Pit blockades

Joni Mänttäri tarjoutui kirjoittamaan  ja kääntämään blogejani Salpalinjasta in English.  Mikäs siinä, ainakin Salpalinja-oppaille on hyödyksi lukea erilaisia alan tekstejä, joissa sanastokin vaihtelee kirjoittajansa mukaan. Pyydän kommentoimaan, miltä Jonin kieli ”kuulostaa”. Hänen kääntämänsä alkuperäinen tekstini on tässä: http://salpalinjansalat.blogspot.fi/2010/09/kaivantoesteet.html

Terho Ahonen

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Rock blockades are the lock of salpa-lines anti-tank defence. Salpa-line has 225 kilometers of this very finnish and big laboured blockade. To support these blockades, or where rock blockades weren´t possible to build, pit blockades were made. Salpa-line has these different width and different depth pits about 130 kilometers.

A pit blockade is like a big ditch, which will prevent a tank from crossing over it.

Naturally, the effect of the pit blockade was enhanced by stationing anti-tank and infrantry weapons to shoot parallel to the pit blockade (flanking the enemy). In any case, pit blockades had to be able to be controlled from defenders own side.

It was clear that when an enemy tank sees the pit blockade, it would stop for a moment to think wether it will try to cross the pit or back up. In that brief moment, the defenders has a great opportunity to shoot at the side of the tank.

Experiences about low pit blockades from winter war weren´t good. So, in mid-peace finnish defence forces focused on rock blockades. During trench warfare new orders were given about pit blockades measures and in summer 1944 they were shovelled especially at Vaalimaa- line.

At first, pit blockades measures were defined at five meters wide and three meters deep. At these measures, one meter of the pit produced 7,5 cubic meters of gravel. When finnish defence forces realized, that the pit blockade weren´t enough for i.e. T-34 tank, they changed the measures to seven meters wide and 3,5 meters deep. These measures produced over 10 cubic meters of gravel per one meter.

At Vaalimaa-line, a german pit blockade was transformed to a quick pit blockade. In finnish version the pits measures were 3,5 meters wide, teo meters deep, and the bottom of the pit was half a meter wide. The edges of the pit were made as steep as possible, however the angle had to be at least 55 degrees. This quick pit blockade produced only 4 cubic meters of gravel per one meter.

Quick pit blockades were combined with infrantry firing posts and the blockade also functioned as a connecting trench. Anti-tank posts were stationed in front of this trench and behind the line, machine-gun and anti-tank cannon posts were stationed.

Pit blockades were mostly made with shovels. At Luumäkis end of Hamina-Taavetti-line, three excavators were in use, appointed by the city of Helsinki. One of them was steam powered.

The excavators bucked wasn´t always the best, and the bottom of the pit blockade became too flat and wide. To pervent enemy tanks from using these flat bottomed pits as cover, large rocks were put in the pit.

In addition with pit blockades, enemy tanks movement were made more difficult with slope cuts. In these cuts the vertical part of the wall had to be at least 1,5 meters high. To prevent these walls ofcollapsing they were supported with wooden poles. In some parts, the edges of steep hills were build with seperate rocks as an tank trap. In theory it would work like this: An enemy tank realizes the edge of the hill and brakes hard. That´s when the rocks under the tank collapses sending the tank to the bottom of the hill. After that the tank was easy to destroy or capture.

This text was translated from blog "Salpalinjan salat". Original text written by Terho Ahonen.

JONI MÄNTTÄRI