Historical Information for Sturmtiger

Sturmtiger is the common name of a World War II German assault gun built on the Panzer VI Tiger I chassis and armed with a large naval mortar, the 38 cm SturmMörser RW61 L/5.4. Its primary task was to provide heavy fire support for infantry units fighting in urban areas. Only 18 were built in total, from battle-damaged Tiger tanks. The vehicle is also known under the names Tiger-Mörser, Sturmmörser Tiger and Sturmpanzer VI.

The idea for a heavy infantry support vehicle capable of demolishing heavily defended buildings or fortified areas with a single shot came out of the experiences of the heavy urban fighting in the Battle of Stalingrad in 1942. At the time, the Wehrmacht had only the Sturminfanteriegeschütz 33 available for destroying buildings, a Sturmgeschütz III variant armed with a 150 mm heavy infantry gun. Twelve of them were lost in the fighting at Stalingrad.

Its successor, the Sturmpanzer IV Brummbär was in production from early 1943, but the Wehrmacht still saw a need for a similar, but heavier armoured and armed vehicle. Therefore a decision was made to create a new vehicle based on the Tiger tank and arm it with a 210 mm howitzer.

However, this weapon turned out not to be available at the time and was therefore replaced by a 380 mm mortar rocket launcher, which was adapted from a Kriegsmarine depth charge launcher.

In September 1943 plans were made for Krupp to fabricate new Tiger I armored hulls for the Sturmtiger. The Tiger I hulls were to be sent to Henschel for chassis assembly and then to Alkett where the superstructures would be mounted. The first prototype was ready and presented to Adolf Hitler in October 1943. Delivery of the first hulls would occur in December 1943, with the first three Sturmtigers completed by Alkett by 20 February 1944.

Due to delays, Hitler did not request production of the weapon until 19 April 1944; 12 superstructures and weapons for the Sturmtiger would be prepared and mounted on rebuilt Tiger I chassis. The first three production series Sturmtigers were completed by Alkett on rebuilt Tiger I chassis in August 1944. Plans to complete an additional seven 38 cm Sturmtigers from 15 to 21 September 1944 were presented to Hitler in a conference on 18/20 August 1944. Ten Sturmtigers were produced in September, along with an additional five in December 1944.

Hitler had laid great importance on the special employment of the Sturmtiger and believed it would be necessary to produce at least 300 rounds of ammunition per month.
 
The Sturmtiger was based on the late model Tiger I, keeping its hull and suspension. The front of the Tiger's superstructure was removed to make room for the new fighting compartment housing the rocket launcher/mortar. This was located directly at the front of the vehicle, giving it a boxy appearance.

Compared to the regular Tiger tank, the Sturmtiger was much shorter, only 6.28 m compared to the Tiger's 8.45 m, due largely to the fact that it hadn't the protruding main gun of the latter. It also was slightly lower than the Tiger, 2.85 m compared to 3.00 m.

Armour

Since the Sturmtiger was intended for use in urban areas in close range street fighting, it needed to be heavily armoured to survive. Its frontal armour therefore was 150 mm thick, as well as sloped, while its side plates were still some 80 mm thick as was the rear plate. This pushed the weight of the vehicle up from the 57 tonnes of the regular Tiger to some 65 tonnes.

Weapons

The main armament was the 380 mm Raketenwerfer 61 L/5.4, a breech loading rocket launcher/mortar, which fired short range rocket propelled projectiles. These projectiles were roughly 1.5 metre in length and could either contain a high explosive charge of 125 kg or a shaped charge for use against fortifications, which could penetrate up to 2.5 metres of reinforced concrete. The stated range of the former was 5,650 metres. The weight of the complete rounds was 345-351 kg. A normal charge first accelerated the projectile to 45 m/s, the 40 kg rocket charge then boosted this to about 250 m/s.

The design of the rocket launcher caused some problems, as the hot rocket exhaust could not be vented into the fighting compartment but neither could the barrel withstand the pressure if the gasses were not vented. Therefore a ring of ventilation shafts were put around the barrel which channelled the exhaust and gave the weapon somewhat of a pepperbox appearance.

Because of the bulkiness of the ammunition, only 14 rounds could be carried, of which one was already loaded, with another in the loading tray. The rest were carried in two storage racks. To help with the loading of ammunition into the vehicle, a loading crane was fitted at the rear of the superstructure, next to the loading hatch. Even then, the entire five man crew had to help with the loading.

It was intended that each Sturmtiger would be accompanied by an ammunition carrier built on the same tiger 1 chassis but only one carrier was completed

At the loading hatch's rear was located the 90 mm NbK 39 Naverteidegungswaffe ("Close defence weapon"), which was used for close range defence against both armoured vehicles and infantry. This could be used in a 360 degree circle around the vehicle and was basically a short range grenade launcher.

For defence against infantry attacks, there was a mount in the front for a 7.92 mm MG34 machine gun.

Combat

The original role of the Sturmtiger was intended to be as a heavy infantry support vehicle, to help with attacks on heavily fortified or built-up areas. By the time the first Sturmtigers were available however, the situation for Germany had changed for the worse, with the Wehrmacht being almost exclusively on the defensive rather than the offensive.
Three new Panzer companies were raised to operate the Sturmtiger: Panzer Sturmmörser Kompanien (PzStuMrKp) (Armored Assault Mortar Company) 1000, 1001 and 1002. These originally were supposed to be equipped with fourteen vehicles, but this figure was later reduced to four each, divided into two platoons.

PzStuMrKp 1000 was raised on 13 August 1944 and fought during the Warsaw Uprising with two vehicles, as did the prototype in a separate action, which may have been the only time the Sturmtiger was used in its intended role. PzStuMrKp 1001 and 1002 followed in September and October. Both PzStuMrKp 1000 and 1001 served during the Ardennes Offensive, with a total of seven Sturmtigers.

After this offensive, the Sturmtigers were used in the defence of Germany proper, mainly if not exclusively at the Western front. They proved to be excellent defensive weapons, hard to destroy except by air attack or heavy artillery bombardment. Few Sturmtigers were therefore destroyed by enemy action, with most being destroyed or abandoned by their crews after either a mechanical breakdown or because of fuel shortage

Technical Information