“It seemed like a good idea at the time”
Times of war can lead to unorthodox solutions to unforeseen problems. Sometimes these are successful; the Duplex Drive tank, the jet engine, night vision, and reactive armor. Sometimes these aren’t so successful…
The designs talked about here are not among the former. This article is a collection of little-known projects by Nazi Germany to mount naval artillery, super heavy siege cannons, and railway guns on the combined chassis of two or more tanks. These designs are quite obscure and do not have enough information to warrant their own individual articles.
Coming from 1943 is possibly one of the strangest ground fighting vehicles ever designed; the Project NM was a massive wooden warehouse structure atop a steel girder frame transported by three turretless Tiger Ausf.E tanks. The entire assembly measured about 17 meters wide by 15 meters long. Inside the wooden warehouse were three turrets mounted line abreast armed with 12.8 cm cannons. The center turret was slightly staggered behind the other two. The cannons pointed back over the rear of the vehicle, poking out through the doors of the warehouse. At the ‘front’ was a single Tiger tank while the other two Tigers were under the rear.
There are two schools of thought as to what the purpose of this vehicle was. The first is that it was destined for use on the plains of the Eastern Front, but there are several problems with this. Firstly, a large warehouse slowly creeping across a field isn’t very inconspicuous. Second, the NM would be unable to cross rivers, neither by fording, due to the rigidity of its construction, nor by bridges, due to its width. As a rigid structure, the NM would be unable to cope with all but the slightest changes in ground slope.
The second possible use for the vehicle is as a mobile coastal defense installation, for example as part of the Atlantikwall. This seems the more reasonable use, as a warehouse on the coastline isn’t likely to draw attention. Just who the project is attributed to is unknown as well, whether it was the Heer (Army) or the Kriegsmarine (Navy). Suspected use, armament, and the name all point to it being a Kriegsmarine project. The Kriegsmarine often designated their projects with capital letters, while the Heer did not. The armament, consisting of three 12.8 cm guns in separate turrets is another indication that the NM was a Kriegsmarine project. The Kriegsmarine referred to all their 128 mm guns as 127 mm guns, probably in order to avoid confusion with the Heer’s cannons. Assuming the NM was a Kriegsmarine project, its armament would have been either 12.7 cm SK C/34, or 12.7 cm SK C/41 cannons, though the former is the more likely choice, as they were more widely used.
Operationally, the NM would likely be deployed to a coast region where an attack was expected, or where the defense needed strengthening. The vehicle would be reversed into position and possibly camouflaged to best appear as a non-threatening structure. When an enemy vessel was within range the doors of the warehouse would be opened, giving the guns a reasonable firing arc. The NM would have time enough to fire a few salvos before the enemy vessels finally realized they were being engaged by a warehouse and not surface vessels or gun emplacements. When return fire started coming in, the NM could drive forward to move itself out of the line of fire.
Unsurprisingly, attaching three Tiger chassis together with steel girders and putting a warehouse on top wasn’t seen as a very practical idea. The NM Project did not advance any further.
Projekt NM Blueprint (Source: Der Panzerkampfwagen Tiger und Seine Abarten – Walter J. Spielberger, 1997)
Tiger H als Tragfahrzeug für schwerste Geschütze
In January 1941 (perhaps this was a typo for 1942, as the project is only mentioned again in December of 1942, nearly two years later), the Waffenamt (German Army Weapons Agency) put out a requirement for a system for transporting the 24 cm Kanone 4.
The K 4 was a project to upgrade the underwhelming 24 cm K 3. Only 14 K 3 guns were built; the reason being was that they were much more time-consuming to set up and operate than comparable guns such as the 21 cm Mörser 18, while their advantage in performance was not significant enough to warrant the hassle. Little information is available on the K 4, other than basic measurements. The barrel length was a ‘L/72’ meaning it was 72 calibers long. (72 x 24 cm gives a total barrel length of 17.28 m) and the gun was meant to fire 160 kilograms (353 lb.) shells up to 49 kilometers (30.4 miles).
Both the firms of Krupp and Rheinmetall-Borsig responded to the requirement. Krupp’s design was to use two unarmored Panzer VI Tiger chassis; while Rheinmetall’s design used the Karl-Gerät chassis. Further information on Rheinmetall’s design is unavailable; presumably, it was rejected early on due to the Karl Gerät chassis being too slow and unmaneuverable.
On the 17th of December, 1942, the OKH (German Army High Command) sent letter Wa J Rü (WuG 6) Villa2 Nr. 9846/42 to Henschel, the manufacturer of the Tiger chassis, requesting the necessary parts to build a prototype. Assembly of the vehicle was to take place at one of Krupp’s plants. The order was signed under the name “Tiger H als Tragfahrzeug für schwerste Geschütze”, or “Tiger H as a carrier for the heaviest guns”.
Krupp’s design aimed to have greater speed and mobility than the lackluster Karl Gerät. The unarmored Tiger chassis weighed 25 tons each. In order to prevent one tank moving while the other wasn’t, which would have damaged the machine, the drive units of each chassis were intended to be hydraulically linked to stay at the same speed. The projected top speed was 30 to 35 kph (18.6 to 21.7 mph). Hydraulic jacks were to be installed in place of the turret in the Tiger chassis; these would support large cylinders which in turn supported the gun platform. The gun platform could be lowered onto its base plate and the Tigers driven away with minimum difficulty. Four outriggers would be deployed to stabilize the gun. Whether or not the gun had any reasonable degree of traverse once in firing position is unknown.
The gun platform was lowered in the center, like a heavyweight railroad flatcar, but even so, the assembly was more than twice as tall as a normal Tiger tank when in transport configuration. Additionally, the ground pressure for each unarmored unit was significantly higher than a normal Tiger tank. However, being too heavy to cross bridges was not seen as a concern as only one load-bearing unit would be on the bridge at one time, due to the vehicle being so long. The distance between the centers of the Tiger chassis was to be 20 to 22 meters (65.5 to 72.1 feet), to give a sense of scale, a normal tractor-trailer truck trailer is 53 feet, or 16.1 meters long.
On the 23rd of December, 1942, Henschel stated that they would be unable to produce more Tiger chassis for a Lastenträger vehicle alongside of normal Tiger production, as they were already at full capacity.
A single prototype of the K 4 was being constructed at Krupp of Essen, but this was destroyed in a bombing raid in March 1943. With the destruction of the prototype, the K 4 project was canceled. If it had not been canceled already, this was surely the death of the Tiger H als Tragfahrzeug für schwerste Geschütze as well.
24 cm Kanone 4 mit Lastenträger Tiger I (Drawing Copyright Hilary Louis Doyle)
Gerät 566 Lastenträger 606/5 für K 5/3 (Tiger)
As the first design was canceled due to the discontinuation of the intended weapon, and not because it was ridiculous and impractical, Krupp decided to persevere with the tank-based railway gun idea using the 28 cm K 5 instead. The K 5 (sometimes incorrectly referred to as Leopold – this was the name of an individual railway gun rather than the name for this system) was the most successful railway gun of World War II; 25 pieces were built in total. The railway version of the gun weighed 218 metric tons; this number is probably not far off from the weight of the tank-based gun had it been built.
To transport the K 5 Krupp chose the Panzer VI Tiger II chassis. The general construction was similar to that of the first design, however, it seems the second design had even thinner support cylinders. Coupled with the immense weight of the K 5, it is even more unlikely the mechanism for raising the gun into transport position and lowering the gun into firing position would be functional and reliable.
Note: The book ‘Der Panzerkampfwagen Tiger und Seine Abarten’ (Spielberger, 1997) seems to suggest that the gun barrel, gun carriage, and base plate were all transported separately. However, the same book shows the illustration below, which implies that the whole assembly was transported as a single unit. Transporting the weapon in pieces would help overcome the problems of its great size and weight, but would make assembly upon arrival a nightmare. The book also states that a separate Tiger II-based vehicle would bring along “closing pieces” for the gun.
The Gerät 566 Lastenträger 606/5 für K 5/3 (Tiger) would have used a late-war development of the K 5 gun; the K 5 Glatt. The K 5 Glatt had a 31 cm smoothbore gun tube that was designed to fire 136 kilograms (300 lb.) subcaliber fin-stabilized rounds called Pfeilgeschoß up to a range of 120 to 150 kilometers (74.5 to 93.2 miles). This was great enough range to fire on London. However, due to the implementation of the V1 ‘Buzz Bomb’ and V2 missile, the K 5 Glatt fell by the wayside. Only two were built, both in railway configuration.
28 cm Kanone 5 mit Lastenträger Tiger II (Drawing Copyright Hilary Louis Doyle)
28 cm DKM 44 auf Panther Langholzprinzip
This design comes from a drawing dated from September 1943, wherein Rheinmetall-Borsig proposed that two Panzerkampfwagen Panther chassis be used to transport their 28 cm Düsenkanone Marine (DKM) 44 recoilless coastal defense gun, then under development in Sömmerda for the Kriegsmarine.
The 28 cm DKM 44 was the largest recoilless cannon being developed in Germany at the time. Rheinmetall-Borsig was the primary, possibly only, firm conducting work on recoilless guns in the later half of the War. They were under contract by the Luftwaffe, Heer (Army), and Kriegsmarine to develop different calibers of recoilless guns for various uses. The two projects Rheinmetall-Borsig was working on for the Kriegsmarine were the 8,8 cm DKM 43, a cannon for small vessels that would normally not mount larger weaponry than machine guns, and the 28 cm DKM 44, a coastal defense gun to defend against enemy landing forces.
The 28 cm DKM 44 would have weighed 28,000 kg (28 metric tons), it had 10 degree barrel rifling, and an electrical ignition system. It was designed by Herr Osthues, and the ballistician for the gun was Engineer Weber. A prototype of the DKM 44 was apparently completed before the end of the war by Hanomag in Hanover, and had even undergone tests. Photographs and blueprints should exist for this gun, but as yet they have not been found.
It is not known where the idea to transport the gun with two Panther chassis originated, whether from Rheinmetall-Borsig or suggested by the Kriegsmarine. More likely it was the former, as the Kriegsmarine, with the exception of their other project on this page, the NM, normally had no involvement with tanks.
The name of Rheinmetall’s design was the 28 cm Düsenkanone auf Panther Langholzprinzip, which translated to English means 28 cm Recoilless Cannon on Panther Long Wood Principle. “Langholzprinzip” is the German term for the practice used in logging whereby fallen trees are attached to a truck at one end and to an independent set of trailing axles at the other. By doing this the logs are allowed to support themselves between the axles and negate the need for a trailer. This same principle was employed on the 28 cm Düsenkanone auf Panther, with one tank taking the place of the truck, and the other taking the place of the trailer, leaving the payload slung between them.
The first Panther had a support that would attach to a collar half-way up the 28 cm DKM 44’s barrel, while the second Panther had a large, crane-like structure that would hold the gun’s breech from above. In order to fire, the gun would be lowered to the ground by large hydraulic rams inside the hulls of the tank chassis. The Panthers would then disconnect from the gun and move away. The cannon could then be used as a normal gun emplacement, able to rotate on its pedestal. Inside the gun’s superstructure was stored 10 two-piece rounds.
There is no surviving evidence if this design was accepted to be the main mode of transporting the DKM 44, however there are very few alternatives for moving such a big gun. Nevertheless the War did not progress in Germany’s favor; the DKM 44 never became operational, and its function as a coastal defense gun was no longer needed.
28 cm DKM 44 auf Panther Langholzprinzip Blueprint Source
Nazi Germany is remembered, among other things, for hideously impractical, ludicrous ‘wonder weapons.’ The idea of making railway guns mobile by sticking multiple tanks together is probably one of the weirdest. In the end even the Nazis had enough sense to see that these designs were hopelessly impractical.
However designs for vehicle-based super heavy siege guns did go on, with such things as the 58 ton Grille 17/21, the 182 ton R 2, and the 1500 ton Landkreuzer P.1500. None of these designs made any impact on the course of the war; only the Grille 17/21 was partially built while the others remained on paper. The only design of this type to become operational, the Karl Gerät, remains a lasting symbol of Hitler’s megalomania and the embracing of unconventional designs by the Third Reich’s war machine.
Les Armes secrètes du IIIe Reich: Hitler aurait-il pu gagner la guerre? – Laurent Tirone, 2014
Enzyklopädie Deutscher Waffen 1939-1945: Handwaffen, Artillerie, Beutewaffen, Sonderwaffen Gebundene Ausgabe – T.J. Gander and Peter Chamberlain, 2008
Der Panzerkampfwagen Tiger und Seine Abarten – Walter J. Spielberger, 1997
Panther Variants 1942-1945 – Osprey New Vanguard, 1997
Tank Encyclopedia’s own illustration of the 28 cm DKM 44 auf Panther Langholzprinzip by Jaroslaw Janas.