Tonnerre-class ironclad

On 10 November 1871, the Minister of the Navy ({{lang|fr|Ministère de la Marine}}) Louis Pierre Alexis Pothuau issued a specification for a new coastal defense ship. Of the three alternatives submitted on 9 August 1872, the French Navy accepted that developed by Louis de Bussy, which was signed on 29 July. The design was based on his existing second-class coastal defense ships, as epitomised by the {{sclass|Bélier|ram|2}}, but with an armored deck raised by {{cvt|10|cm}}, sitting {{cvt|90|cm}} above the waterline and all vertical dimensions increased by 25 percent. Having a superficial similarity to the Royal Navy monitor {{HMS|Glatton|1871|2}} but with a shorter breastwork, the design was agreed and built as class of two vessels.{{sfn|Roberts|2021|page=80}}

File:Tonnerre (1875).jpg

Breastwork monitors that had hull of steel, the ships of the Tonnerre class had a single turret forward and a narrow superstructure, {{convert|6|ft|m|order=flip|abbr=on}} wide, aft.{{sfn|Campbell|1979|page=299}} The vessels displaced {{convert|5588|MT|LT|lk=on}}, had an overall length of {{convert|78.6|m|ftin|abbr=on}}, {{convert|75.6|m|ftin|abbr=on}} at the waterline and {{convert|73.6|m|ftin|abbr=on}} between perpendiculars. The ships' beam was {{convert|17.6|m|ftin|abbr=on}} at the waterline and draught was {{convert|6.421|m|ftin|abbr=on}} mean and {{convert|6.639|m|ftin|abbr=on}} aft. The ships' complement numbered 190 sailors of all ranks.{{sfn|Roberts|2021|page=80}}{{sfn|Brassey|1897|page=292}}

The powerplant for the two ships differed. Power for Tonnerre was provided by a single horizontal simple expansion steam engine while Fulminant was powered by a single horizontal Schneider compound engine. All drove one propeller shaft and vented through a single funnel, Tonnerre being distinguished by having a larger funnel. The engine on Tonnerre was rated at {{convert|3400|ihp|lk=on}} while that on Fulminant was rated at {{convert|3500|ihp}}. Steam was provided by eight boilers. The ships had a light mast and no sails.{{sfn|Roberts|2021|page=80}} In service, the ships were rated at {{convert|14|kn|0|lk=in}}.{{sfn|King|1881|page=21}}

The ships mounted a main battery of two {{cvt|274.4|mm|1}} 19.75-caliber Modèle 1875 guns in a single enclosed turret mounted forward. The guns were capable of firing every seven or eight minutes.{{sfn|Roberts|2021|page=80}} They each weighed {{cvt|27,850|kg}} and fired a shell that weighed {{cvt|216|kg}}.{{sfn|Roberts|2021|page=472}} They were hydraulically loaded using the Rendell system, which also powered the turret.{{sfn|King|1881|page=22}} This was the first use of hydraulics in the French Navy to power a turret and, despite the equipment being supplied by the British firm W. G. Armstrong & Company, ahead of the Royal Navy adopting it to use in its turrets.{{cite news|title=The French Navy|newspaper=The Engineer|date=22 February 1878|page=133|url=https://books.google.com/books?id=8lFHAQAAMAAJ}} Defence from torpedo boats was provided by either four {{convert|121|mm|abbr=on|adj=on}} 17-caliber 12-pounder bronze guns or four {{convert|100|mm|abbr=on|adj=on}} guns mounted at the corners of the flying deck, raised above the hull. The ships were fitted with a {{cvt|3|m}} ram.{{sfn|Roberts|2021|page=80}}{{sfn|Paloczi-Horvath|1996|page=110}}

The ships were fitted with wrought iron armor with a full-length waterline armor belt that tapered from a maximum thickness of {{cvt|330|mm|in|0}} amidships to {{cvt|250|mm|in|0}} forward and {{cvt|300|mm|in|0}} aft. The deck armor was {{cvt|50|mm|in|0}} thick amidships with ends had {{cvt|120|mm|in|0}} of wood mounted on {{cvt|10|mm|in|0}} plating. The belt stretched from {{cvt|1.51|m|in|0}} below the waterline to {{cvt|0.89|m|in|0}} above. The breastwork had armor that was {{cvt|333|mm|in|0}} amidships and 300 mm at the ends. The turret was also protected by armor that is 300 mm thick, although the gun ports themselves were {{cvt|350|mm|in|0}} thick.{{sfn|Roberts|2021|page=80}} The turret was itself {{convert|34|ft|6|in|m|order=flip|abbr=on}} in diameter. A cylindrical conning tower was mounted on the turret, supported on a fixed {{convert|4|ft|8|in|m|order=flip|abbr=on}} shaft.{{sfn|Campbell|1979|page=299}}

During their lives, the ships had their armament modified. Six {{convert|37|mm|adj=on}} Hotchkiss revolving cannon were added early in the vessels' service, which were replaced, in 1900, by six QF 3 pounder Hotchkiss and two {{convert|37|mm|adj=on}} Hotchkiss revolving cannons. Four {{cvt|60|cm}} Mangin searchlights were also added.{{sfn|Roberts|2021|page=80}}

Tonnerre and Fulminant were fully commissioned after undertaking trials on 1 April 1878 and 29 May 1885 respectively. Tonnerre was placed in reserve but was allocated to the Evolution Squadron ({{lang|fr|Escadre d'Evolutions}}) in 1884. Both vessels joined the Armored Division ({{lang|fr|Division cuirassé}}) of the Northern Squadron ({{lang|fr| Esadre du Nord}}) in 1891.{{sfn|Roberts|2021|page=81}} Although they saw little active service, the vessels participated in naval exercises. Fulminant joined the coastal defense ship {{ship|French ironclad|Tempête||2}}, three cruisers and nine torpedo boats in a training exercise over 22 days from 22 June.{{sfn|Thursfield|1892|page=62}} Tonnerre operated with fellow ironclads {{ship|French ironclad|Furieux||2}} and {{ship|French ironclad|Victorieuse||2}} on another exercise between 26 July and 4 August 1893. Although nominally defending Cherbourg, the ship made a successful attack against a more powerful force on 3 August using dummy torpedoes.{{cite news|title=The French Naval Manoeuvres|newspaper=The Times|date=24 August 1893|issue=34038|page=4}} On 7 September 1894, it was announced that they were to be retired from active service and replaced by the newer {{sclass|Jemmapes|ironclad}}s.{{cite news|title=Naval & Military Intelligence|newspaper=The Times|date=8 September 1894|issue=34364|page=10}}

French naval doctrine was changing and the focus on coastal defense was being replaced by one of larger sea-going warships. The size of ships was also increasing, and newer, more capable battleships entered service.{{sfn|Paloczi-Horvath|1996|page=50}} Other technologies were also advancing that made the ships vulnerable to new forms of attack. In July 1902, Fulminant took part in a trial for the {{sclass|Aigrette|submarine}}s, where the ship acted as the target for them to demonstrate their stealthy characteristics.{{sfn|Partridge|Lambert|2024|page=145}} Neither vessel lasted far beyond that point. Tonnerre and Fulminant were struck on 12 December 1905 and 14 August 1908 respectively. Both were allocated to be target ships before being sold to be broken up, the latter on 4 November 1912 and the former between 1920 and 1922.{{sfn|Roberts|2021|page=81}}

{{reflist|20em}}

• {{cite book | editor-last=Brassey | editor-first=Thomas | chapter=Part II: British and Foreign Armoured and Unarmoured Ships | title=The Naval Annual 1897 | year=1897 | location=Portsmouth | publisher=J. Griffin & Co. | pages=227–335 | oclc=1342523853 | editor-link=Thomas Brassey, 1st Earl Brassey}}
• {{cite book | last=Campbell | first=N. J. M. | chapter=France | title=Conway's All the World's Fighting Ships 1860–1905 | editor1-last=Chesneau | editor1-first=Roger | editor2-last=Kolesnik | editor2-first=Eugene M. | publisher=Conway Maritime Press | location=Greenwich, UK | year=1979 | isbn= 978-0-85177-133-5 | name-list-style=amp | url-access=registration | url=https://archive.org/details/conwaysallworlds0000unse_l2e2 | pages=282–333}}
• {{cite book | last=King | first=J. W. | title=The War-ships and Navies of the World | location=Boston | publisher=A. Williams and Company | year=1881 | url=https://books.google.com/books?id=9v8_AAAAYAAJ}}
• {{cite book | last=Paloczi-Horvath | first=George | title=From Monitor to Missile Boat: Coast Defence Ships and Coastal Defence Since 1860 | publisher=Naval Institute Press | location=Annapolis, Maryland | year=1996 | isbn=978-1-55750-270-4}}
• {{cite book | last1=Partridge | first1= Colin | last2=Lambert | first2=Andrew | title=The Channel Islands in Anglo-French Relations, 1689-1918 | publisher=Boydell Press | location=Woodbridge, Suffolk | year=2024 | isbn=978-1-78327-655-4}}
• {{cite book | last=Roberts | first=Stephen | title=French Warships in the Age of Steam 1859–1914 | year=2021 | location=Barnsley | publisher=Seaforth Publishing | isbn=978-1-5267-4533-0}}
• {{cite book | editor-last=Thursfield | editor-first=Thomas | chapter=Chapter III: British and Foreign Armoured and Unarmoured Ships | title=The Naval Annual 1892 | year=1892 | location=Portsmouth | publisher=J. Griffin & Co. | pages=61–88}}

{{Tonnerre-class ironclad}}

{{French ironclads}}

{{DEFAULTSORT:Tonnerre class ironclad}}

Category:Coastal defense ship classes

Category:Ship classes of the French Navy

Category:Ships built in France

Tonnerre-class ironclads