"HITLER'S SUPER SIEGE MORTAR"

60 cm Karl-Gerät "Ziu" firing in Warsaw, August 1944.

 

 

 "Karl-Gerät" (040/041) (German literally "Karl-device") was a World War II German self-propelled siege howitzer (Mörser) designed and built by Rheinmetall. It was the largest self-propelled weapon to see service. Seven guns were built, but only six saw combat between 1941 and 1945.

 

 

 

 

It was used to attack the Soviet fortresses of Brest-Litovsk and Sevastopol, bombarded Polish resistance fighters in Warsaw and participated in the Battle of the Bulge and the attacks against the Remagen Bridgehead. Only one exists today, the others were scrapped after the war.

Development

In March 1936 Rheinmetall made a proposal for a super-heavy howitzer to attack the Maginot Line. Their initial concept was for a weapon that would be transported by several tracked vehicles and assembled on site, but the lengthy preparation time drove them to change it to a self-propelled weapon in January 1937.

A dud shell fired during the Warsaw Uprising

Extensive driving trials took place in 1938 and 1939 using the first Neubaufahrzeug tank prototype and a scale model to investigate the extremely high ground pressure and steering of such an enormous vehicle.
Firing trials took place in June 1939. The full-scale driving trials were held at Unterlüss in May 1940. General Karl Becker of the Artillery was involved in the development, from whom the huge weapon gained its nickname.

In total, seven Karl-Geräte howitzers were manufactured. The first six had the nicknames "Adam", "Eva", "Thor", "Odin", "Loki", and "Ziu"; the seventh, the research and test weapon (Versuchs-Gerät), had no name. Delivery of the six production vehicles took place from November 1940 to August 1941.

60 cm Mörser Karl pictured during shelling of targets in and around Sevastopol.

Gerät 040 Karl-Mörser 600 mm calibre.

Gerät 040 Karl-Mörserm the 600 mm Ziu

 Report

A meeting was held on 29 September by the OKH General der Artillerie to discuss the overall status of the Karl-Gerät, its supporting equipment and ammunition:

1. Karl-Geräte

Gerät Nr. I: Set up for both 040 and 041. Currently equipped with 040 with Battery 428.

Gerät Nr. II: Only set up as 040. Currently being overhauled in Jüterbog. Motor installation will be completed in about 14 days.

Gerät Nr. III: About 14 days ago the gun tube blew apart while test firing. Only about 50% is reusable. Hitler has decided that this Gerät is to be restored to full operating condition. However, the schedule for restoring it isn't known.

Gerät Nr. IV: Set up for both 040 and 041. Currently equipped as 040 with Battery 428.

Gerät Nr. V: Set up for both 040 and 041. Equipped as a 040, it will be sent to Battery 638 in Budapest.

Gerät Nr. VI: Only set up as 040. Came back from employment in Warsaw. Repairs will be completed in about 20 days.

Gerät Nr. VII: Versuchs-Gerät 041 Currently with the Waffenamt for test firing and obtaining firing table data. It is not currently operational because important components (engine) are being overhauled and won't be operational before April 1945.

2. Guns

Six 54 centimetres (21 in) 041 guns have been ordered. Three have been completed and are stored in Jüterbog. A decision on the other three is requested because delivery will take at least 14 months.

3. 35 ton Crane Karl-Geräte can only be employed when each battery has a 35 ton crane. Two are in service, one is in Jüterbog without its trailer, which was destroyed by fire.

4. Culemeyer-Strassenroller Each battery needs one complete set of these heavy transport trailers. The two sets in service are set up for 040. Three 16-wheel trailers set up for 040 are available. Another 24-wheel trailer must be acquired to employ any additional Mörser Karl.

5. Munitionsschlepper 13 total, of which 6 are with Batteries 428 and 638, 2 with the Weapon Department (Waffenamt) for 040, 2 converted to 041 and 2 available.

6. Ammunition a. Munition 040: 264 shells are immediately available, of which 150 are planned to be allotted to Battery 638. Another 96 will be completed in the next few days. 241 round are in Unterluss to change their high explosive filler. About 10 completed daily. Part of the cartridges must be reworked. Powder testing will occur on 5 October so that the rest of the ammunition can be refilled.

b. Munition 041: 50 concrete-piercing shells have been delivered to Hillersleben to be shot for firing table data in early October. 25 shells will still be delivered by the end of September, another 25 by the end of October, from then on 50 per month are planned. 50 high-explosive shells (Sprenggranaten) are to be completed for firing table data in November. In early 1945 a total of 60 HE and concrete-piercing shells are to be produced monthly.

Three days later Battery 638 was ordered to transfer to Budapest and was loaded without any Karl-Gerät. Nr. V was rerouted to Budapest to equip the battery. Battery 428 followed on 10-11 October 1944. Both batteries were ordered back to Warsaw on 19 October, although they didn't arrive until 28 October. On 6 November Battery 638 transferred one Karl-Gerät 040 to 428 and returned to Jüterbog on 10 November to rearm with a Geräte 041. Battery 428 didn't remain near Warsaw much longer and departed for Jüterbog itself on 15 November.

Battery 428 exchanged its guns for Nr. II and VI (both with Geräte 040) and departed for the West on 14 December 1944 to participate in Operation Watch on the Rhine (Unternehmen Wacht am Rhein), which would be known by Americans as the Battle of the Bulge, but didn't reach the front until 29 December. Battery 628 followed on 20 December after equipping with Nr. IV, the first 54 cm Gerät 041 to be committed to battle.

LOADING THE 60cm SHELL

Ammunition

The original heavy 60 cm concrete-piercing shells (schwere Betongranate) made a crater up to 15 m (49 ft) wide and 5 m (16 ft) deep. More range was desired and the light concrete-piercing shell (leichte Betongranate) 040 was introduced in 1942. Firing trials for the 54 cm shells were not completed until the end of 1944 and they were not used in combat before then. The original 60 cm heavy shell had no designation other than the name. The Gerät number was added for the newer shells.

 600mm Shells for Geraet 040
schwere Betongranate

• Explosive: 280 kg (*1)
• Length: 2,511 mm
• Weight: 2.17 ton
• Muzzle Velocity: 220 m/sec (charge 4)

The schwere Betongranate shell has a hollow room at the bottom (see the right figure and Fig.1 A) to hold charge (Fig.1 B). The room is closed by the lid (Fig.1 C). When the shell is loaded into the gun barrel, a cartrige (Fig.1 D) is placed and the breech is then shut.

leichte Betongranate

• Explosive: 220 kg (*2)
• Length: 1,991 mm
• Weight: 1.70 ton
• Muzzle Velocity: 283 m/sec (charge 9)
• Maxmum Range: 6640 m 

The leichte Betongranate shell does not have a hollow room. Like other heavy artilleries, the shell, charge (Fig.1 B), and a cartrige (Fig.1 D) are loaded as shown in Fig.1 below.

28th of August 1944, a building in Warsaw is hit by 2-ton mortar shell from a Karl-Geräte.

 

 

 

 

 

 

 

Fate

Karl-Gerät at the Kubinka Tank Museum, Russia.

In 1945, Nr. II ("Eva") as well as Nr. V ("Loki") were captured by US forces in the period 21 March to 11 April 1945. Nr. VII, the test weapon, was captured by the US Army in Hillersleben and shipped to Aberdeen Proving Grounds but later scrapped. Nr. VI ("Ziu") was captured by the Red Army, probably when they overran Jüterbog on 20 April 1945. This is on display at Kubinka, although marked as Nr. I ("Adam"). Nr. IV ("Odin") was also captured by the Red Army. The fates of guns Nr. I ("Adam") and Nr. III ("Thor") are not known. It is probable both were captured by the Red Army as their last known location was in Jüterbog, less than a month earlier.