(*) Finnish original smoke shell introduced around 1940 - 1941. Used only in these smoke throwers.

(**) Finnish smoke shell m/43 P introduced year 1943. Could be used both in these smoke throwers and normal 81-mm mortars.

During World War 2 most armies opted to use their mortars in firing both high-explosive shells and smoke shells, but for some reason Finnish Army decided to acquire smoke throwers designed especially for this task. While these smoke throwers could fire only smoke shells in technical sense they were mortars. As usual before actual production several prototypes were manufactured. The resulting weapon was basically a cheaper and lighter version of existing 81-mm mortar. It had the usual structure based to Stokes mortars: Barrel, bipod and base plate. Instead of mortar directors used for aiming normal mortars they had simple elevation meter, which roughly showed the elevation setting. Smoke throwers were structurally too light to fire high explosive shells. Two versions of these 81-mm smoke throwers were manufactured in large numbers:

• 81 mm smoke thrower m/41
• 81 mm smoke thrower m/42

From these two smoke thrower models m/42 seems to have been more common. Heaviest part of the smoke thrower was barrel (23.5 kg), while bipod weight 4.5-kg and base plate only 6-kg. The base plate was only 1.5-cm thick. During Continuation War smoke throwers were issued to engineer troops, which used them when necessary. Typically they were used to provide cover to own troops during attack or to confuse the enemy. As can be seen the biggest handicap of smoke throwers was their rather limited range, which often required brining them very close to immediate frontline.

Two kind of ammunition existed for smoke throwers. The original smoke shell designed for them was far from aerodynamic and weight about 2-kg. It was cylindrical shell resembling large flare gun round. It seems to have been introduced around 1940 - 1941 and contained three basic parts: Container, sealing lid and fuse. Container, lid and bottom were all made from 1-mm tin plate. The material used for producing the smoke was zinc-chloride and provided effective smoke cover for 1.5 - 2 minutes. The fuse used in this shell was 15-second time fuse. Maximum range with just primary propellant charge (similar as used in 81-mm mortars) offered maximum range of 500 meters. The maximum propellant charge that could be used was primary propellant charge + one secondary propellant charge, this combination gave maximum shooting range of 700 meters. Typical range dispersion with this round was 50 meters.

Smoke shell m/43 P was much more sophisticated. The material used to produce smoke was still inside cylindrical container and the shell had an obtuse front, but end of the container had been shaped better and the projectile had six wing tail similar to one used in high explosive mortar shells. This offered considerably better ballistics and allowed firing this smoke shell also from 81-mm mortars (in which case it had maximum range of 950 meters). Weight of this smoke shell was about 3.5 kg and it was 37.5-cm long. The material used to produce was smoke was Berger mixture, which burned effectively about 2 minutes. Fuse used in this smoke shell was simple inertia shell, which was activated by the impact of shell landing. Maximum range when fired from smoke thrower was about 1,000 meters. These smoke shells were transported in wooden crates each containing four shells.

Year 1960 Finnish Armed Forces sold all their smoke throwers to Interarmco, which exported. Smoke throwers sold off at that time contained 166 smoke throwers m/41, 246 smoke throwers m/42 and ten mixed smoke thrower models of 81-mm. Presumably these ten mixed smoke throwers were the prototypes manufactured before starting actual production. From viewpoint of military history not leaving at least few samples for Finnish museums was considerable blunder, but unfortunately this mistake was not unique at that time. The reason for getting rid of smoke throwers was likely due to deciding use only normal mortars also for firing smoke shells from that on.

- 120-mm smoke thrower m/42: During Continuation War Tampella manufactured twenty of these 120-mm smoke throwers for Finnish Army. Also they had the typical Stokes-based structure: Barrel, bipod and base plate. However when compared to Finnish 120 Krh/40 they were structurally much lighter. Mortar barrel used in them was light weight and both bipod and base plate were models normally used in 81-mm mortars. No information about the ammunition used seems to exist. Also Sweden bought four of these smoke throwers from Tampella during Continuation War. Last six of these smoke throwers were sold to Interarms in year 1960.

SOURCES:

Jatkosodan historia book series, parts 4 and 6.

Talvisodan historia book series, part 4.

Suomen Sota book series, part 11 Sotatalous by Colonel E.O. Tirronen.

Miinanheittäjistä kranaatinheittimiin by Jyri Paulaharju in Suomen Sotilas - Nettisotilas website.

Vesa Toivonen: Tampellasta Patriaan

Puolustusvoimien huolto 1918 – 1986 by Huoltoupseeriyhdistys Ry.

Suomen kenttätykistön historia, parts 1 - 2 by Jyri Paloharju

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Tykistömuseon 78 tykkiä by Unto Partanen.

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Puolustusvoimien huolto 1918 – 1986 by Huoltoupseeriyhdistys Ry

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Jalkaväkitykit (1926) (kevyt miinanheittäjä 16 ja jalkaväkikanuunat 14 ja 15).

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Finnish military archives, archive folder T18419

Finnish military archives, archive folder T19051/29/4

Finnish military archives, archive folder T19058/14

Finnish military archives, archive folder T19462

Finnish military archives, archive folder T19051/32

Finnish military archives, archive folder T20207/F16 sal

Finnish military archives, archive folder T20314/4

Finnish military archives, archive folder T20314/5

Vesa Toivanen and Juha Tompuri, thank you for providing assistance - I am truly grateful.

Special thanks to Sotamuseo (Finnish Military Museum), Helsinki.

Special thanks to Tykistömuseo (Finnish Artillery Museum), Hämeenlinna.

Special thanks to Jalkaväkimuseo (Finnish Infantry Museum), Kouvola.