Floating armored vehicles BAD-2 Floating armored vehicle BAD-2A prototype developed and built in 1932 at the Izhora plant under the leadership of chief designer N.Ya. Obukhov based on the chassis of a three-axle Ford-Timken truck. This was the first

The first “Floating Fortresses” These were narrow and long ships with low sides, 30-40 meters long, and only 4-6 meters wide. The displacement of 1* trireme was only 80-100 tons. Bow warship lengthened, and at the water level or under the water a heavy, iron or

Chapter VI Floating airfields Battle across hundreds of kilometers Almost in the middle of the sea route from Japan to America Hawaiian Islands. They stretch in a giant chain from west to east. The length of the chain is more than 2500 kilometers. At its eastern end, on the island of Honolulu,

The first floating airfields Even before 1914, some navies began to conduct interesting experiments, mainly with cruisers. These experiments were carried out secretly, so the cruiser allocated for them went to areas of the sea or ocean that were rarely visited by ships and at the same time

What kinds of mines are there? We already know about a mine that is installed at an anchor; it is called “anchor”. There are mines that are hidden at the bottom of the sea, at shallow depths. These mines are called bottom mines. Finally, there are also “floating” mines; they are placed on a probable path

MINES AND COUNTERMINES After people invented gunpowder, the underground mine war became fierce. In 1552, Tsar Ivan the Terrible besieged the city of Kazan. Russian troops captured the Kazan-Ka River, cutting off the Tatars from water. From a defector, the Tsar learned that the Tatars were fetching water in the dungeon to

BOOBY TRAPS The Nazis love to set traps. There are pocket watches lying in the middle of the road. If you bend down and take them in your hands, it’s an explosion. An excellent bicycle has been forgotten against the wall. If you roll it away, there will be an explosion. A submachine gun and a box of canned food are thrown at the side of the road. Pick them up from the ground - again

FLOATING TANKS AND ARMORED VEHICLES EXPERIENCED FLOATING TANKS Back in the late 20s, experimental amphibious armored vehicles with a crew of two and a mixed wheeled-tracked drive were built in Japan. In 1934–1935, attempts were made to make light tanks amphibious.

EXPERIENCED FLOATING TANKS Back in the late 20s, experimental amphibious armored vehicles with a crew of two and a mixed wheeled-tracked drive were built in Japan. In 1934–1935, attempts were made to make the “2592” “A-i-go” light tanks amphibious by changing

FLOATING TANKS "TYPE 3" AND "TYPE 5" On the basis of the "Chi-he" in 1943, the amphibious tank "Type 3" ("Ka-chi") with a 47-mm cannon and two machine guns was developed. The shape of the pontoons and the casing above the commander's dome is the same as that of the Ka-mi. The engine exhaust pipes are raised to the roof of the hull. In total there were

As noted in the previous section, the main feature of the classification of modern sea mines is the way they maintain their revenge at sea after being laid. Based on this feature, all existing mines are divided into bottom, anchor and drifting (floating).

From the section on the history of the development of mine weapons, it is known that the first sea mines were bottom mines. But the shortcomings of the first bottom mines, revealed during combat use, forced them to abandon their use for a long time.

Bottom mines were further developed with the advent of NVs that react to FPC. The first serial non-contact bottom mines appeared in the USSR and Germany almost simultaneously in 1942.

As noted earlier, the main feature of all bottom mines is that they have negative buoyancy and, after being set, lie on the ground, maintaining their place throughout the entire period of combat service.

The specific use of bottom mines leaves an imprint on their design. Modern bottom mines against NK are deployed in areas with depths of up to 50 m, against submarines - up to 300 m. These limits are determined by the strength of the mine body, the response radius of the NV and the tactics of the NK and submarine. The main carriers of bottom mines are NK, submarines and aviation.

The design and principle of operation of modern bottom mines can be considered using the example of an abstract synthetic mine, which combines all possible options as much as possible. The combat kit of such a mine includes:

Explosive charge with ignition device:

NV equipment:

Safety and anti-mine devices;

Power supplies;

Elements of an electrical circuit.

The mine body is designed to accommodate all of the listed instruments and devices. Considering that modern bottom mines are installed at depths of up to 300 m, their bodies must be strong enough and withstand the corresponding pressure of the water column. Therefore, the bodies of bottom mines are made of structural steels or aluminum-magnesium alloys.

In the case of laying bottom mines from aviation (laying altitude from 200 to 10,000 m), either a parachute stabilization system or a rigid stabilization system (parachuteless) is additionally attached to the hull. The latter provides for the presence of stabilizers similar to the stabilizers of aircraft bombs.

In addition, the bodies of aircraft bottom mines have a ballistic tip, thanks to which, when splashed down, the mine turns sharply, losing inertia and lies horizontally on the ground.

Due to the fact that bottom mines are mines with a stationary warhead, their radius of destruction depends on the amount of explosives, therefore the ratio of the explosive mass to the mass of the entire mine is quite large and amounts to 0.6...0.75, and in concrete terms - 250...1000 kg . Explosives used in bottom mines have a TNT equivalent of 1.4...1.8.

NVs used in bottom mines are passive type NVs. This is due to the following reasons.

1. Among active type NVs, acoustic ones are most widespread, because they have a longer detection range and better target classification capabilities. But for normal operation of such an NV, precise orientation of the transceiver antenna is necessary. It is technically difficult to ensure this in bottom mines.

2. Bottom mines, as already indicated, refer to mines with a stationary warhead, i.e. the radius of destruction of the target ship depends on the mass of the explosive charge. Calculations have shown that the radius of destruction of modern bottom mines is 50.. 60 m. This condition imposes a limitation on the parameters of the NV response zone, i.e. it should not exceed the parameters of the affected area (otherwise the mine will explode without causing damage to the chain ship). At such short distances, almost all primary FPCs are quite easily detected, i.e. A passive type NV is quite sufficient.

From 1.2.2 it is known that the main disadvantage of passive type NVs is difficulty in isolating a useful signal from a background of interference environment. Therefore, multi-channel (combined) NVs are used in bottom mines. The presence in such an NV of sensing devices that respond to various FPCs simultaneously makes it possible to eliminate the disadvantages inherent in single-channel passive NVs and to increase their selectivity and noise immunity.

The operating principle of a multi-channel NV bottom mine is discussed in the diagram (Fig. 2.1).

Rice. 2.1. Structural diagram of an NV bottom mine

When dropping a mine into the water, the PP (temporary and hydrostatic) are turned on. After they have been worked out, the power sources are connected to the long-term clock mechanism through the relay unit. The DFM ensures that the mine is brought into a dangerous position within a predetermined time after setting (from 1 hour to 360 days). Having worked out its settings, the DFM connects power supplies To NV scheme. the mine goes into firing position.

Initially, the duty channel is turned on, consisting of acoustic and inductive sensing devices and a common (for both) analyzing device.

When a target ship enters the response zone of the duty channel, its magnetic and acoustic fields affect the DC receiving devices (IR induction coil and acoustic receiver - AP). In this case, EMFs are induced in the receiving devices, which are amplified by the corresponding amplifying devices (UIC and UAC) and analyzed by duration and amplitude by the duty channel analyzing device (AUD). If the value of these signals is sufficient and corresponds to the reference one, relay P1 is activated, connecting the combat channel for 20...30 s. The combat channel, accordingly, consists of a hydrodynamic receiver (GDR), an amplifier (UBK) and an analyzing device (AUUBK). its hydrodynamic field affects the sensing devices of the combat channel, a signal is sent to the ignition device and the mine is detonated.

In the event that no useful signal is received at the receiving device of the combat hydrodynamic channel, the analyzing device perceives the signals received from the duty channel as the influence of non-contact trawls and turns off the NV circuit for 20...30 b: after this time, the duty channel is turned on again.

The design and principle of operation of the remaining elements of the combat channel of this mine were discussed earlier.

German aircraft bottom mine LMB
(Luftmine B (LMB))

(Information on the mystery of the death of the battleship "Novorossiysk")

Preface.

On October 29, 1955, at 1 hour 30 minutes, an explosion occurred in the Sevastopol roadstead, as a result of which the flagship of the Black Sea Fleet, the battleship Novorossiysk (formerly Italian Giulio Cezare), received a hole in the bow. At 4:15 a.m., the battleship capsized and sank due to the unstoppable flow of water into the hull.

The government commission that investigated the causes of the death of the battleship named the most likely cause an explosion under the bow of the ship of a German sea-bottom non-contact mine of the LMB or RMH type, or simultaneously two mines of one or another brand.

For most researchers who have studied this problem, this version of the cause of the event raises serious doubts. They believe that an LMB or RMH type mine, which could possibly lie at the bottom of the bay (divers in 1951-53 discovered 5 LMB type mines and 19 RMH mines), did not have sufficient power, and its explosive device could not lead to mine to explosion.

However, opponents of the mine version mainly point out that by 1955 the batteries in the mines were completely discharged and therefore the explosive devices could not go off.
In general, this is absolutely true, but usually this thesis is not convincing enough for supporters of the mine version, since opponents do not consider the characteristics of mine devices. Some of the supporters of the mine version believe that for some reason the clock devices in the mines did not work as expected, and on the evening of October 28, being disturbed, they went off again, which led to the explosion. But they also do not prove their point of view by examining the design of the mines.

The author will try to describe as fully as possible today the design of the LMB mine, its characteristics and methods of activation. I hope that this article will bring at least a little clarity to the causes of this tragedy.

WARNING. The author is not an expert in the field of sea mines, and therefore the material below should be treated critically, although it is based on official sources. But what to do if experts in naval mine weapons are in no hurry to introduce people to German naval mines.
A dedicated land traveler had to take on this matter. If any of the maritime specialists deems it necessary and possible to correct me, then I will be sincerely glad to make corrections and clarifications to this article. One request is not to refer to secondary sources (works of fiction, memoirs of veterans, someone's stories, justifications of naval officers involved in the event). Only official literature (instructions, technical descriptions, manuals, memos, service manuals, photographs, diagrams).

German seaborne, aircraft-launched mines of the LM (Luftmine) series were the most common and most frequently used of all non-contact bottom mines. They were represented by five various types mines installed from aircraft.
These types were designated LMA, LMB, LMC, LMD, and LMF.
All these mines were non-contact mines, i.e. for their operation, direct contact of the ship with the target sensor of a given mine was not required.

The LMA and LMB mines were bottom mines, i.e. after being dropped they fell to the bottom.

The LMC, LMD and LMF mines were anchor mines, i.e. Only the mine’s anchor lay on the bottom, and the mine itself was located at a certain depth, like ordinary sea mines of contact action. However, the LMC, LMD and LMF mines were placed at a depth greater than the draft of any ship.

This is due to the fact that bottom mines must be installed at depths not exceeding 35 meters, so that the explosion could cause significant damage to the ship. Thus, the depth of their application was significantly limited.

Non-contact anchor mines could be installed at the same sea depths as conventional contact anchor mines, having the advantage over them that they can be placed not at a depth equal to or less than the drafts of ships, but much deeper and thereby complicate their trawling .

In the Sevastopol Bay, due to its shallow depths (within 16-18 meters to the silt layer), the use of LMC, LMD and LMF mines was impractical, and the LMA mine, as it turned out back in 1939, had an insufficient charge (half as much as in LMB) and its production was discontinued.

Therefore, to mine the bay the Germans used only LMB mines from this series. No other types of mines of this series were found either during the war or in the post-war period.

LMB mine.

The LMB mine was developed by Dr.Hell SVK in 1928-1934 and was adopted by the Luftwaffe in 1938.

There were four main models - LMB I, LMB II, LMB III and LMB IV.

The LMB I, LMB II, LMB III mines were practically indistinguishable from each other in appearance and were very similar to the LMA mine, differing from it in their greater length (298 cm versus 208 cm) and charge weight (690 kg versus 386 kg).

The LMB IV was a further development of the LMB III mine.
First of all, it was distinguished by the fact that the cylindrical part of the mine body, excluding the explosive device compartment, was made of waterproof plasticized pressed paper (press damask). The hemispherical nose of the mine was made of bakelite mastic. This was dictated partly by the characteristics of the experimental explosive device "Wellensonde" (AMT 2), and partly by a shortage of aluminum.

In addition, there was a variant of the LMB mine with the designation LMB/S, which differed from other options in that it did not have a parachute compartment, and this mine was installed from various watercraft (ships, barges). Otherwise, she was no different.

However, only mines with aluminum casings were found in Sevastopol Bay, i.e. LMB I, LMB II or LMB III, which differed from each other only in minor design features.

The following explosive devices could be installed in the LMB mine:
* magnetic M1 (aka E-Bik, SE-Bik);
* acoustic A1;
* acoustic A1st;
* magnetic-acoustic MA1;
* magnetic-acoustic MA1a;
* magnetic-acoustic MA2;
* acoustic with low-tone circuit AT2;
* magnetohydrodynamic DM1;
* acoustic-magnetic with low-tone circuit AMT 1.

The latter was experimental and there is no information about its installation in mines.

Modifications of the above explosive devices could also be installed:
*M 1r, M 1s - modifications of the M1 explosive device, equipped with devices against trawling by magnetic trawls
* magnetic M 4 (aka Fab Va);
* acoustic A 4,
* acoustic A 4st;
* magnetic-acoustic MA 1r, equipped with a device against trawling by magnetic trawls
* modification of MA 1r under the designation MA 1ar;
* magnetic-acoustic MA 3;

Main characteristics of the LMB mine:

Hexonite is a mixture of hexogen (50%) with nitroglycerin (50%). More powerful than TNT by 38-45%. Hence the mass of the charge in TNT equivalent is 939-1001 kg.

LMB mine design.

Externally, it is an aluminum cylinder with a rounded nose and an open tail.

Structurally, the mine consists of three compartments:

*main charge compartment, which houses the main charge, bomb fuse LHZusZ(34)B, clock for bringing the explosive device into firing position UES with hydrostatic self-destruction device LiS, hydrostatic mechanism for switching on the intermediate detonator and device for inactivating the bomb fuse ZUS-40..
On the outside, this compartment has a yoke for suspension to the aircraft, three hatches for filling the compartment with explosives and hatches for the UES, bomb fuse and mechanism for activating the intermediate detonator.

*explosive device compartment in which the explosive device is located, with a multiplicity device, a timer self-liquidator, a timer neutralizer, a non-neutralization device and a tamper-evident device.

*parachute compartment, which houses the stowed parachute. The terminal devices of some explosive devices (microphones, pressure sensors) go into this compartment.

UES (Uhrwerkseinschalter). The LMB mine used clock mechanisms for bringing the mine into firing position of the UES II or UES IIa types.

The UES II is a hydrostatic clock mechanism that begins timing only if the mine is at a depth of 5.18 m or more. It is turned on by the activation of the hydrostat, which releases the anchor mechanism of the watch. You should know that the UES II clock mechanism will continue to operate even if the mine is removed from the water at this time.
UES IIa is similar to UES II, but stops working if the mine is removed from the water.
The UES II is located under the hatch on the side surface of the mine on the opposite side to the suspension yoke at a distance of 121.02 cm from the nose. The diameter of the hatch is 15.24 cm, secured with a locking ring.

Both types of UES could be equipped with a hydrostatic LiS (Lihtsicherung) anti-recovery device, which short-circuited the battery to an electric detonator and exploded the mine if it was raised and it was at a depth of less than 5.18 m. In this case, the LiS could be connected directly to the UES circuit and was activated after the UES had completed its time, or through a forecontact (Vorkontakt), which activated the LiS 15-20 minutes after the start of the UES operation. LiS ensured that the mine could not be raised to the surface after it was dropped from the craft.

The UES clock mechanism can be preset to the required time to bring the mine into firing position, ranging from 30 minutes to 6 hours at 15-minute intervals. Those. the mine will be brought into firing position after being reset in 30 minutes, 45 minutes, 60 minutes, 75 minutes,......6 hours.
The second option for UES operation is that the clock mechanism can be pre-set for the time it takes to bring the mine into firing position within the range from 12 hours to 6 days at 6-hour intervals. Those. the mine will be brought into firing position after being reset in 12 hours, 18 hours, 24 hours,......6 days. Simply put, when a mine hits water to a depth of 5.18 m. or deeper, the UES will first work out its delay time and only then will the process of setting up the explosive device begin. Actually, the UES is a safety device that allows its ships to safely move near the mine for a certain time known to them. For example, during ongoing mining work in the water area.

Bomb fuze (Bombenzuender) LMZ us Z(34)B. Its main task is to detonate the mine if it does not reach a depth of 4.57.m. until 19 seconds have elapsed since touching the surface.
The fuse is located on the side surface of the mine at 90 degrees from the suspension yoke at 124.6 cm from the nose. Hatch diameter 7.62cm. secured with a retaining ring.
The fuse design has a clock-type timer mechanism that opens the inertial weight 7 seconds after the safety pin is removed from the fuse (the pin is connected by a thin wire to the aircraft's release device). After the mine touches the surface of the earth or water, the movement of the inertial weight triggers a timer mechanism, which after 19 seconds triggers the fuse and the explosion of the mine, if the hydrostat in the fuse does not stop the timer mechanism until this moment. And the hydrostat will only work if the mine by that moment reaches a depth of at least 4.57 meters.
In fact, this fuse is a mine self-destructor in case it falls on the ground or in shallow water and can be detected by the enemy.

Non-neutralization device (Ausbausperre) ZUS-40. The ZUS-40 non-neutralization device can be located under the fuse. It is intended to The enemy diver was unable to remove the LMZusZ(34)B fuse, and thereby make it possible to lift the mine to the surface.
This device consists of a spring-loaded striker, which is released if you try to remove the LMZ us Z(34)B fuse from the mine.

The device has a firing pin 1, which, under the influence of a spring 6, tends to move to the right and puncture the igniter primer 3. The movement of the firing pin is prevented by a stopper 4, resting on the bottom of a steel ball 5. The non-destructive device is placed in the side ignition cup of the mine under the fuse, the detonator of which fits into the socket of the non-destructive device . The striker is moved to the left, as a result of which the contact between it and the stopper is broken. When a mine hits water or soil, the ball flies out of its socket, and the stopper, under the action of spring 2, falls down, clearing the way for the striker, who is now restrained from puncturing the primer only by the fuse detonator. When the fuse is removed from the mine by more than 1.52 cm, the detonator leaves the liquidator socket and finally releases the striker, which pierces the detonator cap, the explosion of which explodes a special detonator, and from it the main charge of the mine explodes.

From the author. Actually, the ZUS-40 is a standard non-neutralization device used in German aerial bombs. They could be equipped with most high-explosive and fragmentation bombs. Moreover, the ZUS was installed under a fuse and a bomb equipped with it was no different from one that was not equipped with one. In the same way, this device could be present in the LMB mine or not. A few years ago, an LMB mine was discovered in Sevastopol, and when trying to dismantle it, two home-grown deminers were killed by the explosion of the mechanical guard of the explosive device (GE). But only a special kilogram charge worked there, which was designed specifically to shorten excessive curiosity. If they had begun to unscrew the bomb fuse, they would have saved their relatives from having to bury them. Explosion 700 kg. hexonite would simply turn them into dust.

I would like to draw the attention of all those who like to delve into the explosive remnants of war to the fact that yes, most German capacitor-type bomb fuses are no longer dangerous. But keep in mind that under any of them there may be a ZUS-40. And this thing is mechanical and can wait for its victim indefinitely.

Intermediate detonator switch. Placed on the opposite side of the bomb fuse at a distance of 111.7 cm. from the nose. It has a hatch with a diameter of 10.16 cm, secured with a locking ring. The head of its hydrostat protrudes onto the surface of the side of the mine next to the bomb fuse. The hydrostat is locked by a second safety pin, which is connected with a thin wire to the aircraft's release device. The main task of the intermediate detonator switch is to protect against a mine explosion in case of accidental activation of the explosive mechanism before the mine reaches depth. When the mine is on land, the hydrostat does not allow the intermediate detonator to connect to the electric detonator (and the latter is connected by wires to explosive device) and if the explosive device is accidentally triggered, only the electric detonator will explode. When the mine is dropped, simultaneously with the safety pin of the bomb fuse, the safety pin of the intermediate detonator switch is pulled out. Upon reaching a depth of 4.57 meters, the hydrostat will allow the intermediate detonator to connect with the electric detonator.

Thus, after separating the mine from the aircraft, the safety pins of the bomb fuse and the intermediate detonator switch, as well as the parachute pull pin, are removed using tension wires. The parachute cap is dropped, the parachute opens and the mine begins to descend. At this moment (7 seconds after separation from the aircraft), the bomb fuse timer opens its inertial weight.
At the moment the mine touches the surface of the earth or water, the inertial weight due to impact with the surface starts the bomb fuse timer.

If after 19 seconds the mine is not deeper than 4.57 meters, then the bomb fuse detonates the mine.

If the mine has reached a depth of 4.57 m before the expiration of 19 seconds, then the timer of the bomb fuse is stopped and the fuse does not take part in the operation of the mine in the future.

When the mine reaches a depth of 4.57m. The hydrostat of the intermediate detonator switch sends the intermediate detonator into connection with the electric detonator.

When the mine reaches a depth of 5.18 m. The UES hydrostat starts its clockwork and the countdown begins until the explosive device is brought into firing position.

In this case, after 15-20 minutes from the moment the UES clock starts operating, the LiS anti-recovery device may turn on, which will detonate the mine if it is raised to a depth of less than 5.18 m. But depending on the factory presets, LiS may not be turned on 15-20 minutes after starting the UES, but only after the UES has completed its time.

After a predetermined time, the UES will close the explosive circuit to the explosive device, which will begin the process of bringing itself into a firing position.

After the main explosive device has brought itself into a combat position, the mine is in a combat alert position, i.e. waiting for the target ship.

The impact of an enemy ship on the sensitive elements of the mine leads to its explosion.

If the mine is equipped with a timer neutralizer, then depending on the set time in the range from 45 to 200 days, it will separate the power source from the electrical circuit of the mine and the mine will become safe.

If the mine is equipped with a self-liquidator, then, depending on the set time within up to 6 days, it will short-circuit the battery to the electric detonator and the mine will explode.

The mine can be equipped with a device to protect the explosive device from opening. This is a mechanically actuated discharge fuse, which, if an attempt is made to open the explosive device compartment, will detonate a kilogram charge of explosives, which will destroy the explosive device, but will not lead to the explosion of the entire mine.

Let's look at explosive devices that could be installed in an LMB mine. All of them were installed in the explosive device compartment at the factory. Let us immediately note that it is possible to distinguish which device is installed in a given mine only by the markings on the body of the mine.

M1 Magnetic Explosive Device (aka E-Bik and SE-Bik). This is a magnetic non-contact explosive a device that responds to changes in the vertical component of the Earth's magnetic field. Depending on the factory settings, it can respond to changes in the north direction (magnetic lines of force go from the north pole to the south), to changes in the south direction, or to changes in both directions.

From Yu. Martynenko. Depending on where the ship was built, or more precisely, on how the slipway was oriented according to the cardinal points, the ship forever acquires a certain direction of its magnetic field. It may happen that one ship can safely pass over a mine many times, while another is blown up.

Developed by Hartmann & Braun SVK in 1923-25. M1 is powered by an EKT battery with an operating voltage of 15 volts. The sensitivity of the early series device was 20-30 mOe. Later it was increased to 10 mOe, and the latest series had a sensitivity of 5 mOe. Simply put, M1 detects a ship at distances from 5 to 35 meters. After the UES has worked for a specified time, it supplies power to M1, which begins the process of tuning to the magnetic field that is present in a given place at the time the A.L.A (a device built into M1 and designed to determine the characteristics of the magnetic field and accept them for zero value).
The M1 explosive device in its circuit had a vibration sensor (Pendelkontakt), which blocked the operation of the explosive circuit when the mine was exposed to disturbing influences of a non-magnetic nature (impacts, jolts, rolling, shock waves of underwater explosions, strong vibrations from working mechanisms and ship propellers working too closely). This ensured the mine's resistance to many minesweeping measures of the enemy, in particular to minesweeping using bombing, pulling anchors and cables along the bottom.
The M1 explosive device was equipped with a VK clock spring mechanism, which, when assembling the mine at the factory, could be set to work out time intervals from 5 to 38 seconds. It was intended to prevent the detonation of an explosive device if the magnetic influence of a ship passing over a mine stopped before a specified period of time. When the M1 mine's explosive device reacts to a target, it causes the clock solenoid to fire, thus starting the stopwatch. If the magnetic influence is present at the end of the specified time, the stopwatch will close the explosive network and detonate the mine. If the mine is not detonated after approximately 80 VK operations, it is switched off.
With the help of VK, the insensitivity of the mine to small high-speed ships (torpedo boats, etc.) and magnetic trawls installed on aircraft was achieved.
Also inside the explosive device was a multiplicity device (Zahl Kontakt (ZK)), which was included in the electrical circuit of the explosive device, which ensured that the mine exploded not under the first ship passing over the mine, but under a certain one.
The M1 explosive device used multiplicity devices of types ZK I, ZK II, ZK IIa and ZK IIf.
All of them are driven by a clock-type spring drive, the anchors of which are controlled by electromagnets. However, the mine must be brought into firing position before the electromagnet that controls the anchor can begin to operate. Those. the program for bringing the M1 explosive device into firing position must be completed. A mine explosion could occur under the ship only after the multiplicity device had counted the specified number of ship passes.
The ZK I was a six-step mechanical counter. I took into account triggering pulses lasting 40 seconds or more.
Simply put, it could be configured to pass from 0 to 6 ships. In this case, the change in the magnetic field should have lasted 40 seconds or more. This excluded the counting of high-speed targets such as torpedo boats or aircraft with magnetic trawls.
ZK II was a twelve-step mechanical counter. It took into account triggering pulses lasting 2 minutes or more.
ZK IIa was similar to ZK II, except that it took into account triggering pulses lasting not 2, but 4 minutes or more.
ZK IIf was similar to ZK II, except that the time interval was reduced from two minutes to five seconds.
The electrical circuit of the M1 explosive device had a so-called pendulum contact (essentially a vibration sensor), which blocked the operation of the device under any mechanical influences on the mine (moving, rolling, shocks, impacts, blast waves, etc.), which ensured the mine’s resistance to unauthorized influences. Simply put, it ensured that the explosive device was triggered only when the magnetic field was changed by a passing ship.

The M1 explosive device, being brought into firing position, was triggered by an increase or decrease in the vertical component of the magnetic field of a given duration, and the explosion could occur under the first, second,..., twelfth ship, depending on the ZK presets..

Like all other magnetic explosive devices, the M1 in the explosive device compartment was placed in a gimbal suspension, which ensured a strictly defined position of the magnetometer, regardless of the position in which the mine lay on the bottom.

Variants of the M1 explosive device, designated M1r and M1s, had additional circuits in their electrical circuit that provided increased resistance of the explosive device to magnetic mine trawls.

Production of all M1 variants was discontinued in 1940 due to unsatisfactory performance and increased battery power consumption.

Combined explosive device DM1. Represents an M1 magnetic explosive device
, to which a circuit with a hydrodynamic sensor is added that responds to a decrease in pressure. Developed by Hasag SVK in 1942, however, production and installation in mines began only in June 1944. For the first time, mines with DM1 began to be installed in the English Channel in June 1944. Since Sevastopol was liberated in May 1944, the use of DM1 in mines installed in Sevastopol Bay is excluded.

Triggers if within 15 to 40 sec. after M1 has registered the target ship (magnetic sensitivity: 5 mOe), the water pressure decreases by 15-25 mm. water column and remains for 8 seconds. Or vice versa, if the pressure sensor registers a decrease in pressure by 15-25 mm. water column for 8 seconds and at this time the magnetic circuit will register the appearance of the target ship.

The circuit contains a hydrostatic self-destruct device (LiS), which closes the explosive circuit of the mine if the latter is raised to a depth of less than 4.57 meters.

The pressure sensor with its body extended into the parachute compartment and was placed between the resonator tubes, which were used only in the AT2 explosive device, but in general were part of the wall of the explosive device compartment. The power source is the same for the magnetic and barometric circuits - an EKT type battery with an operating voltage of 15 volts.

M4 Magnetic Explosive Device (aka Fab Va). This is a non-contact magnetic explosive device that responds to changes in the vertical component of the Earth's magnetic field, both north and south. Developed by Eumig in Vienna in 1944. It was manufactured and installed in mines in very limited quantities.
Powered by a 9 volt battery. The sensitivity is very high 2.5 mOe. It is put into operation like the M1 through the UES armament watch. Automatically adjusts to the magnetic field level present at the mine release point at the time the UES ends operation.
In its circuit it has a circuit that can be considered a 15-step multiplicity device, which before installing the mine can be configured to pass from 1 to 15 ships.
No additional devices providing non-removal, non-neutralization, periodic interruption of work, or anti-mine properties were built into the M4.
Also, there were no devices that determined the duration of changes in magnetic influence. The M4 triggered immediately when a change in the magnetic field was detected.
At the same time, M4 had high resistance to shock waves of underwater explosions due to the perfect design of the magnetometer, which was insensitive to mechanical influences.
Reliably eliminated by magnetic trawls of all types.

Like all other magnetic explosive devices, the M4 is placed inside a compartment on a gimbal suspension, which ensures the correct position regardless of the position the mine occupies when it falls to the bottom. Correct, i.e. strictly vertical. This is dictated by the fact that magnetic power lines must enter the explosive device either from above (northern direction) or from below (south direction). In a different position, the explosive device will not even be able to adjust correctly, let alone react correctly.

From the author. Obviously, the existence of such an explosive device was dictated by the difficulties industrial production and a sharp weakening of the raw material base during the final period of the war. The Germans at this time needed to produce as many of the simplest and cheapest explosive devices as possible, even neglecting their anti-mine properties.

It is unlikely that LMB mines with an M4 explosive device could have been placed in the Sevastopol Bay. And if they were installed, then they were probably all destroyed by mine trawls during the war.

Acoustic explosive device A1 ship. The A1 explosive device began to be developed in May 1940 by Dr. Hell SVK and in mid-May 1940 the first sample was presented. It was put into service in September 1940.

The device responded to the noise of the ship's propellers increasing to a certain value with a frequency of 200 hertz, lasting more than 3-3.5 seconds.
It was equipped with a multiplicity device (Zahl Kontakt (ZK)) of type ZK II, ZK IIa, ZK IIf. More detailed information about ZK is available in the description of the explosive device M1.

In addition, the A1 explosive device was equipped with a tamper-evident device (Geheimhaltereinrichtung (GE) aka Oefnungsschutz)

The GE consisted of a plunger switch that kept its circuit open when the explosive compartment cover was closed. If you try to remove the cover, the spring plunger is released during the removal process and completes the circuit from the main battery of the explosive device to a special detonator, detonating a small 900-gram explosive charge, which destroys the explosive device, but does not detonate the main charge of the mine. The GE is brought into firing position before the mine is deployed by inserting a safety pin, which completes the GE circuit. This pin is inserted into the body of the mine through a hole located 135° from the top of the mine at 15.24 cm. from the side of the tail hatch. If the GE is installed in an enclosure, this hole will be present on the enclosure, although it will be filled and painted over so as not to be visible.

Explosive device A1 had three batteries. The first is a 9-volt microphone battery, a 15-volt blocking battery, and a 9-volt ignition battery.

The A1 electrical circuit ensured that it did not operate not only from short sounds (shorter than 3-3.5 seconds), but also from too strong sounds, for example, from shock wave depth charge explosions.

The variant of the explosive device under the designation A1st had a reduced sensitivity of the microphone, which ensured that it would not be triggered by the noise of acoustic mine trawls and the noise of the propellers of small ships.

The combat operation time of the A1 explosive device from the moment it is turned on ranges from 50 hours to 14 days, after which the microphone power battery fails due to the exhaustion of its capacity.

From the author. I would like to draw the readers' attention to the fact that the microphone battery and blocking battery are constantly in operation. There is no absolute silence underwater, especially in harbors and ports. The microphone transmits all the sounds it receives to the transformer in the form of alternating electric current, and the blocking battery, through its circuit, blocks all signals that do not meet the specified parameters. The operating current ranges from 10 to 500 milliamps.

Acoustic explosive device A4. This is an acoustic explosive device that responds to the noise of the propellers of a passing ship. It began to be developed in 1944 by Dr.Hell SVK and at the end of the year the first sample was presented. It was adopted for service and began to be installed in mines at the beginning of 1945.

Therefore, encounter A4 in LMB mines. installed in the Sevastopol Bay is impossible.

The device responded to the noise of the ship's propellers increasing to a certain value with a frequency of 200 hertz, lasting more than 4-8 seconds.

It was equipped with a multiplicity device of type ZK IIb, which could be installed for the passage of ships from 0 to 12. It was protected from the noise of underwater explosions due to the fact that the relays of the device were triggered with a delay, and the noise of the explosion was abrupt. It was protected from simulators of propeller noise installed in the bow of the ship due to the fact that the noise of the propellers had to increase evenly over 4-8 seconds, and the noise of the propellers emanating simultaneously from two points (the noise of real propellers and the noise of the simulator) gave an uneven increase .

The device had three batteries. The first is for powering the circuit with a voltage of 9 volts, the second is for powering the microphone with a voltage of 4.5 volts, and the third is a blocking circuit with a voltage of 1.5 volts. The microphone's quiescent current reached 30-50 milliamps.

From the author. Here too I would like to draw the attention of readers to the fact that the microphone battery and the blocking battery are constantly in operation. There is no absolute silence underwater, especially in harbors and ports. The microphone transmits all the sounds it receives to the transformer in the form of alternating electric current, and the blocking battery, through its circuit, blocks all signals that do not meet the specified parameters.

The A4st explosive device differed from the A4 only in its reduced sensitivity to noise. This ensured that the mine did not detonate against unimportant targets (small, low-noise vessels).

Acoustic explosive device with low-frequency circuit AT2. This is an acoustic explosive device that has two acoustic circuits. The first acoustic circuit reacts to the noise of the ship's propellers at a frequency of 200 hertz, similar to the A1 explosive device. However, the activation of this circuit led to the inclusion of a second acoustic circuit, which responded only to low-frequency sounds (about 25 hertz) coming directly from above. If the low-frequency circuit detected low-frequency noise for more than 2 seconds, then it closed the explosive circuit and an explosion occurred.

AT2 was developed in 1942 by Elac SVK and Eumig. Began use in LMB mines in 1943.

From the author. Official sources do not explain why the second low-frequency circuit was required. The author suggests that in this way a fairly large ship was identified, which, unlike small ones, sent quite strong low-frequency noises into the water from powerful heavy ship engines.

In order to capture low-frequency noise, the explosive device was equipped with resonator tubes that looked similar to the tail of aircraft bombs.
The photograph shows the tail section of an LMB mine with the resonator tubes of the AT1 explosive device extending into the parachute compartment. The parachute compartment cover has been removed to reveal the AT1 with its resonator tubes.

The device had four batteries. The first is for powering the primary circuit microphone with a voltage of 4.5 volts and the electric detonator, the second is with a voltage of 1.5 volts to control the low-frequency circuit transformer, the third is 13.5 volts for the filament circuit of three amplifying radio tubes, the fourth is 96 anode at 96 volts for powering the radio tubes.

It was not equipped with any additional devices such as multiplicity devices (ZK), anti-extraction devices (LiS), tamper-evident devices (GE) and others. Triggered under the first passing ship.

The American reference book on German naval mines OP1673A notes that mines with these explosive devices tended to detonate spontaneously if they found themselves in areas of bottom currents or during strong storms. Due to the constant operation of the normal noise contour microphone (underwater at these depths is quite noisy), the combat operation time of the AT2 explosive device was only 50 hours.

From the author. It is possible that it was precisely these circumstances that predetermined that of the very small number of samples of German naval mines from the Second World War, now stored in museums, the LMB / AT 2 mine is in many. True, it is worth remembering that the LMB mine itself could be equipped with a LiS anti-detachment device and a ZUS-40 anti-neutralization device under the bomb fuse LHZusZ(34)B. It could, but apparently quite a few mines were not equipped with these things.

If the microphone was exposed to the shock wave of an underwater explosion, which is characterized by a very rapid increase and short duration, a special relay responded to the instantly increasing current in the circuit, which blocked the explosive circuit for the duration of the passage of the blast wave.

Magnetic-acoustic explosive device MA1.
This explosive device was developed by Dr. Hell CVK in 1941, and entered service in the same year. The operation is magnetic-acoustic.

After dropping the mine, the process of working out the delay time with the UES clock and adjusting to the magnetic field that exists in a given place is completely similar to that in the M1 explosive device. Actually, MA1 is an M1 explosive device, with the addition of an acoustic circuit. The process of turning on and setting up is specified in the description of turning on and setting up the M1 explosive device.

When a ship is detected by a change in the magnetic field, the ZK IIe multiplicity device counts one pass. The acoustic system does not take part in the operation of the explosive device at this time. And only after the multiplicity device has counted 11 passes and registered the 12th ship, the acoustic system is connected to work.

Now, if within 30-60 seconds after the magnetic detection of the target the acoustic stage registers the noise of the propellers, lasting several seconds, its low-frequency filter will filter out frequencies greater than 200 hertz and the amplification lamp will turn on, which will supply current to the electric detonator. Explosion.
If the acoustic system does not register the noise of the screws, or it turns out to be too weak, then the bimetallic thermal contact will open the circuit and the explosive device will return to the standby position.

Instead of a ZK IIe multiplicity device, an interrupting clock (Pausernuhr (PU)) can be built into the explosive circuit. This is a 15-day electrically controlled on-off clock designed to operate the mine in a firing and safe position on 24-hour cycles. Settings are made in intervals that are multiples of 3 hours, for example, 3 hours on, 21 hours off, 6 hours on, 18 hours off, etc. If the mine does not go off within 15 days, then this clock is taken out of the circuit and the mine will go off during the first passage of the ship.

In addition to the hydrostatic LiS device built into the UES watch, this explosive device is equipped with its own hydrostatic LiS, which is powered by its own 9-volt battery. Thus, a mine equipped with this explosive device is capable of exploding when raised to a depth of less than 5.18 meters from one of the two LiS.

From the author. The amplification tube consumes significant current. Especially for this purpose, the explosive device contains a 160-volt anode battery. The second 15-volt battery powers both the magnetic circuit and the microphone, and the multiplicity device or interrupting clock PU (if installed instead of the ZK). It is unlikely that batteries that are constantly in use will retain their potential for 11 years.

A variant of the MA1 explosive device, called MA1r, included a copper outdoor cable about 50 meters long, in which an electric potential was induced under the influence of a magnetic linear trawl. This potential blocked the operation of the circuit. Thus, MA1r had increased resistance to the action of magnetic trawls.

A variant of the MA1 explosive device, called MA1a, had slightly different characteristics that ensured that the explosive chain was blocked if a decrease in noise level was detected, rather than a steady noise or an increase in it.

A variant of the MA1 explosive device, called MA1ar, combined the features of MA1r and MA1a.

Magnetic-acoustic explosive device MA2.

This explosive device was developed by Dr. Hell CVK in 1942, and entered service in the same year. The operation is magnetic-acoustic.

After dropping the mine, the process of working out the delay time with the UES clock and adjusting to the magnetic field that exists in a given place is completely similar to that in the M1 explosive device. Actually, the magnetic circuit of the MA2 explosive device is borrowed from the M1 explosive device.

When a ship is detected by a change in the magnetic field, the ZK IIe multiplicity device counts one pass. The acoustic system does not take part in the operation of the explosive device at this time. And only after the multiplicity device has counted 11 passes and registered the 12th ship, the acoustic system is connected to work. However, it can be configured for any number of passes from 1 to 12.
Unlike MA1, here, after the magnetic circuit is triggered at the moment the twelfth target ship approaches, the acoustic circuit is adjusted to the noise level available on at the moment, after which the acoustic circuit will issue a command to detonate a mine only if the noise level has risen to a certain level in 30 seconds. The explosive circuitry blocks the explosive circuit if the noise level exceeds a predetermined level and then begins to decrease. This ensured the mine's resistance to trawling by magnetic trawls towed behind a minesweeper.
Those. first, the magnetic circuit registers the change in the magnetic field and turns on the acoustic circuit. The latter registers not just noise, but increasing noise from quiet to threshold value and issues a command to explode. And if a mine is encountered not by a target ship, but by a minesweeper, then since the minesweeper is ahead of the magnetic trawl, at the moment the acoustic circuit is turned on, the noise of its propellers is excessive, and then begins to subside.

From the author. In this fairly simple way, without any computers, the magnetic-acoustic explosive device determined that the source of the magnetic field distortion and the source of the propeller noise did not coincide, i.e. It is not the target ship that is moving, but the minesweeper, pulling a magnetic trawl behind it. Naturally, the minesweepers involved in this work were themselves non-magnetic, so as not to be blown up by a mine. Embedding a propeller noise simulator into a magnetic trawl does not give anything here, because the noise of the minesweeper's propellers overlaps with the noise of the simulator and the normal sound picture is distorted.

The MA2 explosive device in its circuit had a vibration sensor (Pendelkontakt), which blocked the operation of the explosive circuit when the mine was exposed to disturbing influences of a non-magnetic nature (impacts, jolts, rolling, shock waves of underwater explosions, strong vibrations from working mechanisms and ship propellers working too closely). This ensured the mine's resistance to many minesweeping measures of the enemy, in particular to minesweeping using bombing, pulling anchors and cables along the bottom.
The device had two batteries. One of them, with a voltage of 15 volts, fed the magnetic circuit, and the entire electrical explosion circuit. The second 96-volt anode battery powered three amplifying radio tubes of the acoustic circuit

In addition to the hydrostatic LiS device built into the UES watch, this explosive device is equipped with its own hydrostatic LiS, which is powered by the main 15-volt battery. Thus, a mine equipped with this explosive device is capable of exploding when raised to a depth of less than 5.18 meters from one of the two LiS.

The MA 3 explosive device differed from the MA 2 only in that its acoustic circuit was set not for 20, but for 15 seconds.

Acoustic-magnetic explosive device with low-tone circuit AMT 1. It was supposed to be installed in LMB IV mines, but by the time the war ended this explosive device was in the experimental stage. Application of this explosion)