French battleship Iéna Iéna was a pre - dreadnought battleship of the French Navy . The ship ' s keel was laid in 1898 and she was completed four years later . Her design was derived from the preceding s with a heavier secondary battery and thicker armour . She retained the tumblehome characteristic of all large French warships of this period that caused stability issues . Upon completion " Iena " was assigned to the Mediterranean Squadron and remained there for the duration of her career . She participated in the annual fleet manoeuvers and made many visits to French ports in the Mediterranean . While docked for repairs , " Iéna " was gutted on 12 March 1907 by a magazine explosion caused by the decomposition of well - aged " Powder B " propellant . While it was possible to repair her , the ship was not thought worth the time or expense . Her hulk was used as a gunnery target before it was sold for scrap in 1912 . Design . " Iéna " was designed at the request of the Board of Construction ( ) to follow the " Charlemagne " class ships whose seakeeping qualities were not entirely satisfactory . But Constructor Thibaudier just modified the " Charlemagne " s design with a heavier secondary battery and thicker armour , distributed in a slightly different manner . This increased her displacement by in comparison to the older ships and she retained the pronounced tumblehome that was the cause of the stability problems . General characteristics . The " Iéna " was longer than her predecessors , at overall . She had a beam of and , at deep load , a draught of forward and aft . She was only slightly heavier than the " Charlemagne " class and displaced normally , and at full load , 700 metric tons more than the earlier ships . " Iéna " was fitted with large bilge keels , but was reported to roll considerably and pitch heavily , although this is contradicted by the ship ' s captain ' s report of November 1905 : " From the sea - keeping point of view the " Iéna " is an excellent ship . Pitching and rolling movements are gentle and the ship rides the waves well . " Propulsion . " Iéna " used three vertical triple expansion steam engines built by Les Forges et Chantiers de la Méditerranée , one engine per shaft . Each shaft drove a three - bladed propeller that was in diameter on the wing shafts and in diameter on the center shaft . The engines were powered by twenty Belleville water - tube boilers at a working pressure of . The engines were rated at a total of and produced during the ship ' s sea trials . " Iena " reached a top speed of on her trials . She carried a maximum of of coal which allowed her to steam for at a speed of . The ship ' s 80 - volt electrical power was provided by 600 - ampere and 1200 - ampere dynamo s . Armament . Like the " Charlemagne " class which preceded her , " Iéna " carried her main armament of four , 40 - calibre Canon de 305 mm Modèle 1893 / 96 gun s in two twin - gun turret s , one each fore and aft . The guns fired projectiles at the rate of 1 round per minute at a muzzle velocity of . This gave a range of at the maximum elevation of 15° . The magazines stored 180 shells per gun , enough for three hours of fighting . The ship ' s secondary armament consisted of eight 45 - calibre Canon de 164 mm Modèle 1893 guns , which were mounted in individual casemate s . The guns fired , shells at a muzzle velocity of to a maximum range of . A total of 1606 rounds were carried , enough for three hours of fighting at the practical 1 – 2 rounds per minute per gun . " Iéna " also carried eight , 45 - calibre Canon de 100 mm Modèle 1893 gun s in shielded mounts on the shelter deck . These guns fired a projectile at , which could be trained up to 20° for a maximum range of . Their theoretical maximum rate of fire was six rounds per minute , but only three rounds per minute could be sustained . 2074 shells were carried to ensure three hours of fire . The guns were above the waterline . " Iena " s anti - torpedo boat defences consisted of 16 40 - calibre Canon de 47 mm Modèle 1885 Hotchkiss guns , fitted in platforms on both masts and on the superstructure . They fired a projectile at to a maximum range of . Their theoretical maximum rate of fire was fifteen rounds per minute , but only seven rounds per minute sustained . 15 , 000 shells were kept in the magazines . Admiral Marquis criticized the arrangements for the 47 mm guns in a 1903 report : The number of ready - use rounds is insufficient and the hoists are desperately slow . The 47 mm guns , much more so than the large and medium - calibre guns , will have to fight at night ; yet these are the only guns without a fire - control system designed for night operations . This is a deficiency which needs to be corrected as soon as possible . " Iena " mounted four torpedo tube s . Two tubes were submerged and the other two were above the waterline . Twelve Modèle 1889 torpedoes were carried , of which four were training models . Armour . " Iéna " had a complete waterline armour belt of Harvey armour that was high and tapered from the maximum thickness of that covered amidships to at the ship ' s ends . The lower edge of this belt was a uniform in thickness . The upper armour belt was in two strake s , the lower 120 mm thick and the upper . Their combined height was amidships . The maximum thickness of the armoured deck was 80 mm and the fore and aft armoured transverse bulkheads were thick . The main turret armour ranged from in thickness with a roof and the ammunition shafts were protected by of armour . The casemates for the 164 mm guns were 90 mm thick and their ammunition tubes had of armour . The conning tower face had of armour and its sides were 250 mm thick . Its roof was protected by two layers of armour , each thick . The communications tube was protected by 200 mm of armour . History . " Iéna " was laid down at Brest on 15 January 1898 after being authorized on 3 April 1897 . She was launched on 1 September 1898 , but did not enter service until 14 April 1902 . " Iéna " was assigned to the Second Division of the Mediterranean Squadron and sailed for Toulon five days later . En route , the ship suffered from a number of problems with her rudder and had to be docked for repairs once she arrived at her destination . After the completion of the repairs the ship began a series of port visits in France and French North Africa which would be repeated for most of her career . " Iena " participated in the fleet review off Naples in April – May 1904 on the occasion of the visit of the President of France with King Victor Emmanuel III of Italy . Afterwards , the Mediterranean Squadron cruised the Levant , calling in Beirut , Suda Bay , Smyrna , Mytilene , Salonika and Piraeus . In April 1906 , she was dispatched to provide assistance to Naples after the eruption of Mount Vesuvius . Loss . On 4 March 1907 " Iéna " was moved into dry dock No . 2 in the Missiessy Basin at Toulon to undergo maintenance of her hull as well as inspection of her rudder shaft . Eight days later , beginning at 1 : 35 a . m . and continuing until 2 : 45 , a series of explosions began in the port No . 5 100 - millimetre magazine of the " Iéna " which devastated the ship and the surrounding area . Because the ship was in a dry dock it was initially impossible to flood the magazines . The commanding officer of the battleship , which was moored nearby , fired a shell into the gate of the dry dock in an attempt to flood it , but the shell ricocheted without holing the gate . The dock was finally flooded when Ensign de Vaisseau Roux ( who was killed shortly afterward by fragments from the ship ) managed to open the sluice gates . The , moored in the No . 1 dock beside the " Iéna " , almost capsized under the strength of the blasts . The origin of the first explosion was traced to Powder B , a nitrocellulose - based propellant used in the ammunition , which tended to become unstable with age , and self - ignite . It was estimated that 80 % of the contents of the ship ' s magazines were the suspect powder at the time of the accident . The explosion and loss of 120 lives , including two civilians killed by fragments in the suburb of Le Pont Du Las , triggered a major scandal , dubbed " the gunpowder scandal " ( ) . As a result Gaston Thomson , the Navy Minister , was forced to resign . A similar accident later caused the loss of the in 1911 . Disposal . The multiple explosions gutted the superstructure between the mainmast and the rear funnel and collapsed the superstructure surrounding the mainmast . The ship ' s side between Frames 74 and 84 was ripped open down to the lower edge of the armour belt and all the machinery in this area was destroyed . After it was estimated that it would take seven million francs and two years to fully repair the " Iéna " it was decided to decommission the ship and use her as a target ship . All useful equipment was removed and she was towed to a mooring off the Île des Porquerolles where she was used as a target to test the effectiveness of the latest design of armour - piercing shell s beginning on 9 August 1909 . After the completion of numerous tests , and with the " Iéna " close to foundering , she was towed to deeper water . While under tow " Iéna " capsized and sank on 2 December 1909 . The rights to the wreck were sold and she was subsequently broken up and salvaged between 1912 and 1927 .