry the new [[Armstrong Whitworth 12 inch /40 naval gun|40-calibre {{convert|12|in|mm|adj=on|0}} Mk IX guns]], which were significantly heavier than the shorter [[BL 12-inch Mk VIII naval gun|35-calibre BL 12-inch Mk VIII guns]]. The design staff determined that it was possible to construct a new ship that incorporated the advances of the ''Canopus'' class—namely, [[Krupp armour]] and improved engines and [[water-tube boiler]]s—on a larger [[hull (watercraft)|hull]] like the earlier {{sclass|Majestic|battleship|1}}s without increasing displacement and keeping the same speed as the ''Canopus'' class.{{sfn|Burt|p=190}}

The [[Director of Naval Construction]], [[William Henry White]], provided two design options, both modified versions of the basic ''Majestic'' form. Both variants had a main battery of four 12-inch guns, [[belt armour]] that was {{convert|8|in|0}} thick, and a top speed of {{convert|18|kn|lk=in}}. The main difference between the designs was the number of secondary guns; the first had twelve {{convert|6|in|abbr=on|0}} guns and the second had fourteen of the guns. [[Displacement (ship)|Displacement]] differed by just 200&nbsp;tons, at {{convert|14700|t|abbr=on}} for the 12-gun variant and {{convert|14900|t|abbr=on}} for the other one. White preferred the 14-gun version, though the consensus of the Board was that twelve guns were sufficient, on the basis that the two additional guns would overcrowd the upper deck, where they would have been placed, and would have increased the size of the crew too much. Additionally, a secondary battery of twelve guns was deemed to be sufficient in comparison to most other foreign battleships. And while an increase in offensive power would have been welcome, members of the Board decided that the weight savings gained by omitting the two guns could be used to strengthen the ships' armour, which they preferred at a time where naval guns were becoming increasingly powerful.{{sfn|Burt|pp=190, 192}}

The board adopted the 12-gun version, along with a request to increase the belt to {{convert|9|in|0}}. The thicker armour increased displacement to {{cvt|15000|t|LT|lk=on}}. The board requested that White prepare drawings for this new design on 19 June. A model was created by 17 August, which allowed the design staff to refine the hull shape. The staff cut away the [[Deadwood (shipbuilding)|deadwood]] forward and aft, which made the vessels more handy.{{sfn|Burt|p=190}}

Due to their similarity, some like historian Tony Gibbons consider the five {{sclass|London|battleship|1}}s to be part of the ''Formidable'' class,{{sfn|Gibbons|p=151}} though most historians view them as a distinct class. The five ''London''-class ships differed from the ''Formidable''s in their protection layout, which abandoned the forward armoured [[bulkhead (partition)|bulkhead]] in favour of an armoured belt that extended all the way to the [[Stem (ship)|stem]].{{sfn|Lyon & Roberts|p=37}}{{sfn|Pears|p=30}}{{sfn|Willmott|p=15}}{{sfn|Burt|p=206}} Regardless, the ''Formidable'' design provided the basis for the five ''London''s that were ordered under the 1898 programme.{{sfn|Burt|p=206}} The only extant British built pre-dreadnought remaining, the Japanese battleship {{ship|Japanese battleship|Mikasa||2}} was also built to a slightly modified design, the chief difference being the addition of another pair of 6-inch guns.{{sfn|Preston|p=189}}

===General characteristics and machinery===
The ships of the ''Formidable'' class were {{convert|400|ft|0}} [[length between perpendiculars|long between perpendiculars]], {{convert|411|ft|abbr=on|0}} [[length at the waterline|long at the waterline]], and {{convert|431|ft|9|in|0}} [[length overall|long overall]]. They had a [[beam (nautical)|beam]] of {{convert|75|ft|abbr=on|0}} and a [[draft (hull)|draft]] of {{convert|26|ft|abbr=on|0}} normally and {{convert|28|ft|8|in|abbr=on|0}} fully loaded. The three ships displaced between {{convert|14480|to|14720|LT}} normally and up to {{convert|15805|to|15930|LT}} fully loaded. [[Freeboard (nautical)|Freeboard]] was {{convert|23|ft|abbr=on}} forward, {{convert|16|ft|9|in|abbr=on}} [[amidships]], and {{convert|18|ft|abbr=on}} aft.{{sfn|Lyon & Roberts|p=36}}{{sfn|Burt|p=191}}

They had two pole masts fitted with [[fighting top]]s; each top carried a [[searchlight]], and four additional searchlights were mounted on the forward and aft [[Bridge (nautical)|bridges]]. Their crew size varied over the course of their careers; ''Irresistible'' had a crew of 788&nbsp;officers and [[Naval rating|ratings]] in 1901, and in 1910, ''Formidable'' had a crew of 711. After having been withdrawn from active service in 1917, ''Implacable'' had a crew of just 361. The ships carried a number of small boats that varied over the course of their careers, including a variety of steam and sail [[Pinnace (ship's boat)|pinnaces]], sail [[Launch (boat)|launches]], [[Cutter (boat)|cutters]], [[galley]]s, [[whaler]]s, three [[Captain's gig|gigs]], [[dinghy|dinghies]], and [[raft]]s.{{sfn|Lyon & Roberts|p=36}}{{sfn|Burt|p=191}}

The ''Formidable''-class ships were powered by a pair of 3-cylinder [[triple-expansion engine]]s that drove two inward-turning [[propeller|screws]], with steam provided by twenty [[Belleville boiler]]s. The boilers were divided into three [[fire room|boiler rooms]] and were trunked into two [[funnel (ship)|funnels]] located amidships. The boilers proved to be troublesome in service, with all three members of the class experiencing problems with them, particularly as the ships aged, between 1909 and 1914. The ''Formidable''-class ships were rated for a top speed of {{convert|18|kn}} from {{convert|15000|ihp|lk=in}}. The ships' normally carried {{convert|900|t|abbr=on}} of coal for the boilers, but had a total capacity of {{convert|1920|to|2000|t|abbr=on}}, which provided a cruising range of {{convert|5100|nmi|abbr=on}} at a cruising speed of {{convert|10|kn}}.{{sfn|Lyon & Roberts|p=36}}{{sfn|Burt|pp=191, 196}}

===Armament and armour===
[[File:Formidable class 12 inch gun turret right elevation.jpg|thumb|upright|left|Right elevation of 12 inch gun turret & ammunition hoists]]

''Formidable'' and her sisters had four {{convert|12|in|mm|adj=on|0}} 40-calibre Mk IX guns mounted in twin-[[gun turret]]s fore and aft; these guns were mounted in circular barbettes that allowed all-around loading or elevation. Shell allowance was 80&nbsp;rounds per gun. The ''Formidable'' class were the first to carry these guns, which featured several improvements over the earlier Mk VIII guns used in older battleships, including a stronger barrel design and higher [[muzzle velocity]]. ''Formidable'' and ''Implacable'' had BVI type mountings for their guns, while ''Irresistible'' received newer BVII mounts, the primary difference between the two types being the arrangement of the shell hoists and other equipment.{{sfn|Burt|pp=190–192}} Both types of mountings had a range of elevation from -5&nbsp;degrees to of 13.5&nbsp;degrees. The BVI mounts required the guns to return to 4.5&nbsp;degrees to be loaded, while the BVII mounts allowed for loading at any angle. The guns had a muzzle velocity of {{convert|2562|to|2573|ft/s}}, and they were capable of penetrating 12 inches of Krupp armour at a range of {{convert|4800|yd}}. At their maximum elevation, the guns had a range of {{convert|15300|yd}}.{{sfn|Friedman|pp=57–58}} The guns had a [[rate of fire]] of one shot every eighty seconds.{{sfn|Fraser|p=44}}

The ships also mounted a [[secondary armament|secondary battery]] of twelve [[BL 6 inch Mk VII naval gun|{{convert|6|in|mm|adj=on|0}} 45-calibre guns]] mounted in [[casemate]]s, which were supplied with 200&nbsp;rounds per gun. The guns had a muzzle velocity of {{convert|2536|ft/s|abbr=on}}. These guns could penetrate 6&nbsp;inches of Krupp armour at {{convert|2500|yd}}. Maximum elevation was 14&nbsp;degrees, which allowed the guns to engage targets out to {{convert|12000|yd}}.{{sfn|Friedman|pp=79–81}} For close-range defence against [[torpedo boat]]s, they carried ten [[QF 12 pounder 12 cwt naval gun|12-pounder guns]] with 300&nbsp;rounds per gun and six [[QF 3 pounder Hotchkiss|3-pounder guns]] with 500&nbsp;shells per gun. As was customary for battleships of the period, they were also equipped with four [[British 18 inch torpedo|{{convert|18|in|0|adj=on}} torpedo]] tubes submerged in the hull.{{sfn|Lyon & Roberts|p=36}}{{sfn|Burt|p=191}}

The ''Formidable''-class ships made more extensive use of Krupp steel than the preceding ''Canopus'' class, with most of their side armour consisting of the stronger steel. They had an armoured belt that was {{convert|9|in|0}} thick and extended from the forward main battery barbette to the aft barbette; the transverse bulkheads on either end of the belt were 9&nbsp;in thick forward and {{convert|9|to|10|in|abbr=on|0}} thick aft. The belt extended from main deck level ({{convert|9|ft|6|in|0|abbr=on}} above the [[waterline]]) to {{convert|5|ft|6|in|abbr=on|0}} below the waterline. The ships' side plating forward of the belt was {{convert|3|in|abbr=on|0}} thick, while it was only {{convert|1.5|in|abbr=on|0}} aft of the belt. The ships were fitted with two armoured decks; the first was a flat deck that was {{convert|1|in|abbr=on|0}} thick, above the main deck, which was 2&nbsp;in on the flat portion and increased slightly to 3&nbsp;in on the sloped sides, where it connected to the belt armour.{{sfn|Lyon & Roberts|p=36}}{{sfn|Burt|p=191, 193–195}}

The ships' main battery turrets sides and faces were {{convert|8|in|0|abbr=on}} thick—reduced slightly compared to earlier ships to account for the heavier belt armour—with {{convert|10|in|abbr=on|0}} thick rears. The turret roofs were 3&nbsp;in thick. The turrets sat atop 12&nbsp;in thick [[barbette]]s, though ''Irresistible''{{'}}s barbette armour was reduced in thickness to 10&nbsp;in behind the belt. Above the main belt was a [[strake]] of armour that protected the casemate guns, which was 6&nbsp;inches thick; behind the casemates, an interior bulkhead that was {{convert|2|in|abbr=on}} thick protected the interior of the ship. Their forward [[conning tower]] had {{convert|10|to|14|in|0|abbr=on}} thick sides, with a communication tube below the tower that had armour protection that was {{convert|8|in|abbr=on|0}} thick. The aft conning tower had 3&nbsp;in thick sides with a 3&nbsp;in tube below.{{sfn|Lyon & Roberts|p=36}}{{sfn|Burt|p=191, 194–195}}