View source for Lyon-class battleship

{{short description|Proposed fleet of battleships for the French Navy}}
{|{{Infobox ship begin}}
{{Infobox ship image
|Ship image=Lyon class linedrawing.png
|Ship caption=Plan and left elevation drawing of the ''Lyon'' class as depicted in the ''Journal of United States Artillery''
}}
{{Infobox ship class overview
|Name=Lyon
|Builders=France
|Operators={{navy|France}}
|Class before={{sclass|Normandie|battleship|4}}
|Class after={{sclass|Dunkerque|battleship|4}}
|Cost=
|Total ships planned=4
|Total ships completed=0
|Total ships cancelled=4
}}
{{Infobox ship characteristics
|Hide header=
|Header caption=
|Ship type=[[Battleship]]
|Ship displacement={{cvt|29600|t|LT|0|lk=on}}
|Ship length=*{{cvt|190|m|ftin}} ([[Length between perpendiculars|p/p]])
* {{cvt|194.5|m|ftin}} ([[o/a]])
|Ship beam={{convert|29|m|ftin|abbr=on}}
|Ship draft={{convert|8.65|to|9.2|m|ftin|abbr=on}}
|Ship propulsion=*4 shafts
* Mixed [[steam turbine]]s and [[triple-expansion steam engine]]s or all-turbine systems
|Ship speed={{convert|21|kn|lk=in}}
|Ship power={{convert|40000|CV|shp|abbr=on|lk=on}}
|Ship crew=
|Ship armament=*4 × quadruple [[340mm/45 Modèle 1912 gun|{{cvt|34|cm|1}} guns]]
* 24 × single {{convert|138.6|mm|abbr=on|1}} guns
* 2 × single {{convert|47|mm|abbr=on}} [[AA gun]]s
* 6 × [[torpedo tube]]s (submerged)
|Ship armor=*[[Belt armor|Waterline belt]]: {{cvt|300|mm|in|1}}
* [[Deck (ship)|Deck]]: {{cvt|42|or|70|mm|in|1}}
* [[Gun turret]]s: {{cvt|300|mm|in|1}}
|Ship notes=
}}
|}

The '''''Lyon'' class''' was a set of [[battleship]]s planned for the [[French Navy]] ({{lang|fr|Marine Nationale}}) in 1913, with construction scheduled to begin in 1915. The class was to have comprised four ships, named ''Lyon'', ''Lille'', ''Duquesne'', and ''Tourville''. The first two were named for cities in France, and the latter pair honored the French admirals [[Abraham Duquesne]] and [[Anne Hilarion de Tourville]]. The ''Lyon'' class' design was an improvement on the previous {{sclass|Normandie|battleship|4}}, utilizing a fourth quadruple-[[gun turret]] to mount a total of sixteen {{convert|34|cm|abbr=on|1}} guns. Construction on the ''Lyon''s was cancelled due to the August 1914 outbreak of [[World War I]], before any of the ships were [[laid down]].

==Design==
[[File:Normandie-class illustration.jpg|thumb|left|An artist's depiction of the {{sclass|Normandie|battleship|4}}, which provided the basis for the ''Lyon'' design]]
The French Navy began a [[dreadnought battleship]] construction program in 1910 with the four ships of the {{sclass|Courbet|battleship|4}}. Two years later, the French legislature passed a naval law which called for a fleet of twenty-eight battleships by 1920. Under this plan, three ships would be ordered in 1912; these became the {{sclass|Bretagne|battleship|4}}. Two more were projected for 1913 and another two for 1914, which were to be the first four {{sclass|Normandie|battleship|1}}s, though an amendment to the law increased the pace of construction to four ''Normandie''s in 1913 and a fifth of the same design in 1914. Four ships were projected for 1915.<ref>Gardiner & Gray, pp. 190–191</ref><ref>Jordan & Caresse, p. 162</ref> Design work on the vessels to follow the ''Normandie''s began in 1912; the design staff submitted several proposals for the new battleships, with [[displacement (ship)|displacements]] ranging from {{convert|27000|MT|LT|sp=us|0|lk=on}} to {{convert|29000|MT|LT|abbr=on|0}}.<ref name=GG199/> In 1913, the Navy authorized a fourth class of battleships, what was to have been the ''Lyon'' class, and scheduled their construction for 1915.<ref name=O47>O'Brien, p. 47</ref><ref>Wilmott, p. 143</ref>

One of the main considerations for the new design was the armament to be carried. The French were aware that the latest British battleships—the {{sclass|Queen Elizabeth|battleship|4}}—were to be armed with {{cvt|38|cm}} guns, prompting significant consideration of matching this [[caliber]] for the ''Lyon'' design. The design staff prepared four variants, two armed with the standard French 34&nbsp;cm gun in twin or quadruple [[gun turret]]s, and two armed with 38&nbsp;cm guns in twin turrets. The designers also briefly considered a ship armed with twenty {{cvt|30.5|cm|0}} guns in quadruple turrets, but the decrease in gun caliber was deemed to be a step in the wrong direction and it was quickly rejected. At the time, the French Navy believed that at the expected battle ranges in the Mediterranean, the 34&nbsp;cm gun was effective and so the larger 38&nbsp;cm gun was not necessary.<ref name=JC204>Jordan & Caresse, p. 204</ref> The design staff determined the 38&nbsp;cm gun would take too long to design, so the proposals that incorporated these weapons were rejected and officials chose between the two 34 cm proposals. The first proposal, which mounted fourteen guns, was a {{convert|27500|MT|LT|adj=on|0|sp=us}} ship {{convert|185|m|sp=us}} long. On 24 November 1913, the design staff instead chose the slightly larger second design, armed with sixteen guns in four quadruple turrets, but the specific 34&nbsp;cm gun to be used to arm the ships was still an open question.<ref name=O47/>

The first proposal by the Directorate of Artillery ({{lang|fr|Direction de l'artillerie}}) was for the existing 45-[[caliber (artillery)|caliber]]{{efn|In this case, "caliber" refers to the length of the gun expressed in terms of the barrel diameter; a 45-caliber gun would be 45 times long as it is in diameter.}} gun used by the ''Bretagne'' and ''Normandie''-class ships to be modified to use a slightly longer shell that weighed {{cvt|590|kg}}, {{cvt|50|kg}} more than the existing shell, and was optimized for underwater performance. The second proposal was for a 50-caliber gun that fired a larger {{cvt|630|kg|adj=on}} shell. Accommodating the extra volume and weight of the longer gun was estimated to increase the displacement of the design to {{cvt|31000|-|32000|t|LT|abbr=on}} and to increase the cost from 87 million [[French franc|francs]] to 93–96 million. The first option was ultimately selected in February 1914.<ref name=jc6>Jordan & Caresse, p. 206</ref> The first two ships, ''Lyon'' and ''Lille'', were scheduled to be ordered on 1 January 1915, and ''Duquesne'' and ''Tourville'' would have followed on 1 April.<ref name=GG199/>

The run-up to and beginning of World War I led to the end of the ''Lyon'' class. The French government [[mobilization|mobilized]] its reserve forces in July, a month before the conflict, and thereby stripped its shipyards of many of the specialized tradesmen required for constructing the ships. The French also redirected their industrial capacity to weapons and munition orders from the army. In light of such constraints, the navy decided that only those ships that could be completed quickly would be worked upon, such as the ''Bretagne''s.<ref name=O47/><ref>Jordan & Caresse, p. 189</ref>

===Ships===
{|class="wikitable plainrowheaders"
|+ Construction data
!scope="col"|Ship
!scope="col"|Builder<ref name=GG199>Gardiner & Gray, p. 199</ref>
|-
|scope="row"|''Lyon''
|[[Ateliers et Chantiers de la Loire]], [[St Nazaire]]
|-
|scope="row"|''Duquesne''
|[[Arsenal de Brest]], [[Brest, France|Brest]]
|-
|scope="row"|''Lille''
|[[Société Nouvelle des Forges et Chantiers de la Méditerranée|Forges et Chantiers de la Méditerranée]], [[La Seyne]]
|-
|scope="row"|''Tourville''
|[[Arsenal de Lorient]], [[Lorient]]
|-
|}

===Characteristics===
The ships would have been {{convert|190|m|ftin|abbr=on}} [[length between perpendiculars|long between perpendiculars]] and {{convert|194.5|m|ftin|abbr=on}} [[length overall|long overall]]. They would have had a [[beam (nautical)|beam]] of {{convert|29|m|ftin|abbr=on}} and a [[draft (hull)|draft]] of {{convert|8.65|to|9.2|m|ftin|abbr=on}}.<ref name=GG199/> Their displacement was estimated at {{convert|29600|MT|LT}}. The propulsion system had not been settled by the time the class was cancelled; the design staff proposed either the mixed [[steam turbine]] and [[triple-expansion engine]] system used in the first four ships of the preceding ''Normandie'' class or the all-turbine system used in the last ''Normandie''-class ship, {{ship|French aircraft carrier|Béarn||2}}, in a memo dated 13 September 1913. They also considered new geared turbines that had proved satisfactory in the new [[destroyer]] {{ship|French destroyer|Enseigne Gabolde||2}}. The final design called for a propulsion system rated at {{convert|40000|CV|shp|lk=on}} with a top speed of {{convert|21|kn|lk=in}}. An unknown number of boilers were to be trunked into two [[funnel (ship)|funnels]] [[amidships]].<ref>Jordan & Caresse, pp. 204–205</ref>

The [[main battery]] of the ''Lyon''s would have been sixteen [[340mm/45 Modèle 1912 gun|34&nbsp;cm Modèle 1912M guns]] mounted in four quadruple-gun turrets. They would have all been mounted on the centerline, although the arrangement is not clear.<ref name=jc6/> A preliminary sketch, attached to the design staff's memo of 19 September 1913, showed one turret was placed forward, one amidships, and two in a [[superfire|superfiring pair]] aft, although the contemporary ''Journal of United States Artillery'' suggests the turrets would have been mounted in two superfiring pairs, forward and aft.<ref name=jc6/><ref>Barnett, p. 377</ref> The turrets weighed {{convert|1500|MT|LT|abbr=on}}, and were electrically trained and hydraulically elevated. The guns were divided into pairs and mounted in twin cradles; a {{convert|40|mm|abbr=on}} thick bulkhead divided the turrets. Each pair of guns had its own ammunition hoist and [[magazine (artillery)|magazine]]. They could be fired simultaneously or independently.<ref>Friedman, p. 209</ref> Before work on the ''Lyon'' class had started, the French Navy had begun experimenting with new types of shells. After learning that shells had penetrated the hulls of battleships underwater to burst below their armored belts during the [[Battle of the Yellow Sea]] in 1904 and during British gunnery trials in 1907, the French Navy began investigating how they might optimize shell design to improve their performance through the water. By 1913 the navy believed that it had a design that could be accurate through the water for a distance of {{convert|100|m|sp=us|0}}.<ref>Friedman, pp. 204, 208</ref>

The [[secondary armament]] was to consist of twenty-four guns, either the 55-caliber [[Canon de 138 mm Modèle 1910 Naval gun|138.6&nbsp;mm Modèle 1910]] or a new automatic model, each singly-mounted in [[Casemate#Single casemates (1889 onwards)|casemates]] in the hull sides.<ref name=GG199/> The M1910 guns fired a {{convert|36.5|kg|abbr=on}} shell at a muzzle velocity of {{convert|830|m/s|abbr=on}}.<ref>Friedman, p. 225</ref> The ships would also have been equipped with a pair of {{convert|47|mm|abbr=on}} [[anti-aircraft gun]]s and six submerged [[torpedo tube]]s of unknown size.<ref name=JC204/>

The ships would have been protected with a modified version of the armor layout of the earlier ''Normandie'' class. The primary alteration was that the upper [[strake]] of armor intended to protect the secondary armament was reduced from {{convert|160|mm|in|sp=us|1}} on the ''Normandie''s to {{convert|100|mm|in|sp=us|1}}. The reduction compensated for the additional armor below the waterline to better protect the hull against "diving" shells. The [[waterline]] [[belt armor|armor belt]] would have been {{convert|300|mm|in|1|sp=us}} thick between the [[barbette]]s of the end turrets. The turrets were also intended to be protected with an armor thickness of 300&nbsp;millimeters on their faces. The lower armored [[deck (ship)|deck]] would have consisted of a total of {{convert|42|mm|1|sp=us}} of [[mild steel]]; the deck sloped downwards to meet the bottom of the waterline belt and the sloped portion of the deck would have had a total thickness of {{convert|70|mm|sp=us}}. The upper armored deck was intended to be {{convert|40|mm|in|sp=us}}. Between the end barbettes, below the waterline belt, the thickness of the hull would have graduated from {{convert|80|to|35|mm|sp=us}} in thickness down to a depth of {{convert|6|m|ftin|sp=us}} below the waterline forward and {{convert|4.5|m|ftin|sp=us}} aft.<ref>Jordan & Caresse, pp. 204–207</ref>

== Notes ==

===Footnotes===
{{notelist}}

===Citations===

{{reflist|20em}}

==References==
* {{cite journal |last1=Barnett |first1=M. K. |date=1915 |title=The New French Battleship "Tourville" |url=https://babel.hathitrust.org/cgi/pt?id=mdp.39015025964134;view=1up;seq=445 |journal=Journal of the United States Artillery |volume=44 |issue=2 |oclc=225526618 |pages=377–379 |publisher=School Board of the Coast Artillery School |doi= 10.1038/scientificamerican10101915-45|access-date=4 November 2018 |bibcode=1915SciAm.113...45B |url-access=subscription }}
* {{cite book|last=Friedman|first=Norman|title=Naval Weapons of World War One: Guns, Torpedoes, Mines and ASW Weapons of All Nations; An Illustrated Directory|publisher= Seaforth Publishing|location=Barnsley|year=2011|isbn=978-1-84832-100-7 |authorlink=Norman Friedman}}
* {{cite book |editor1-last=Gardiner|editor1-first=Robert|editor2-last=Gray|editor2-first= Randal|title=Conway's All the World's Fighting Ships 1906–1921|year=1985 |location=Annapolis |publisher=Naval Institute Press|isbn=978-0-87021-907-8|name-list-style=amp | url=https://archive.org/details/allworldsfightin00rgre}}
* {{cite book |last1=Jordan |first1=John |last2=Caresse |first2=Philippe |title=French Battleships of World War One |date=2017 |publisher=Naval Institute Press|location=Annapolis|isbn=978-1-59114-639-1 |name-list-style=amp}}
* {{cite book |last=O'Brien|first=Phillips Payson|title=Technology and Naval Combat in the Twentieth Century and Beyond|year=2001|location=London|publisher=Frank Cass|isbn=978-0714651255}}
* {{Cite book|editor-last=Willmott|editor-first=H. P.|title=The Last Century of Sea Power (Volume 1, From Port Arthur to Chanak, 1894–1922)|year=2009|location=Bloomington|publisher=Indiana University Press|isbn=978-0-2533-5214-9}}

{{Lyon class battleship}}
{{French battleships}}
{{WWI French ships}}

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[[Category:Battleship classes]]
[[Category:Proposed ships]]
[[Category:Battleships of the French Navy]]
[[Category:Ship classes of the French Navy]]