Talk:SOMUA S35

Importance of turret design

The fact that the Somua S-35 did only have a single man turret hasen´t received a sufficient emphasis so far. This is about situational avareness. For comparison think about Panzer III, which had a three man turret, hence the same task divition which is used today in M1 Abrahams. The commander in the cupola is the lookout, tells the driver which way to turn, wether to drive faster or slower. He finds the enemy targets, tells the gunner which way to rotate the turret. The gunner and the loader together ensure a reasonable rate of fire. The commander makes sure nobody can surprice the tank. In the case of the Somua, however let´s imagine the commander has sighted an enemy. He tells the driver to stop, because once he stops looking from the top he looses his ability to look all around and risks loosing track of his would be targets. He loads the gun. He then looks through the gunsight, rotates the turret till the enemy enters the gunsight. Now, while he is only looking through the gunsight he has a tunnel vision and tunnel avareness. As he has a good gun and a good armour for the time his chances of destroying a Panzer III are good once he has found it in his gunsight. However, once he has shot once, it takes him longer to shoot again than the Germans, if there are more of them. The worst part is though that each time he loads, he isn´t even looking through his gunsight so he is blind at those times. With the surprice lost a competent German will seek to move into his blindspot. If the terrain has some consealment options, theyr chances subsequently will be pretty good to stalk the Somua and destroy it from behind. So a lone Somua will be at a very severe tactical disadvantage due to the single man turret problem. In a group of tanks vs. group of tanks fight, the main disadvantage will have been less rate of fire. As long as they would have staied together, each would have been able to guard the other, they would have been able to make good use of theyr guns and armour. But once it became a one on one melee, with a lot of confusion thrown in the advantage would have gone to the Germans with theyr superior situational avareness.194.144.20.188 (talk) 02:06, 16 January 2008 (UTC)

Yes, this is as such a reasonable hypothesis, much mentioned in the postwar literature and therefore mentioned in the article. However, the French at the time did not consider it very relevant — and this is also mentioned. Good empirical data are absent and we simply do not know whether it in reality had any significant negative effects. This is very largely dependent on the intensity and change speed of the battlefield situation, which might well have been rather low in this period. However I can highlight some speculative points here: the main problem in respect to situational awareness must have been the lack of a hatched cupola. To have a good view of his surroundings the commander had to sit outside of the turret on the back hatch. This made him vulnerable and slow to react. Having to fulfil the rôle of the gunner obviously meant there was less time to look around — German reports indeed emphasize they could approach French tanks surprisingly close before provoking any reaction. However he would not necessarily be blind when loading, as the radio operator would hand him the round and the commander could shove it in with one hand. Not having to coordinate the actions of the turret crew also would have gained him some time. The Germans indeed tried to get behind the SOMUAs but not so much to destroy them — the French tank was just as heavily armoured at the back — but to drive onwards and defeat them by the operational collapse of their position. That's what manoeuvre warfare is all about after all... Engagements would have been rare and avoided if possible; and mêlées even more exceptional. Only a tiny fraction of all S 35s was destroyed by a PzKpfw III--MWAK (talk) 08:28, 16 January 2008 (UTC)

Now, the French highcommand is certain to have been wrong that a single man turret was of litle issue. Now, while the single man turret flaw is usually mentioned, I think people aren´t giving it a sufficient weight as a flaw. It´s in my opinion really pretty darn bad from the perspective of actual battlefield usefulness. The reason for the lack of empirical data, is how few the tank battles in 1940 were. The surprice the Germans gave the allies in 1940, and the success of theyr advance such, that most of the allied tanks were simply lost when logisticks broke down and units were unable to refuel. One therefore must infer the effect of such a flaw from the kind of battles that occured later in the war. However, the pace of tank actions during WWII tended to be really rapit, both in the desert war and in USSR. So, tactical avareness was undoubtedly very important. In Russia, close action melee wasn´t infrequent when the Germans encounterd mass charges cavalry style like. If the war in France had progressed according to the Schlieffen plan, it would have lead to massive tank actions of the kind which happened in Russia and in the desert. So I think there is some relevance in making such a comparison. I repeat, I think that the significanse of the single turret problem has been underestimated by those who have been writing books about WWII tanks. "Not needing to coordinate the actions of the turret crew, gains him time" - that I think absurd. A commander doesn´t need to order his turret crew in every litle detail. A well trained crew knows what to do, once the commander has told them where the target is. They will clearly be much faster, than the commander of the French tank who is also doing those jobs as well as commanding. So the Somua had the same armour thickness on the whole hull. That´s very unusual. In other nations tanks tended to pryoritize the armour thickness, with thick at front, thinner on the sides, thinner than that on the back and even thinner than that underneath. So a Mathilda II could be destroyd by a shot in the rear end. So, the Germans then simply drove around the Somuas, trusting that the French commander´s tunnel vision and lack of battle avareness would allow them to do that unscathed, leaving the Somuas behind. The Panzer III being faster could have managed that. Mind you, they would not have been able to pull that kind of manoeuvre off if the French tank had had a three man turret, you surelly realize that? In my opinion the Somua S-35 was conceptually outdated.

Let´s for fun make a comparison between medium tanks that were available in 1940. I´ll grant in each category the score ten for the best category achievment. Lowest category score gets 1.

Matilda II Armour. 10 (Maximum 78mm/minimum 14mm) Mobility. 1 Power/weigh. 1. (174hp./26.926kg) Range. 256km. 5 Firepower 1. 2 man turret. 5. Score: 23

Panzer III. Armour. 5. (Maximum 30mm/minimum 14,5mm) Mobility 8. Power/weight. 7. (320hp/19.400kg) Range. 165 km. 1. Firepower 1. 3 man turret. 10. Score: 32

Bt 7. Armour 1. (Maximum 22mm/minimum 10mm) Mobility. 10 Power/weight. 10 (500hp/13.900kg) Range 430km. 10. Firepower 10. 2 man turret. 5. Score: 46

Somua S-35 Armour 8. (56 mm turret/41 mm hull) Mobility. 5. Power/weight. 5. (190hp/20.048kg) Range 257km. 5. Firepower. 10. 1 man turret. 1. Score: 34

Now, this is only my comparison. The data is taken from David Miller´s, Tanks of the world from world war I to the present day. But it indicates my personal preference for the Bt series tanks which as you note had greater number of star qualities. They had comparable firepower to the Somua, but much superior range, mobility, speed and a 2 man turret. Theyr flaw was the thin armour, but that was later rectified with addon armour. To rectify the major flaw of the Somua would have been a tougher issue, necessiating a completelly new turret. So in my opinion the Bt series is not only the most prolific tanks of the 30s but also the best.194.144.20.188 (talk) 23:22, 16 January 2008 (UTC)

Well, the point is that you are making some reasonable assumptions but you don't really know whether they are true! Indeed pitched battles were rare. But on the one occasion a large tank battle materialised, in the Battle of Hannut, the S 35 gave a reasonably good account of itself. In fact the commander of a turret crew was expected to supervise the fire engagement quite rigidly. Your comparison of tanks is obviously not strictly scientific: like most listing it only gives the illusion of quantitative exactness...BT-losses were prodiguous, not only from poor maintenance but also because that (on paper) single minor flaw, thin armour, proved to be fatal in actual battle. I suspect the French choice for thicker armour was in fact justified; an equally expensive tank with a three-men turret would only have had 25 mm armour. If the battle intensity was low this would not have been offset by a higher potential fire rate. As an aside, the maximum speed of the S 35 equalled that of the PzKpfw. III (the latter's engine had an output of 265 hp). And you can't blame the French High Command for everything ;o) --MWAK (talk) 09:26, 17 January 2008 (UTC)

Now, decided to refresh my memory about that particular battle, and indeed the Somua appears to have been utlized with considerable skill by the French commander there. The French army in that area was in a defencive position. The Somuas apparently on the eve of the battle dug down, with the turret alone showing. The Somuas appear to have been able to open up on the German tanks at a range beyond the effective range of the 37mm gun of the Panzer III. The Somuas were also used when the French forces counterattacked. What the battle shows is how bad was the earlyer decision of the German highcommand to put the Panzer III into production with the 37mm gun instead of the 50mm it was designed for. With that gun the result of the Panzer III vs. Somua actions would have been quite different, as with 3 man turrets the Germans would have been firing about 3 rounds for every 1 fired by the Somuas. Now, the Somua is a really strange tank. It´s really weird to produce it with uniform armour thickness. The turret appears also to have had a uniform armour thickness, even thicker than the hull. Clearly a larger turret of uniform thickness would have been to heavy. However, a turret with only thick armour at the front would not have been to heavy. You see, the Somuas that were weterans of that battle frequently had suffered numerous hits up to 20 that didn´t penetrate. That does tell me that with a proper gun they would have been smoking wrecks at the end of the battle. The way I understand it, indeed they were saved by theyr armour and the lover rate of fire dues to the single man turret operation didn´t prove to do much harm that time. But the emphasize that the share number of hits that had nicked theyr armour appears to me to indicate that outcome would have been quite different if theyr opponent had been equipped with a proper weapon. Now, about the BTs once the German invation began, if operated with comparable skill, they ought at least have been a match for the Panzer III as both types of tank could put a hole into each other´s armour at theyr maximum engagement ranges. To put that into the other perspective the BT would also have been able to put a hole into the armour of the Somua at its maximum engagement range. So, basigly the armour strength is only of consequence if it is strong enough to keep the shots out. The armour of the Somua was able to do so due to the PanzerIII having been undergunned in France. Mind you the armour of the Somua wasn´t especially thick, the Panzer III really simply was undergunned, the armour of the Mathilda II was thicker upfront. It was only relativelly strong in comparison to what it was encountering. However, about the Soviet armies they were largelly undone by the insane orders they received from STAVKA on Stalin´s insistence, i.e. they were not allowed to retreat so they could regroup. So instead they got surrounded and all theyr equipment destroyd. In later actions, the armour of the BTs was strengthened with addon armour. One can only hypothyze about it what would have happened if instead they would have retreated and counterattacked. The Panzer III is clearly faster than the Somua, after all it´s got a superior power to weight ratio. That at the very least would have resulted in a superior cross country speed, and according to my sources it also had a greater road speed. It was the French highcommand that made curious choyses like ordering tanks with single man turrets, thus significantly reducing theyr effectiveness.194.144.20.188 (talk) 00:27, 18 January 2008 (UTC)

Yes, the imminent introduction of the 50 mm gun on the PzKpfw III was a very troubling development for the French tanks. It points to a major flaw in the French armour design: that it could not easily be upgraded. This fundamental problem was well understood and the S 40 was partially a response to it. The introduction of new types, like the Char G1, had been postponed in order not to disturb the production of the existing models.

The PzKpfw III was certainly more agile than the S 35 and its torsion bar suspension would also have ensured a higher speed in rough terrain. However, the power-to-weight ratio is as such not decisive; what is relevant is the effective engine output. The BT-7 could not, with the ammunition available in the summer of 1941 (no APCR-rounds), have penetrated the frontal armour of the latest PzKpfw III models, but would have been vulnerable to the 50 mm gun even if uparmoured. Soviet armoured units quite often counterattacked in the first phases of the battle but then suffered gruesome losses. The decision of the French High Command might have been curious :o), but reflected consensus. Apart from allowing for a more heavily armoured tank, a one man-turret also alleviated manpower shortages and facilitated mass-production of a single type for several tank models.--MWAK (talk) 07:49, 18 January 2008 (UTC)

Yeah, uniform armour would have very rapidly become unmanagably heavy. Basigly the precense of the 50mm would have made the Somua imediatelly obsolete.

Had not heard there were no armour pierching rounds available for the 45mm gun on the BT-7 in 1941. Appears a strange oversight, especially in light of the previous action with the Japanese. I naturally assumed the precense of armour pierching rounds. What source does say this? A problem with the standard armour of the BT was that it could also be penetrated by the gun of the Panzer II, which had a high rate of fire. In addition, the 37mm anti tank guns would also not have had any problem. So unskilled use would have lead to gruesome losses. But, I´d expect it to have been a match for Panzer III in a straight tank to tank action. Hmm, if they had designed the armour of the Somua in like fashion as had become the norm ellsewhere, i.e. strongest at front, weaker on the sides, weaker still at the rear, and weakest underneath and done similar for the turret; they could have made the armour considerably stronger up front were it really counted and afforded the weight as well of a larger turret without increasing the overall weight of the tank. I expect the price for such a veicle would have been about same, as about the same amount of material would have been used, but would have resulted in a much superior veicle. And they chose to compromize these other tank models in the very same fashion. I guess it looked very clever on paper.194.144.20.188 (talk) 22:41, 18 January 2008 (UTC)

The BT-series used AP-rounds in June 1941 but the APCR was not yet available. The AP would only penetrate 42 mm at 500 m distance, not enough against the later PzKpfw. III models.--MWAK (talk) 09:00, 19 January 2008 (UTC)

I understand though that up to half of the Panzer III used in 1941 were early models equiped only with 37mm gun. Though those were apparently upgunned with some alacrity once the German highcommand discovered to its dismay how effective the then brandnew Soviet tanks were, making the 37mm simply hopless, and the shorter barrel version of the 50mm marginal at best.194.144.20.188 (talk) 19:43, 19 January 2008 (UTC)

Indeed 259 of 816 PzKpfw IIIs deployed on 22 June 1941 still had the 37 mm gun. There was, I believe, an upgrade programme initiated from March 1941 with about 150 tanks rebuilt, but after most extant vehicles had been put to action, this was discontinued.--MWAK (talk) 07:34, 20 January 2008 (UTC)

A few comments to the above: 1) in 1935, one man-turrets were not a rare or unique feature, they still were the norm. 2) multiple-man turrets were not unknown in France. In fact the 1A tank prototype had introduced the 3-man turret in 1917. The same turret was operationally used after WWII on the FCM 2C tank. At the time the S35 was fielded (circa 1938), two different 2-man turrets designs were in use in France: the APX2 fitted on the AMC 35 Renault ACG1, the S35's competitor, and the APX3 fitted on the AMD 35 Panhard 178. They were both very much inferior to the APX1CE armour-wise. So why was the SOMUA only equipped with a "one man and a half" turret (strict "one-man" turrets were infantry turrets like the APX1 or APX4)? Because the French cavalry had determined the AMC should have a total crew of three. From Stéphane Ferrard's book, experience with the Renault AMC and its APX2 turret led to the conclusion than, given a 3-man crew, the 3rd man was more useful in the hull than he could be in the turret. I will double-check this and add it to the article. PpPachy (talk) 10:52, 18 January 2008 (UTC)

Practical experience with the APX2 was only gained in a very late phase with the AMC 34. Was the definite choice for the APX1 not made earlier? But I presume a preference for having the radio operator in the hull might have played a part.--MWAK (talk) 08:47, 19 January 2008 (UTC)

We were talking about medium tanks. The reason why most tanks during the 30s had a single man turret was because most tanks that equipped the peace time armies of that periot were really small, mostly machinegun armed. The British had a significant numbers of theyr Mk.VI made, to name an example. They sufficed to police the empire but they were recognized as being obsolete at the begginning of the WWII. An influential design, the Wickers 6 ton had two machine gun turrets. However, cannon armed tanks were not generally built with a single man turret. The WWI era French heavy tank was never used in anger. Yet, the French chose to produce far greater numbers of theyr single turreted cannon equipped tanks. Now, in order for the weight to stay within reasonable bounds, the armour design has to be reasonable. An uniform armour thickness is simply stupit idea. It means that both of the two increased armour thickness and increased veicle size will result in a very, very rapit weight gain of the said veicle. Nobody ellse did use uniform armour thickness for a very, very good reason. The French would not have had this trouble if they had had a sensible design to begin with.194.144.20.188 (talk) 22:41, 18 January 2008 (UTC)

Well, a uniform armour, if thick enough, has the major advantage of giving all-round effective protection. So this design feature was not totally inane, as is suggested by the fact that the contemporary PzKpfw III Ausf. E also had a uniform armour thickness of 30 mm!--MWAK (talk) 08:47, 19 January 2008 (UTC)

All tanks had some armour everywhere, thus granting all around protection at the very least against small arms fire, maschine guns and shell splinters, but generally only the frontal armour was made strong enough to have any hope to cope with cannon shells. On the contrary 30mm was the strength of the frontal part of the hull armour of the Panzer III E. The minimum armour thickness was less than that, or as litle as 10mm at minimum [1].194.144.20.188 (talk) 00:22, 20 January 2008 (UTC)

Well, discounting top and bottom — which in the case of the S 35 were also thinner. But the sides and the back of the Ausf. E had 30 mm armour, just as the front.--MWAK (talk) 07:11, 20 January 2008 (UTC)

Right, the notion that heavy armor on the sides and rear was a poor design choice was not yet apparent in 1940. Several other tanks being designed or first fielded around this time - the T-34, KV and T-50 - also had uniform thicknesses or, if not uniform, quite heavy armor on the sides and rear in proportion to the frontal armor. Together with the S35 and Pzkw-III, we're essentially speaking of the most modern tank designs in the world at the time, and some of the few with shell-proof armor. It took a bit of combat for everyone to figure out that armor should be thinned at the sides and rear in order to concentrate it up front. So the S35 and Pzkw-III are not anomalies for 1940, they are the norm. Regards, DMorpheus (talk) 00:56, 21 January 2008 (UTC)

Reliability and turret weight

"The operational flaw was its poor mechanical reliability" - just curious, do we have a serious source on this? The post-Tunisia campaign report by Capitaine Gibrius stated "the SOMUA tank can still be considered amongst the best from a mechanical point of view, it has the same speed, endurance, reliability and simplicity as the best American tanks. But its inferiority lies in its insufficient armament, etc." (cited in Pascal Danjou's booklet).

Also I do not think the commander could "swivel the turret around by the weight of his body". Maybe this was possible on lighter vehicles but the APX1CE weights around 2200 kg.

PpPachy 13:49, 2 April 2006 (UTC)

Yes, these are very good points. When I wrote this section, I did it on the spur of the moment — seeing that someone had merely added a section title from an apparent desire to learn more about the subject — and purely from memory, which is, certainly at my age, an unreliable source of knowledge. To address the points specifically:

1. The problems the Cavalry experienced were of course mainly those with the 50 vehicles of the first batch, as testified by the CEMAV. Most of those were remedied to some extent. Still some structural suspension and drive problems remained as can seen by the analysis that led to the changes planned for the S 40. This I combined with the opinion of Colonel Baillou, who of course wished for something much more on the lines of a Christie tank. I certainly didn't want to suggest that the S 35 was more unreliable than most tanks of its day: obviously it was superior in this respect and certainly to the alternative, the AMC 35, and to its companion, the H 35. Comparison to the latter vehicle may well account for the favourable opinion many in the field had of the SOMUA. In action, despite the use of rail transport whenever possible, the main cause of loss seems to have been that for any armoured unit withdrawing: breakdown. And weren't the remaining S 35s in North Africa sent to the scrap-heap for lack of spare parts shortly after Captain Gibrius filed his report? ;o)
2. Yes, the weight of the turret crossed my mind too. However knowing that the APX-R certainly was optionally moved this way, I assumed that even the APX1CE could be moved in a similar fashion. Just a matter of applying 50% more force, so to say, made easier by the extra room in the fighting compartment. But I must admit I was unable to find any reference to leather straps as used in the smaller turret. This is simply because it wasn't possible to unlock the turret as a good friend of mine pointed out to me this afternoon. Still, the smaller turret allowed for a high rotation speed in the improved versions: 18° per second as compared to about 14° for the larger German turrets.

In general this entire article is far from perfect. I intended to first study the documentation properly, then write a long article for the Dutch Wikipedia and then condense this for the English one. In reality I hastily wrote the English one first and only now get into the details :o)--MWAK 17:22, 2 April 2006 (UTC)

Polish offer

In 1938/1939 Poland wanted to buy 100 S-35 tanks (see R-35 for details). Does anybody know why was this request denied? Mieciu K 09:37, 5 February 2007 (UTC)

I can't find references but it should remembered that total deliverance up to September 1939 was only 270 and that the French had the greatest possible difficulty in 1940 to find enough casting capacity to increase production. So the obvious answer seems to be: the French hadn't even got enough S 35s to satisfy their own requirements, so they had nothing to spare for the Polish army :o).--MWAK 10:00, 5 February 2007 (UTC)

That's the first and most obvious answer. I was wondering if the French had a policy of not selling their latest military equipment abroad, or maybe Poland wasn't trusted enough. After all closer miltary ties and security guaratees were given to Poland just prior to the outbreak of the war. Mieciu K 10:11, 5 February 2007 (UTC)

That's also a very reasonable answer the S-35 was a French tank produced in France so probably exporting it would be considered only after the needs of the French armed forces have been met. Mieciu K 10:21, 5 February 2007 (UTC)

Well, the S 35 wasn't all that advanced so there was little danger that any military secrets would become known to the enemy :o). However it's true that there was some suspicion towards Poland. It had concluded a treaty with Germany in 1934, had taken part in the partition of Czechoslovakia and was thought in the Spring of 1939 to be susceptible to the German offer of cooperation, however transparent that might seem with hindsight.--MWAK 12:14, 5 February 2007 (UTC)

S35. Medium or cruiser?

I can see where MWAK is coming from on this, but I would suggest the link to Cruiser tank is somewhat confusing to readers. There were many fast mediums, including the T-34 and the M-4, which essentially met the criteria of a "cavalry" tank, in a period where tank roles and nomenclature were fast evolving. The British "Cruiser" concept itself, eventually morphed into the excellent Comet tank, itself the precursor of the Centurion tank. I would suggest the link to medium tank is more appropriate here. I cannot find (albeit from a cursory search) the S35 being described as a cruiser tank. Thoughts anyone? Irondome (talk) 20:32, 23 March 2017 (UTC)

The problem is of course, that Cavalry tank is a redirect to Cruiser tank. The obvious solution would be to create a separate, not Anglo-centric, article. In the meantime, the cruiser tank concept is probably slightly closer to the French AMC than a general "medium tank". But perhaps it's best not to link at all...--MWAK (talk) 20:50, 23 March 2017 (UTC)

I agree MWAK. The lack of an article describing the nuances of tank type development is a major problem. If information is available, it is scattered around perhaps over a dozen articles. We do need such an article covering the concept of the cavalry tank. We could alternatively expand the medium tank article, which would maybe work better, as there is an evolutionary linkage to the Sherman, T-34 and PZR III. I see the S35 as a fast, well armoured cavalry/medium which was way ahead of it's time. Just not linking seems a good solution till we have something better to link to. Irondome (talk) 21:04, 23 March 2017 (UTC)

MWAK, I have linked Cavalry tank in infobox to the Tanks in France interwar section. This takes the reader directly to some very relevant and French-specific information, while avoiding the Anglo-centric Cruiser tank article. Irondome (talk) 21:42, 23 March 2017 (UTC)

This seems an excellent solution!--MWAK (talk) 22:04, 23 March 2017 (UTC)