Char B1 The Char B1 was a French heavy tank manufactured before World War II . The Char B1 was a specialised heavy break - through vehicle , originally conceived as a self - propelled gun with a 75 mm howitzer in the hull ; later a 47 mm gun in a turret was added , to allow it to function also as a " Char de Bataille " , a " battle tank " fighting enemy armour , equipping the armoured divisions of the Infantry Arm . Starting in the early twenties , its development and production were repeatedly delayed , resulting in a vehicle that was both technologically complex and expensive , and already obsolescent when real mass - production of a derived version , the Char B1 " bis " , started in the late thirties . Although a second uparmoured version , the Char B1 " ter " , was developed , only two prototypes were built . Among the most powerfully armed and armoured tanks of its day , the type was very effective in direct confrontations with German armour in 1940 during the Battle of France , but slow speed and high fuel consumption made it ill - adapted to the war of movement then being fought . After the defeat of France captured Char B1 ( bis ) would be used by Germany , with some rebuilt as flamethrowers or mechanised artillery . Development and production . The Char B1 had its origins in the concept of a " Char de Bataille " conceived by General Jean Baptiste Eugène Estienne in 1919 , e . g . in his memorandum " Mémoire sur les missions des chars blindés en campagne " . It had to be a " Battle Tank " that would be able to accomplish a breakthrough of the enemy line by destroying fortifications , gun emplacements and opposing tanks . In January 1921 a commission headed by General Edmond Buat initiated a project for such a vehicle . To limit costs , it had to be built like a self - propelled gun , with the main weapon in the hull . To minimise the vehicle size this gun should only be able to move up and down with the horizontal aiming to be provided by turning the entire vehicle . The specifications included : a maximum weight of thirteen metric tonnes ; a maximum armour thickness of 25 millimetres ; a hull as low as possible to enable the gun to fire into vision slits of bunkers ; a small machine gun turret to beat off enemy infantry attacks , at the same time serving as an observation post for the commander and a crew of at most three men . Two versions should be built , the one a close support tank armed with a 75 mm howitzer , the other an antitank - vehicle with a 47 mm gun instead . The French industry was very interested in the project . In the past this had often led to much non - constructive rivalry . Estienne , who in the war had personally witnessed the dismal effects of such a situation , was determined to avoid a repetition this time . He used his position as Inspector - General of the Tanks to enforce the so - called " Estienne accord " on the industrialists , ordering them to " reach a mutual understanding , free from any spirit of industrial competition " . To be allowed to join they had to agree beforehand to relinquish any patents to the Army , which would be free to combine all projects into a single type . In exchange industry were promised very large orders of no less than a thousand vehicles . On these conditions four projects were started in 1921 : two by a cooperation between Renault and Schneider : the SRA and the SRB , one by FAMH ( " Forges et Aciéries de la Marine et d ' Homécourt " , better known as " Saint Chamond " ) and the last by FCM ( " Forges et Chantiers de la Méditerranée " ) , the FCM 21 . Renault and Schneider would each get to produce 250 units , FAMH and FCM each 125 . A fifth producer , " Delaunay - Belleville " , of which the project ( an improved FT 17 ) had been rejected beforehand , would be allowed to make 83 tanks ; the remaining 167 would be allotted at the discretion of the French State . On 13 May 1924 the four prototypes were presented at the " Atelier de Rueil " , where they were compared , each having to drive over a twenty kilometre test course . Immediately it became evident that their technical development had been insufficient , most breaking down ; the SRA even started to fall apart . Maintenance was difficult because the engines were inaccessible . All projects used a three men crew but differed considerably in size , form and the solution chosen to laterally point the gun . The SRA was the heaviest vehicle with 19 . 5 metric tonnes . Its length was 595 centimetres , its height 226 cm and its width 249 cm . It had a 75 mm howitzer in the right side of the hull and a cast , 30 mm thick , turret with two machine - guns . It was steered by an epicyclical transmission combined with hydraulically reinforced brake disks — during tests this failed to provide the desired precision . Seen from the front it already was very similar to the final model , but its side view was more like that of the British Medium Mark D , including the " snake track " - system , with the drive wheel higher than the idler in front . The suspension used leaf springs . A Renault six - cylinder 180 hp engine ( a bisected 12V aircraft engine ) allowed for a maximum speed of 17 . 5 km / h ; a four hundred litre fuel tank for a range of 140 kilometres . The SRB was a somewhat larger vehicle , six metres long , 228 centimetres high and 2 , 5 metres wide . It was nevertheless lighter at 18 . 5 tonnes , a result of having a smaller 47 mm gun — it thus was the antitank - version . Using the same engine , its speed was accordingly slightly higher at 18 km / h . More limited fuel reservoirs holding 370 litres decreased the range to 125 kilometres . It used an advanced hydraulic suspension system and the hydraulic Naeder - transmission from the " Chaize " company combined with a " Fieux " clutch and Schneider gear box . It used modified FT 17 tracks . The upper track run was much higher , creating enough room for a side door on the left . The FAHM prototype resembled the contemporary Vickers Medium Tank . It weighed seventeen tonnes , was 520 centimetres long , 240 cm high and 243 cm wide . It used a hydropneumatic suspension . Despite a weaker Panhard engine of 120 hp it still attained a speed of 18 . 2 km / h . Fuel reservoirs of just 230 litres limited its range to a mere seventy kilometres . The 75 mm howitzer was placed in the middle of the hull and steered by providing each snake track with its own hydraulic " Jeanny " transmission . On top was a riveted machine - gun turret with 25 mm armour . The lightest prototype was the FCM 21 at 15 . 64 tonnes . It resembled a scaled - down Char 2C , the giant tank produced by the same company . It was very elongated with a length of 6 . 5 metres and width of 205 centimetres . A rather large riveted turret with a stroboscopic cupola , adopted from the Char 2C , brought its height to 252 centimetres . Like the superheavy tank it had no real spring system for the twelve small wheels per side . Separate clutches for each snake track allowed to horizontally point the 75 mm howitzer in the middle of the hull . It used the same Panhard engine as the FAHM type and its speed was the lowest of all at 17 . 4 km / h . However , five hundred litre reservoirs allowed for the best range at 175 kilometres . March 1925 Estienne decided to base the future production type on the SRB , as regarded the general form and mechanical parts . However , it would be fitted with the 75 mm gun , a Holt - track to be developed by FCM , which company had completed a special research programme aimed at optimising weight distribution , and the FAMH - suspension ( later this would again be discarded ) . Estienne also had some special desires : a track tension wheel should be fitted , adjustable from the inside , and a small gangway from the fighting room should improve the accessibility of the engine compartment . Furthermore the front armour should be increased to 40 millimetres . In November 1925 Renault was given the order to build a wooden mock - up , that was finished early 1926 . On 27 January 1926 it was decided to build three prototypes of what was provisionally called a " Tracteur 30 " , a final design by engineer Alleaume of the Schneider company , cooperating with the STCC ( " Section Technique des Chars de Combat " ) . The first was to be delivered by Renault , the other two by FCM and FAHM respectively . The same year the " Direction de l ' Infanterie " in the Plan 1926 redefined the concept of a " Char de Bataille " . There would be a greater emphasis on infantry support , implying that the antitank - capacity was secondary and no armour increase was necessary . The weight was to be limited to 22 metric tonnes and the speed might be as low as 15 km / h . However , a radio set would have to be fitted to better direct and coordinate its actions ; therefore a fourth crew - member was needed . On 18 March 1927 the contracts for the three prototypes were signed . The hull of first Renault vehicle , made of softer boiler plate instead of armour steel to simplify changes , was in January 1929 finished apart from the armament . It was delivered in March . The separately produced cast turret was delivered on 23 April . The howitzer could only be fitted in April 1930 . This prototype was allotted the series number N° 101 . N° 102 , the production of which FAMH had shifted to Renault , was delivered soon after ; in September 1930 FCM delivered N° 103 , constructed by the " Atelier de Mépanti " at Marseille . One of the vehicles was fitted with an alternative 75 mm Schneider gun instead of the 75 mm St Chamond M 21 from FAMH . Testing on the first prototype had already begun before the other two were delivered , or even its main armament was fitted . It had with 24 , 750 kilogrammes a weight higher than specified but could nevertheless reach a top speed of 24 km / h . From 6 May until August 1930 the " Commission d ' Experiences des Matériels de Chars " carried out a further test programme on what was now officially called the Char B — the " B " not referring to " Bataille " but to a general classification code . The commission was largely satisfied with the vehicle , though many smaller problems were detected that had to be improved . The FCM prototype featured several alternative technologies : a " Winterthur " transmission , a " Citroën " clutch and a " Sulzer " diesel engine , later replaced by a " Clerget " diesel . All of these systems would prove to be more unreliable than the original concept and were ultimately rejected . The three vehicles were not only used for technological but also tactical experimentations . Together with the Char D1 pre - series they represented the only modern tanks in France and the Army was naturally very interested in what lessons could be learned from them about future warfare , outlining the concept of a " Char de Manoeuvre " . Neither " Char de Bataille " nor " Char de Manoeuvre " are official type designations ; they refer to the tactical concepts only . . In October 1931 a small unit was formed , the " Détachement d ' Experimentation " in which the prototypes were united from December , using the " Camp de Châlons " as a base to see how they could be used in winter conditions . Afterwards they on their own power drove to the " Atelier de Rueil " for repairs . In September they participated in the Champagne summer manoeuvres as a " Détachement Mécanique de Combat " ; from 4 May 1933 N° 102 en 103 together formed a " Détachement d ' Engins Blindés " to perform tactical experiments in the army bases of Coëtquidan and Mourmelon as part of a motorised light division , followed by comparable experiments in April 1934 at Sissonne . Technical aspects were not forgotten during these tests and it was established they could attain an average road speed of 19 km / h , cross a trench 2 , 4 metres wide and wade through a 105 centimetres deep stream . The prototypes were again extensively altered to meet changes in specifications . On 6 April 1934 the first order was made for seven tanks of a Char B1 . The " B1 " refers to the fact that there were other simultaneous projects to develop improved types : the Char B2 , B3 and B B . The Char B1 was manufactured by several firms : Renault ( 182 ) , AMX ( 47 ) , FCM ( 72 ) , FAMH ( 70 ) and Schneider ( 32 ) . Although it was the main producer , Renault had not exclusively designed the tank . Therefore the official name was not " Renault B1 " as often erroneously given . It was a very expensive tank to build : the per unit cost was about 1 . 5 million French francs . In France at the time two schools of thought collided : the first wanted to build very strong heavy tanks , the other a lot of cheap light tanks . Both sides managed to influence procurement policy to the end that not enough tanks were built of either category , to the exasperation of men like Colonel Charles de Gaulle who wanted to build more of the medium Char D2 , with a third of the cost of the Char B1 bis , but armed with the same 47 mm gun . Tactical function . The outer appearance of the Char B1 reflected the fact that development started in the twenties : like the very first tank , the British Mark I tank of World War I fame , it still had large tracks going around the entire hull and large armour plates protecting the suspension — and like all tanks of that decade it had no welded or cast hull armour . The similarity resulted partly from the fact that the Char B1 was a specialised offensive weapon , a break - through tank optimised for punching a hole into strong defensive entrenchments , so it was designed with good trench - crossing capabilities . The French Army thought that dislodging the enemy from a key front sector would decide a campaign , and it prided itself on being the only army in the world having a sufficient number of adequately protected heavy tanks . The exploitation phase of a battle was seen as secondary and best carried out by controlled and methodical movement to ensure superiority in numbers , so for the heavy tanks also mobility was of secondary concern . Although the Char B1 had for the time of its conception a good speed , no serious efforts were made to improve it when much faster tanks appeared . More important than the tank ' s limitations in tactical mobility , though , were its limitations in strategic mobility . The low practical range implied the need to refuel very often , limiting its operational capabilities . This again implied that the armoured divisions of the Infantry , the " Divisions Cuirassées de Réserve " , were — despite their name that merely reflected the fact that they had originally been planned to be raised in a " secondary " mobilisation — not very effective as a mobile reserve and thus lacked strategic flexibility . They were not created to fulfill such a role in the first place , which was reflected in the small size of the artillery and infantry components of the divisions . The one - man turret . Another explanation of the similarity to the British Mark I lies in the Char B1 ' s original specification to create a self - propelled gun able to destroy enemy infantry and artillery . The main weapon of the tank was its 75 mm howitzer , and the entire design of the vehicle was directed to making this gun as effective as possible . When in the early 1930s it became obvious that the Char B1 also had to defeat counterattacking enemy armour , it was too late for a complete redesign . The solution was to add the standard cast APX - 1 turret which also equipped the Char D2 . Like most French tanks of the period ( the exception being the AMC 34 and AMC 35 ) the Char B thus had a small one - man turret . Today this is typically seen as one of their greatest flaws . The commander , alone in the turret , not only had to command the tank , but also to aim and load the gun . If he was a unit leader , he had to command his other tanks as well . This is in contrast with the contemporary German , British and to a lesser extent Soviet policy to use two or three - man turret crews , in which these duties were divided amongst several men . The other nations felt that the commander would otherwise be over - tasked and unable to perform any of his roles as well as the commanders of tanks with two or three - man turret crews . Whether this left the Char B1 less - formidable in actual combat than a review of its impressive statistics suggests , is difficult to ascertain . In 1940 , the vast majority of Char B1 combat losses were inflicted by German artillery and anti - tank guns . In direct meetings with German tanks the Char B1 usually had the better of it , sometimes spectacularly so as when on 16 May a single tank , " Eure " ( commanded by Captain Pierre Billotte ) , frontally attacked and destroyed thirteen German tanks lying in ambush in Stonne , all of them Panzer III s and Panzer IV s , in the course of a few minutes . The tank safely returned despite being hit 140 times . Similarly , in his book " Panzer Leader " , Heinz Guderian related an incident , which took place during a tank battle south of Juniville : " While the tank battle was in progress , I attempted , in vain , to destroy a Char B with a captured 47 - mm anti - tank gun ; all the shells I fired at it simply bounced harmlessly off its thick armor . Our 37 - mm and 20 - mm guns were equally ineffective against this adversary . As a result , we inevitably suffered sadly heavy casualties " . The French favoured small turrets despite their shortcomings , as they allowed for much smaller and thus cheaper vehicles . Although the French expenditure on tanks was relatively larger than the German , France simply lacked the production capacity to build a sufficient number of heavier tanks . The Char B1 was expensive enough as it was , eating up half of the infantry tank budget . Variants . Char B1 . The original Char B1 had frontal and side armour up to 40 mm thick . The vehicle had a fully traversing APX1 turret with a 47 mm L / 27 . 6 SA 34 gun . This had a poor anti - tank capability : the thirty APHE ( Armour Piercing High Explosive ) rounds among the fifty the tank carried had a maximum penetration of about 25 mm . In addition , it was armed with a 75 mm ABS 1929 SA 35 gun mounted in the right - hand side of the hull front and two 7 . 5 mm Châtellerault M 1931 machine guns : one in the hull and the other in the turret . The 75 mm L / 17 . 1 gun , that could fire both a HE and the APHE " Obus de rupture Modèle 1910M " round , had a limited traverse of only one degree to the left or the right ( equating to about 18 metres at 500 m range ) . It was laid onto target by the driver ( provided with the gun sight ) through the Naeder hydraulic precision transmission . The traverse had only been made possible in order to precisely align the gun barrel with the sight beforehand . The 75 mm gun had its own loader — the remaining two crew members were the radio operator and the commander , who had to load , aim and fire the 47 mm gun while commanding the vehicle ( and in the case of platoon leaders , command other vehicles as well ) . The fighting compartment had the radio set on the left and an exit hatch in the right side . All vehicles had the ER53 radio telegraphy set , which used Morse Code only . A hatch in the rear bulkhead gave access to a corridor ( under which nineteen 75 mm rounds out of a total of eighty were stowed ) in the engine room to the right of the engine , which was officially rated at , but had an actual output of . Each tank had its own team of three mechanics ; in battle some of these might join the regular crew . The suspension was very complex with sixteen road wheels per side . There were three large central bogies , sprung by a vertical coil spring . Each central bogie carried two smaller ones . The three vertical springs moved through holes in a horizontal beam , to both extreme ends of which road wheels were attached by means of leaf springs : three at the front and one at the back . The high track run gave the tank an old fashioned look , reflecting its long development time . It had a maximum speed of 28 km / h and a weight of 28 metric tons . The range was about 200 km . A total of 34 vehicles were built from December 1935 until July 1937 . They had series numbers 102 to 135 . Chassis number 101 was kept apart to build the Char B1 ter prototype . Char B1 bis . The Char B1 bis was an upgraded variant with thicker armour at 60 mm maximum ( 55 mm at the sides ) and an APX4 turret with a longer - barrelled ( L / 32 ) 47 mm SA 35 gun , to give the tank a real anti - tank capacity . It was the main production type : from 8 April 1937 until June 1940 369 units were delivered out of a total order for 1144 , with series numbers 201 to 569 . Before the war manufacture was slow : only 129 had been delivered on 1 September 1939 . The monthly delivery was still not more than fifteen in December ; it peaked in March 1940 with 45 . The Char B1 bis had a top speed of provided by a petrol engine . The first batch of 35 Char B1 bis used the original engine but from 1938 to May 1940 they were slowly re - equipped . Its weight was about 31 . 5 metric tons . The operational range was about which was similar to other tanks of the period . At the three fuel tanks ( total capacity of would be exhausted in six hours . To improve matters , at first , trailers with an 800 litre auxiliary fuel tank were towed but this practice was soon abandoned . Instead Char B1 units included a large number of fuel trucks and TRC Lorraine 37 L armoured tracked refuelling vehicles specially designed to quickly refuel them . The last tanks to be produced in June had an extra internal fuel tank . To cool the more powerful engine the Char B1 bis had the air intake on the left side enlarged . It is often claimed this formed a weak spot in the armour , based on a single incident on 16 May near Stonne where two German 37 mm PAK guns claimed to have knocked out three Char B1 ' s by firing at the intakes at close range . The air intake was a thick assembly of horizontal slits alternately angled upwards and downwards between 28 mm thick armour plates , and as such intended to be no more vulnerable than the normal 55 mm side plates . Over the production run the type was slowly improved . Tanks number 306 to 340 carried 62 47 - mm rounds ( and the old complement of 4 , 800 machine gun rounds ) ; later tanks 72 and 5 , 250 . However the B1 bis had fewer 75 mm rounds compared to the earlier B1 : 74 instead of eighty , normally only seven of which were APHE ammunition . Early in 1940 another change was made when the ER53 radio was replaced by the ER51 which allowed spoken wireless communication . The company and battalion command tanks also had an ER55 for communication with higher command . The crews of the " 1re DCR " kept their old sets however , preferring them because the human voice was drowned by engine noise . Char B1 ter . Development of the Char B1 ter was started at the same time as production funds were given for the " bis " with the intention of providing a tank armoured to 75mm . A design with sloped and welded 70 mm armour , weighing 36 . 6 metric tons and powered by a engine was meant to replace the B1 bis to accelerate mass production , a change first intended for the summer of 1940 and later postponed to March 1941 . In the course of the redesign , space was provided for a fifth crew member , a " mechanic " . Cost was reduced by omitting the complex Neader transmission and giving the hull gun a traverse of five degrees to each side instead . The first prototype was shown in 1937 . Only three prototypes could be partly finished before the defeat of France . In May 1940 it was agreed to deliver nine Char B1 ' s each month to Britain in exchange for a monthly British production of the " H 39 " . The three prototypes were lost after having been evacuated on 17 June 1940 , their ship the " Mécanicien Principal Carvin " being bombed by the Germans in the Gironde on 21 June . Operational history . The Char B1 served with the armoured divisions of the Infantry , the " Divisions Cuirassées de Réserve " . These were highly specialised offensive units , optimised to break through fortified enemy positions . The mobile phase of a battle was to be carried out by the armoured divisions of the Cavalry , equipped with the SOMUA S35 . The First and Second DCR had 69 Char B1 ' s each ; the Third 68 . The 37th " Bataillon de Chars de Combat " , serving with 1DCR , was at first equipped with the original B1 ; these vehicles were refitted with the longer SA 35 gun in the spring of 1940 . The turret type designation was changed to APX1A . The battalion was re - equipped with the Char B1 bis and in May reinforced by five of the original tanks . After the German invasion several ad hoc units were formed : the 4DCR with 52 Char B1 ' s and five autonomous companies ( 347e , 348e , 349e , 352e and 353e " Compagnie Autonome de Chars " ) with in total 56 tanks : 12 B1 ' s and 44 B1 bis . Also 28BCC was reconstituted with 34 tanks . The regular divisions destroyed quite a few German tanks , but lacked enough organic infantry and artillery to function as an effective mobile reserve . A number of Char B1 ' s ( 161 ) were captured by the Germans during the Fall of France . These were later pressed into service as second line and training vehicles under the name of " Panzerkampfwagen B - 2 740 ( f ) " . Sixty became platforms for flamethrower s as " Flammwagen auf Panzerkampfwagen B - 2 ( f ) " . Sixteen were converted into 105 mm self - propelled artillery . Ordinary tank versions were also frequently modified . For example , additional armour was placed above the main gun , and a winch mechanism was added behind the turret . One unit , " Panzer - Abteilung 213 " , was equipped with the Char B1 bis and deployed on the Channel Islands from 1941 to 1945 . One of their tanks is displayed by the Bovington Tank Museum , though repainted in French colours . In German service , the tank saw action in the Balkans Campaign and the Eastern Front , initially during Operation Barbarossa , the flamethrower version from 1942 onwards . The principal German units that used the Char B1 bis : Italy independently from Germany captured eight Chars B1 bis when in October 1940 an Italian worker disclosed to the Italian Armistice Commission that they in July had been hidden in a cave near Les Baux - de - Provence . These vehicles , six of which lacked the turret , were tested but probably not operationally used by Italy . After the Allies had invaded France in 1944 , some B1s were recaptured . Several were used on an individual and incidental basis by resistance forces , such as those fighting the German garrison of Paris in August 1944 . On 7 October 1944 , the Provisional Government of the French Republic formed the 13th Dragoon Regiment of the Free French Forces . The majority of the regiment fielded SOMUA S35 cavalry tank s , but Captain Edmond Voillaume ' s 2nd Company was equipped with 19 B1 bis tanks , which included a mixture of standard and German modified B - 2s . They were stationed in Orléans until 2 April 1945 , when they were mobilized for the Allied siege of La Rochelle . The tanks were effective in the attack on Royan on 15 April 1945 , using their 75 mm guns for fire support , while targeting pillbox es with their 47 mm guns . After that , 2nd Company accompanied troops on an assault on Pontaillac on 17 April , followed by an attack on the German stronghold at La Rochelle between 29 April and 8 May . Voillaume was awarded the Distinguished Service Cross for his actions . After the war , the 13th Dragoon Regiment was stationed in the French occupation zone of Allied - occupied Germany as part of the French 3rd Armoured Division . It was eventually disbanded in the German town of Wittlich in April 1946 . Surviving vehicles . Today eleven vehicles survive , one Char B1 and ten Char B1 bis . The last surviving Char B1 can be seen at the " Association pour la Sauvegarde du Patrimoine Historique et Militaire " ( ASPHM ) , near Strasbourg , in France . It was previously at the Fort de Seclin . It is in a bad condition , with parts like the main gun missing . It was salvaged from a firing range , but will be restored by the owner . Ten Char B1 bis can be seen in various places in Great Britain and in France :