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15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B
Bundesarchiv Bild 101I-216-0406-37, Russland, getarnter Panzer I B mit I.G. 33.jpg
A sIG 33 (Sf) on a Pz.Kpfw. I chassis in Russia, 1942
Type self propelled artillery
Place of origin Nazi Germany
Service history
In service 1940 - 1943
Used by Nazi Germany
Wars World War II
Production history
Designed 1939-1940
Manufacturer Alkett
Produced February 1940
Number built 38
Weight 8.5 tonnes (8.4 long tons; 9.4 short tons)
Length 4.67 metres (15 ft 4 in)
Width 2.06 metres (6 ft 9 in)
Height 2.8 metres (9 ft 2 in)
Crew Four

Armor 13 mm - 5 mm
15 cm schweres Infanteriegeschütz 33
Engine 6-cylinder, water-cooled Maybach NL38TR
100 horsepower (75 kW)
Transmission 5 forward, 1 reverse gears
140 kilometres (87 mi)
Speed 40 kilometres per hour (25 mph)

The 15 cm sIG 33 (Sf) auf Panzerkampfwagen I Ausf B (sometimes referred to as the Sturmpanzer I Bison[1]) was a German self-propelled heavy infantry gun used during World War II.

Development and history

A sIG 33 auf Panzerkampfwagen I in Greece in 1941

The Invasion of Poland had shown that the towed sIG 33 guns assigned to the infantry gun companies of the motorized infantry regiments had difficulties keeping up with the tanks during combat. The easiest solution was to modify a spare tank chassis to carry it into battle. A sIG 33 was mounted on the chassis of the Panzer I Ausf. B, complete with carriage and wheels, in place of the turret and superstructure. Plates 13 millimetres (0.51 in) thick were used to form a tall, open-topped fighting compartment on the forward part of the hull. This protected little more than the gun and the gunner himself from small arms fire and shell fragments, the loaders were completely exposed. The rearmost section of armor was hinged to ease reloading.

There was no room to stow any ammunition so it had to be carried by a separate vehicle. When mounted, the sIG 33 had a total 25° of traverse and could elevate from -4° to +75°. It used a Rblf36 sight. The chassis was overloaded and breakdowns were frequent. The vehicle's extreme height and lack of on-board ammunition were severe tactical drawbacks.

Thirty-eight were produced in February 1940 by Alkett. Thirty-six of these were organized into independent schwere Infanteriegeschütz-Kompanie ("Self-propelled Heavy Infantry Gun Companies"); mot.S. Numbers 701-706 and these were assigned to the 1st, 2nd, 5th, 7th, 9th, and 10th Panzer Divisions in the Battle of France[2] as well as Operation Barbarossa, (the invasion of the Soviet Union).[3] The 705th and 706th were destroyed at this time, belonging to the 7th and 10th Panzer Divisions respectively. Of the remaining companies, only the 701st participated in the opening stages of the subsequent Case Blue in 1942, although it, and its parent 9th Panzer Division, were transferred to Army Group Center by the end of the summer of 1942.[4] The last reference to them is with the 704th Company of the 5th Panzer Division during the middle of 1943.[5]


  1. Achtung Panzer Article
  2. Trojca & Jaugitz, p. 5
  3. Niehorster, 1941
  4. Niehorster, 1942
  5. Chamberlain & Doyle, p. 24


  • Chamberlain, Peter, and Hilary L. Doyle. Thomas L. Jentz (Technical Editor). Encyclopedia of German Tanks of World War Two: A Complete Illustrated Directory of German Battle Tanks, Armoured Cars, Self-propelled Guns, and Semi-tracked Vehicles, 1933–1945. London: Arms and Armour Press, 1978 (revised edition 1993) ISBN 1-85409-214-6.
  • Niehorster, Leo. German World War II Organizational Series; Volume 3/I: Mechanized Army Divisions (22 June 1941) Hannover, Germany: Niehorster, 1990
  • Niehorster, Leo. German World War II Organizational Series; Volume 4/I: Mechanized Army Divisions (28 June 1942) Hannover, Germany: Niehorster, 1994
  • Trojca, Waldemar and Jaugitz, Markus. Sturmtiger and Sturmpanzer in Combat. Katowice, Poland: Model Hobby, 2008 ISBN 978-83-60041-29-1

External links

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