The Story Behind

Krupp 42 cm M-Gerat howitzer ‘Big Bertha’

As some of you are aware I build 1/32 scale WW1 dioramas, mainly with an artillery theme. My most recent model is a Krupp 42cm (16.5in) howitzer, known as Big Bertha after Bertha Krupp, the owner of the company that built them. These devastating weapons were effective against fortifications and were initially deployed by the Germans to destroy the Belgian fortresses in 1914.

This is a large model and when I compared it to other artillery models I have made in the same scale I came to appreciate how big it actually is. I also made a German officer to try and get a true feel of the size of this howitzer- the shell is approximately the same height as the officer! To provide further comparison, I photographed the model alongside a British 18pdr model in the same scale as below:

Howitzer shown in firing position. The shell shown is the smaller 850kg

Howitzer shown in loading position The development of this howitzer started back in the late 19th century when fortifications started to be built using ferro-concrete which could withstand the heaviest shells of the day - 21cm. To break them the Germans started looking for a heavier shell and started development of a 31cm mortar with a range of 8200 metres & weighing in at 30 tonnes. Previous weapons also proved ineffective against new fortifications being developed by the French. After use in the Russo-Japanese war it was found that large howitzers were more effective then mortars for attacking fortresses. So the Germans developed a 30.5cm howitzer. After successful trials it was decided to develop a larger calibre howitzer and the 42cm version was born in 1911. This was a ‘foundation’ gun without wheels and needing a solid base. It had a greater range of 14000 meters with a shell of 1,160kg but weighed 150 tonnes. These could only be moved by rail and therefore need to be located near a rail line. The design for a more transportable model was started. The result was the gun in the photo weighing in at 45 tonnes. To get this reduction in weight components had to be made lighter and the fallout from this was loss of range, down to 9300 metres together with a lighter shell (800kg) although the 1,160kg shell could still be fired. The howitzer was split into five separate loads for transport with their own special designed carriages and pulled by large Podeus agricultural tractors. Included on the carriages was a gantry to facilitate assembling the howitzer.

Ted Dixon

On a general note, the majority of German/Austrian heavy artillery used a sliding block breech mechanism while most British and French heavy artillery used interrupted screw breech mechanisms. The provision of the required obturation (sealing of the breech on firing) was obtained by expansion of brass shell cases in German guns and by a expanding metal/rubber seal in the case of British/French guns. This required brass cartridge cases to be provided for the German guns using up limited metal resources, extra transport and the need to return the cases for refilling. The British/French used charges in silk bags which were easier to transport, didn’t have to be returned for filling and didn’t use any metal. As you will see on the model there is a brass cartridge case ready for loading on the shell lift.

Diagram of a German Breech Mechanism

Photo of a British 12in gun breech mechanism. The obturator is the domed projection at the rear of the screw