Multi-turrented Tanks in action

Like the Char, the T-35, and the Neubaufahrzeug. They generally had great firepower in the early war years but were extremely expensive and were just as easy to knock out.

Were the multi-turrets very effective in concentrating firepower?

 

No. Thats why the concept was discontinued. A dead end.

 

[SIZE=+1]Grosstraktor[/SIZE]
Having been subjected to attacks by enemy tanks and deprived of these valuable weapons by treaty, the German army in 1925 secretly initiated plans to design tanks. By April 1926, detailed specifications had been created for the design of a tank known as the 'Armeewagen 20', armed with a 75mm gun in a fully rotating turret. Following preliminary proposals, in March 1927 three firms were awarded contracts to design and built two chassis in soft steel. Grosstraktor I was built by Daimler-Benz, which had a 105mm gun for main armament, and the Grosstraktor II and III, built by Rheinmetall and Krupp, had a 75mm gun. A feature of all models was an auxiliary machine gun turret at the rear for enfilading enemy trenches as the vehicles crossed over.The name 'Grosstraktor' was first found in a document dated 14 March 1928. Assembly started in August 1928 at the Rheinmetall shop in Unterluess, and in late June 1929, six completed Grosstraktors were shipped to a secret testing facility near Kasan, Russia. Back in Germany after four years, further modifications and tests were conducted on the four serviceable Grosstraktor. The operational Grosstraktor were employed for troop training, and took part in the first Panzer-Division exercise in August 1935. Grosstraktor Daimler-BenzGrosstraktor Rheinmetall[SIZE=+1]NeubauFahrzeug[/SIZE]
Germany showed little interest in the heavy or breakthrough tank which was so popular with the French and Soviet armies. However, in 1934 two prototype versions were produced under the transparent cover title of 'mittlere Traktor' or 'Neubaufahrzeug' (new construction vehicle), generally shortened to Nb.Fz. The design was heavily influenced by the multi-turreted design of the British 'Independent' and Russian heavy tanks. Both Krupp and Rheinmetall were invited to submit design proposals. Based on the better performance of their Grosstraktor, Rheinmetall was selected to design a chassis and a turret, while Krupp was only awarded a contract for a turret design. Following further design decisions, Rheinmetall was awarded contracts for two chassis and one turret. Neubau Fahrzeug Nr.1 was completed in 1934 with a round turret, armed with a 37mm gun mounted above a 105mm gun. Krupp designed the turret for Neubau Fahrzeug Nr.2 with the 37mm gun mounted coaxially beside the 75mm gun in a rectangular turret. Neubaufahrzeug Nr.2Neubau-Panzerkampfwagen VIn the Spring of 1935, three additional trial tanks were ordered, this time in armor plate. Three turrets assembled by Krupp were mounted on three chassis assembled by Rheinmetall to create Neubau Fahrzeug Nr.3-5 in 1936.The Neubaufahrzeug was very similar in size and layout to the Grosstraktor but incorporated new features, such as auxiliary gun turrets fore and aft, mounting twin MG13 machine-guns. The crew numbered seven -commander, driver, two gunners, two machine-gunners and a radio-operator. The maximum thickness was 14.5mm, and maximum speed was about 15 mph. In 1939 the NbFz was redesignated within the German ordnance classification as a standard design. Fahrzeug Nr.2 with the 75mm gun became the PzKpfw V and Fahrzeug Nr.1 with the 105mm gun became the PzKpfw VI. After the swift demise of these vehicles in 1940, the PzKpfw V and VI designations were transferred to the later Panther and Tiger.Propaganda photo of NbFz heavy tanks in OsloNeubaufahrzeug in Oslo, April 1940Although it was decided not to proceed with quantity production of the Nb.Fz., the prototypes were retained on the active list, and achieved fame in 1940 as the visual symbol of German armored might. In April 1940 these Nb.Fz. were shipped to Norway in a platoon attached to Panzerabteilung 40, since none of the PzKpfw IVs could be spared for the operation. They were landed at Oslo docks and another at Putlos. Cleverly posed propaganda photographs of the few vehicles in existence were flashed around the world as 'heavy tanks of the German Army in Oslo', although in fact the photographs actually showed all the heavy tanks the Germans then possessed. Goebbels described these vehicles as the PzKpfw V, causing some concern in Allied intelligence circles. Two remaining vehicles took part in the invasion of Russia but were unfortunate enough to be engaged by a group of KV-1s and destroyed.

Multi-turreted tanks

 

AFAIK the main cause of loss for the multiturretted heavy tanks was getting cought on a train !!
At least this is what I believe happened to both the French Char 2C unit and a number of T-35 which amount to the total use of heavy multiturretted vehicles by line units. Paradoxically the prototypes like SMK, T-100 and Neubaufahrzeug had a more interesting combat record.
On a more serious note I strongly doubt the secondary gunners would be effective in a crowded and noisy environment lacking good visibility , the main gunners can usually cound count on the tank commander spotting for them, secondary gunners can't and are unlikely to have decent optics/vision.

I'm concentrating on the heavies I have very little info on combat operations things like the RAM, A9 cruiser or the twin MG turret early T-26 but looking at how those designs evolved tells the story.

BTW we had a discussion of Neubaufahrzeug on
http://www.ww2f.com/weapons-wwii/26416-top-10-worst-tanks-war.html
around post 24, you may want to look into that.

 

The Soviet venture into them showed that the armor was too speard out and thin so as not to be effective against AT guns and the coordination between the turrets very poor.

 

You left out the US M2 and Polish 7TPDW too. There were quite a few multi-turreted designs. None lasted long. The Char 2C is discussed in the WWI Tank thread

 

There are two excellent boooks available from Barbarossa books (U.K.) on the T28 and T35 Russian tanks, the T35 in particular is very relevant to this thread as it gives the disposition and final fate of most of the T35 in service when the Germans attacked. Most were out of action due to mechanical failures and therefore many were destroyed by crews. Really interesting vehicles the Germans are supposed to have coined a term for them -Kinder Shreck -Things to frighten children.

T28 continued in service and some eventually became part of armoured trains.

One notably was the final act of the T35 was in German hands in 1945 when the trophy T35 was used in the vicinity of Kummersdorf.

As to other tank mentioned the Ram tank turret was not that much of a problem being a slightly modified M3 Cupola, the crew man was mostly underneath the "turret"- still your ear is close to the breach of the Mg- which could be interesting.

The A9 turrets were just about serviceable but a bit restricted esp. in the Desert.
The Crusader turret could not be used except in demonstrations and was eliminated not used- whatever.

Can't think of any occasions when the U.S. used the multi turreted light tanks outside training.